Executive Summary

This report addresses key issues that will be confronted in any negotiation to end the war in Ukraine. It provides an overview of the scholarly literature on territorial settlements following conflict. While interstate war for imperial conquest has been rare in the post-World War II world, there are relevant lessons to be learned from a broader range of territorial conflicts, including civil wars, separatist movements, and historical border disputes.

The study begins by delineating the main types and outcomes of territorial conflict, as well as key explanations for war termination. It then turns to analysis of negotiated settlements and mediation before addressing the key issues of what makes settlements successful or unsuccessful, as measured by durability and levels of cross-border violence.

Settlements are more likely to succeed under certain conditions:

  • Balance of power. Balance of power strengthens deterrence. Where power asymmetries are large, peace is dependent on the good will of the stronger party, which is suspect in post-conflict situations. In such situations, alliance with external states may be a necessity for the weaker state to deter aggression from the stronger one.
  • Partition and ethnic separation. Separating warring groups reduces contact and increases the ability to detect and defend against attacks. While “good fences” can make good neighbors in some instances, partition is often preceded by violent expulsions or killing of people based on their ethnicity or religion (ethnic cleansing). Ethnic cleansing violates norms of human rights and increases inter-communal resentment that can increase the chances of future conflict. Refugees, who have the “right to return” under international law, remain an important constituency in post-conflict relations and governance, particularly when housed in refugee camps for extended periods of time.
  • Strategic geography. When new borders are drawn or old borders reinstated, it is important that they be defensible by both sides—for example, by using natural geographical features like mountains or rivers.
  • Buffers. Buffer states or territories can reduce renewed hostility by separating forces, and thus reducing the possibility of surprise attacks or miscalculation. Buffer zones work best when they are mutually agreed, demilitarized, contain mechanisms for communication and crisis management, and are supported by credible deterrence on both sides. The Korean DMZ illustrates the most durable example of a successful buffer zone between two hostile powers.
  • Peacekeeping. Peacekeeping forces, particularly ones with military capabilities, have been consistently shown to improve the durability of negotiated settlements and ceasefires. Like buffer zones, peacekeepers can help to maintain distance between hostile parties. They also improve monitoring, communication, and crisis management.
  • External incentives or guarantees. In order to achieve and maintain negotiated settlements, incentives or guarantees offered by external states or international organizations can be important. External incentives such as economic aid or inclusion in regional organizations can shift zero-sum or negative-sum situations into positive-sum bargaining opportunities. Continued incentives can persuade disaffected states and actors to comply with the agreement.
  • Withdrawal of support by external patrons. Most long-term secessionist conflicts are maintained through the support of external patrons, typically co-ethnic or co-religionist neighbors or great powers. Durable territorial settlements require the withdrawal of support for separatism, often as one component of a comprehensive power-sharing agreement.

Finally, the study addresses the importance of post-conflict governance and reconstruction. Economic or political weakness is likely to undermine a post-conflict state’s ability to defend itself from future attacks. Good governance can reduce that possibility by increasing material resources, ability to mobilize the population, and willingness of external actors to support the state economically, politically, and militarily. In the wake of major conflicts, multilateral organizations such as the United Nations (UN) and the Organization for Security and Cooperation in Europe (OSCE) as well as national and multilateral aid agencies have played central roles in supporting the development of good governance, including curbing corruption, improving efficiency of service provision, equitable treatment for ethnic or political minorities, and human rights.

The success of post-conflict governance and reconstruction is affected by a variety of factors, some of which include:

  • Foreign role. Foreign support for post-conflict states can provide important financial resources, legal and technical expertise, maintain peace, mediate political bargains among political and social groups. The most successful examples of post-conflict governance and reconstruction have benefited from the involvement of multiple foreign actors, including the UN, OSCE, U.S., and EU.
  • Remittances and investment. While external financial aid can be important to post-conflict societies, it is generally dwarfed by remittances and foreign direct investment. For long-term economic development, FDI (much of which is typically provided by diaspora communities) is particularly important, so it is important to have a welcoming investment regime.
  • Political settlements. Compromises among the main political, social, ethnic, or religious parties are essential to the stability and functioning of post-conflict states. Because formerly warring parties are often able to return to armed conflict, power-sharing agreements must be supportive of minority rights. Foreign interlocutors and aid providers can have a key role in mediating lasting agreements.
  • External recognition. Higher levels of external recognition contribute to more capable post-conflict states. In addition to increasing the range of supporters and amounts of aid and expertise, external recognition increases confidence among potential investors. Unrecognized quasi-states, in contrast, suffer from low investment and circumscribed trading opportunities. 
  • Corruption. Corruption is an endemic problem in post-conflict societies, which can lead to low capacity, weak economic performance, and reemergence of conflict. Rule of law and anti-corruption can often be made more effective with external support, especially from organizations with extensive experience in reconstruction, such as the UN, OSCE, and EU.


This report seeks to contribute to debate on key issues that will be confronted in any negotiation to end the war in Ukraine. It surveys the English-language academic and policy literatures regarding territorial wars, focusing in particular on how wars end and how to prevent future recurrence of conflict. Territorial conflicts are highly specific to their time and place, but it is also possible to identify common themes and issues. Although the literature does not provide a one-size-fits-all roadmap for building durable and equitable peace, theory and history can guide leaders and negotiators in identifying opportunities, threats, and potential solutions.

Territorial wars are militarized interstate conflicts in which an aggressor seeks to change existing borders permanently and to directly control and/or alter the composition of the population living within the new borders. Resolving territorial wars raises particular challenges for both the belligerents and the international community, making durable post-conflict stability elusive. Despite the ever-present threat of violent conflict in the international system, interstate war across internationally recognized borders for the purposes of territorial aggrandizement has been very rare in the post-World War Two period, in sharp contrast to earlier periods. Scholarship has ascribed this shift to the declining benefits relative to costs of direct control of territory and populations, as well as the strengthening of international norms of sovereignty and the commitment of leading powers to defend the principle of territorial integrity and “border fixity.” Violent conflict in the international system is not particularly rare, but in the post-WWII period, it has consisted primarily of civil wars and insurgencies, transnational violence, foreign interventions in domestic conflicts, and border disputes. Wars of conquest—i.e., attempts to take over another recognized sovereign territory in full, such as those in divided Korea, Vietnam, and Yemen; the various Arab invasions of Israel between 1948 and 1973; the 1975-76 Indonesian takeover of East Timor (now Timor-Leste); and the 1991 Iraqi invasion of Kuwait—number in the single digits. Successful takeovers are even rarer: of the above-noted cases, only Vietnam exists today as a unified state that was created by conquest. Such takeovers are even rarer among major powers: the most authoritative database on international conflict states that, “The Russian invasion of Ukraine is the first large-scale interstate war in 20 years, and the first interstate armed conflict since World War II where a major power in the international system seeks both territorial gains for itself and the subjugation of another state through regime change.” There is, therefore, no well-established academic literature on post-WWII interstate territorial settlements. In this paper, we draw on a broader range of conflicts, ranging from civil wars to border skirmishes to interstate wars, to draw lessons about the challenges of and options for post-conflict territorial and population reorganization and stabilization. 

The paper is organized as follows. First, we describe categories of interstate conflict—i.e., military conflict between two or more established states. Next, we describe the options available to policy makers for post-conflict resolution. Then we turn to the academic literature on war termination, addressing key explanations including bargaining models, domestic politics, loss aversion, and the role of international mediation. We then discuss factors that affect the durability of post-conflict territorial settlements, including balance of power, partition, geography, and peacekeeping operations. Finally, we turn to the governance and stability of newly-created states and quasi-states resulting from conflict, including issues related to minority rights, language policy, and state capacity.


The post-WWII international system has been characterized by widespread violence, ranging from decolonization to civil wars to border skirmishes to proxy wars and even to full-scale invasions for purposes ranging from protecting civilians to overthrowing unfriendly governments to taking sides in civil wars.

In contrast with the rarity of wars of conquest like Indonesia’s two-decade incorporation of East Timor and Iraq’s attempted takeover of Kuwait, interstate wars for de facto territorial control or to overthrow unfriendly governments (or support friendly ones) have been more common. In some cases, including the Soviet invasion of Hungary, Czechoslovakia, and Afghanistan, the U.S. invasions of Afghanistan and Iraq, and the Vietnamese invasion of Cambodia, wars to overthrow unfriendly governments have led to extended occupations, but without attempting to assert sovereignty or substantially change borders. Interventions at the invitation of friendly governments constitute another category of interstate warfare, which in some cases have also led to extended troop presence inside those countries. Examples include the Soviet role in suppressing Poland’s Solidarity movement, U.S. participation in the Vietnam War, Cuban support of Marxist governments in Angola and Mozambique, and French interventions in various African countries. Another form of interstate war is foreign participation in civil wars, either as parties to the conflict or in hot pursuit of cross-border insurgency. Finally, conflicts over unsettled borders, whether due to colonial legacies, remoteness, sparse populations, or other factors have been common but are typically geographically limited. However, some border disputes do involve large, relatively densely populated territories, including Jammu and Kashmir (India-Pakistan), Sabah (Malaysia-Philippines), and Nagorno-Karabakh (Armenia-Azerbaijan). Many of these cases also reflect broader ethnic or religious conflicts.

The most common wars since World War II have been wars of division: civil wars and post-colonial independence wars. The post-WWII era has seen the establishment of a multitude of new states due to decolonization and domestic conflicts. Not all such state creations have been violent,8 but many have been. Moreover, even non-violent state creation (such as the negotiated end to colonial rule in British India) can lead to subsequent violence, whether in the form of civil strife, transnational violence such as terrorism or insurgent safe havens, or continued interstate conflict along borders. Not all unsettled territorial disputes lead to interstate violence; however, even initially uncontested territorial resolutions can lead to future conflicts, as the profusion of post-colonial cases clearly demonstrates.


While the scholarly literatures on these various types of territorial conflicts are surprisingly fragmented, there are important commonalities and lessons to be drawn among them in terms of the dynamics of conflict, termination or resolution, and post-resolution stability.

Territorial wars result in four ideal-types, several of which can become the basis for long-term stability between belligerents:

  • Absorption/conquest: This is the least common result in the post-WWII world, and is often temporary. Moreover, in many cases, the victorious power is only able to maintain control through repression. Examples of absorption enforced through repression include Israel’s incorporation of the West Bank/Gaza and Indonesia’s quarter century-long incorporation of East Timor. Repression is less necessary in cases where a local population prefers to be ruled by a neighboring state due to ethnic, linguistic, or religious ties.
  • New state creation: A variety of new states have been created through decolonization and breakups of multiethnic states. The breakup of multiethnic states through armed conflict has led in recent years to the establishment of Eritrea, various former Yugoslav states, Timor-Leste, and South Sudan, among others.
  • Buffer zone: A buffer zone is a “territory—a weak state or borderland—located between two significantly stronger rival states that share land borders with the buffer zone.” Buffer zones separate combatants physically, reducing both their capacity for military action (due to logistics, supply lines, etc.) and the likelihood of accidental confrontations that might lead to full-scale conflict. Buffer zones can be negotiated, unilateral, or de facto.
    • Successful negotiated buffer zones (“zones of management”) include the Korean Demilitarized Zone, which has prevented large-scale conflict between two heavily-armed states since 1953, and the demilitarization of the Sinai Peninsula in 1979, which enabled the Camp David Agreement between Egypt and Israel. States (typically ones that self-identify as neutral or non-aligned) can also fulfill this role. Austria and Finland have been identified as negotiated buffer states during the Cold War, despite being highly capable independent international actors.
    • Unilateral buffer zones are also common. Israel’s occupation of the West Bank and Sinai Peninsula provided an effective buffer against attacks for decades. Historically, the Warsaw Pact provided a buffer zone for the Soviet Union as forward defense against NATO.
    • De facto buffer zones include ungoverned borderlands. These can be geographically remote, sparsely populated territories like Arunachal Pradesh in India or the Amazonian and Patagonian hinterlands in South America. They can also be populated regions where direct governance is difficult due to landscape or ethnic conflicts (e.g., portions of the borders between Afghanistan and Pakistan, Thailand and Myanmar, and Kurdish areas along the borders of Iraq, Syria, and Turkey).
  • Frozen conflict: Frozen conflicts are unresolved conflicts where low-level violence continues, even though the main combatants have chosen not to commit to large-scale conflict due to both sides’ inability to achieve decisive victory.11 (In many cases, the actual combatants in frozen conflicts are subnational actors, such as ethnic separatists.) Patterns of territorial control may shift, but only incrementally. Frozen conflicts can last indefinitely, but can also flare up into active conflict due either to changing facts on the ground or changing calculations on the part of combatants. Prominent interstate examples include Jammu and Kashmir, South Ossetia, and Transnistria.


To better understand the challenges of post-conflict territorial settlements, it is important to consider the ways in which wars end. There is a considerable literature on war termination, which provides insight into the choices of leaders to pursue conflict or peace. Here, we focus on how and when belligerents agree not only to stop fighting (i.e., temporary ceasefire) but also on terms that are meant to prevent the recurrence of conflict. Ideally, war termination will lead to a durable settlement, but it is objectively the case that conflicts often do recur. We address the question of durability of post-conflict settlements in the next section. While peace is the ultimate goal of war termination and post-conflict settlement, war termination is an essential prerequisite to both.


Rationalist Approaches

Although the history of interstate conflict suggests that emotion, belief, and xenophobia play a big part in the initiation and continuation of warfare, much of the literature presupposes some degree of rational decision making on the part of leaders. In the early literature on war termination,13 scholars argued that war ends when the “loser” recognizes its position and accedes to the “winner’s” demands. The argument that war ends when the loser surrenders (e.g., war weariness) presupposed that the war aims of the belligerents (i.e., victory or defeat) remain fixed during the war. In the related literature on the duration of civil wars, scholars similarly assumed that civil wars end when one side quits. However, this raises the question of why a winning belligerent would not choose to increase its demands. Indeed, one study argues that “territorial change in war, especially acquisition of large and densely populated territories that have potential utility for greater power shifts, makes ceasefires more prone to failure” for this very reason.

Most current rationalist scholarship on war termination sees it as a kind of bargaining process, characterized by cost-benefit calculations by rational, unified actors. In other words, wars end when the combatants agree to a settlement that both prefer over continued fighting. Because combat provides new information about belligerents’ strengths and weaknesses, belligerents’ war aims may change during war. For example, even if a belligerent’s war aim was a territorial conquest, this original goal may change to non-territorial aspirations over time as a reflection of conditions on the battleground.

This raises the question of which factors would influence the belligerents’ rational cost–benefit calculations about war termination. A foundational article by James Fearon starts from the premise that war is costly and there is less “pie” to be divided after war than before war.18 This raises the question of why rational decision makers are unable to come to a peaceful settlement that does not incur the costs of war. Fearon proposed three rationalist explanations for war: (1) private information and incentives to misrepresent, (2) commitment problems, and (3) issue indivisibilities. According to the first explanation, states would not have private information about their opponents’ resolve or capabilities before the war. Trying to get a better deal at the pre-war bargaining table, states may underestimate their opponents’ capabilities or have greater incentives to misrepresent their own resolve or capabilities, and as a result, states would end up with war. If this is the case, war could allow both sides to learn each other’s actual relative strength or willingness to bear costs, which could give belligerents an opportunity to solve the information asymmetries, leading over time to a revision of war objectives or acceptable terms of settlement, and eventually help them reach a deal for war termination. But states might also have continuous incentives to misrepresent because truthful revelation of resolve and capabilities could allow opponents to develop countermeasures to war plans, and thereby lower their probability of better settlement.

The second rationalist explanation of the cause of war is commitment problems. When one state fears that in the future its adversary will be in a superior position to demand unacceptable concessions, the state will have an incentive to fight sooner (i.e., preventive war), rather than wait for a worse situation where it will be less able to resist such demands. From the perspective of war termination, commitment problem explanations raise the question how war can actually solve the commitment problem and make possible a deal after war which was not possible before war. Possibly, the First World War presents the best example of large-scale preventive war. Germany was attempting to prevent the rise of Russia, while Britain and France were seeking to prevent the rise of Germany. But neither the defeat of Russia nor that of Germany permanently prevented their rise. Rather, preventive war only postpones the rise of a competitor because belligerents allow themselves to be satisfied with a temporary solution. This raises the question of why belligerents may decide to accept a temporary solution. Reiter highlights the importance of commitment problems by focusing on the enforceability of any war-ending agreements. He argues that when one belligerent fears that its adversary might not comply with a war-ending agreement, it is more likely to pursue total victory. Specifically, the victor is more likely to seek to ensure compliance through annexation, occupation, genocide, and/or foreign-imposed regime change. In a case study of 23 decisions about war aims and war termination including the U.S. Civil War until World War II, Reiter finds that doubts about whether the enemy would comply with a war-ending settlement most likely played an important role in 14 cases. Subsequent empirical work on a longer data set by Crisher reinforces this argument.

Domestic Politics

While many scholars of war termination have analyzed the question from the perspective of states as unitary actors, others have emphasized the role of domestic politics. In essence, the outcome of war and the terms of settlement will affect the domestic political balance of power and will make some groups and individuals domestic political “losers” and others “winners.” It will be especially difficult for the government that is losing a war to decide to terminate that war. Under such circumstances, those who want better terms and therefore prefer to keep fighting will face off against those who would prefer to end the war and are thus willing to accept more losses. This domestic political battle is basically over future domestic political power, and it must be resolved before the inter-state war can be ended.

Public opinion about the war also plays an important role in domestic political battle, especially in democracies. There are three main factors that affect public opinion during a war, which can in some cases work against each other. The first is the number of casualties. As casualties increase, support for the war decreases. The second is the war’s objective. If the public believes in the rightness of the war and its likely success, they are likely to become more tolerant of the human costs of war, which could be a good indicator of the nation’s resolve. Studies further suggest that elite debate, as expressed in the media, will shape public opinion about the war.

Third, some scholars have focused on the ways in which public opinion shapes the incentives of incumbent leaders to terminate or continue war. Leaders may have incentives to continue even a costly and unsuccessful war in a “gamble for resurrection” as the only way to stay in office. In addition, leaders sometimes choose the risky option of continued war over settlement in order to avoid severe personal punishment. Domestic political regime type can profoundly affect how leaders react to new information. Goemans argues that leaders of democracies and dictatorships will lower their war aims when they get bad news. In contrast, leaders of oligarchic (mixed or “semi-repressive, semi-exclusionary”) regimes will sometimes increase their war aims when they receive bad news because settlement on losing terms, even a moderate loss, may lead to the overthrow of the regime, the leader’s removal from office, and subsequent significant punishment in the form of exile, imprisonment, or death. 36 In his detailed historical analysis of World War I, Goemans finds support for his thesis in that Germany—a semi-repressive, semi-exclusionary regime—indeed increased its war aims when it became more pessimistic about the war in 1916 and gambled for resurrection in several instances precisely in order to forestall a revolution and to save the monarchy and the kaiser personally.

Non-Rationalist Approaches

While rationalist explanations have dominated much of the discussion of war termination in political science, alternative approaches based on psychological findings have also been influential. A particularly influential strand of this literature focuses on “prospect theory,” which comes from behavioral finance and economics. Prospect theory holds that economic (and political) actors value gains and loss asymmetrically, feeling greater pain at loss of an asset or territory than utility at the gain of the same or equivalent asset or territory. The resulting loss aversion complicates war termination and settlements, especially where territory has changed hands multiple times or in multiple locations, as both sides consider territory that they have controlled at any point in time a possession whose loss is painful to them. When territory is the result of “hard-fought gains” for which blood has been spilled, it becomes even more difficult to accept defeat or to come to a negotiated settlement over a new map.

Nationalism and identity politics can also significantly complicate the decision of leaders to accept defeat even in the face of clearly negative cost-benefit analyses. The appearance of nationalism in late 18th century Europe coincided also with solidification of national borders and an identification of particular geographies and boundaries with the nation (i.e., the creation of the “nation-state”). Some territory takes on particular symbolic value that may override current facts on the ground. For example, the Serbian national mythologizing of the 1389 Battle of Kosovo made control of that territory psychologically important to the Serbian state in the late 1990s even though Kosovo’s population was by then over 90% ethnic Albanian Muslims. This identification only strengthened in the 20th century with notions of self-determination and the rise of decolonization. Although borders are often disputed, the reification of borders as an essential element of national identity—whether existing, historical, or desired—compounds the challenge of loss avoidance in war termination and territorial settlement.


There has been considerable study of negotiated settlement of both interstate conflict and civil wars, including some systematic comparative research as well as many case studies. Several lessons can be drawn from this record.

First, it is normal for negotiations to operate at the same time that conflict is active. The Korean War Armistice was negotiated during some of the most savage fighting of the war and the same can be said of many other conflicts. Indeed, if the battlefield is unsettled, belligerents have an incentive to increase violence in order to gain more territory before a ceasefire, show a credible commitment to continue fighting indefinitely, or force a reluctant opponent to negotiate. Practitioners and scholars often refer to whether the timing is “ripe” for agreement: “Parties resolve their conflict only when they are ready to do so—when alternative, usually unilateral, means of achieving a satisfactory result are blocked and the parties find themselves in an uncomfortable and costly predicament.” The security studies literature focuses in particular on the notion of “mutually hurting stalemates,” in which neither side can easily achieve victory and the costs to both are high. If there is a feasible way out through a negotiated settlement, the mutually hurting stalemate provides a window of opportunity for warring parties to change course; if they do not see a feasible way out through negotiation, in contrast, the result is frozen conflict. The degree of pain from continuing in the stalemate is an important variable and it is particularly likely that the timing will be ripe if one or more belligerents risk a catastrophe such as the loss of a grain harvest, entry into the war of a new party, potential loss of an ally, or severe domestic civil unrest. As Richard Holbrooke wrote about the Bosnia war, “We could not expect the Serbs to be conciliatory at the negotiating table as long as they had experienced nothing but success on the battlefield.” The success of Croat and Bosniak counter-offenses in 1995 made the conflict ripe for negotiation, as the Bosnian Serbs realized they could not expect to take the entirety of their objectives and the Croats and Bosniaks understood that they would be hard put to advance further against the Serb forces.

Second, negotiated settlements often build on a series of confidence-building measures. Incremental steps offer opposing sides the assurance that the other side can keep its word and control its forces. Measures such as delivery of food and medicine, exchanges of prisoners or dead soldiers, or establishment of humanitarian corridors for displaced people to leave areas of conflict may not directly affect fortunes on the battlefield, but they can create good will and they can provide valuable opportunities to develop practical communication and cooperation between opposing forces that can improve chances for success at more difficult tasks, such as keeping ceasefires. 

Third, territorial settlements typically track success on the battlefield, or in Holbrooke’s words, “the shape of the diplomatic landscape will usually reflect the balance of forces on the ground.” While the final agreed border or “line of control” may not exactly match positions on the battlefield, it is typically close and trades in territory are likely to be proportionate. Similarly, seemingly intractable communal conflicts may be resolved through conflict that changes patterns of ethnic settlement. While ethnic cleansing can prolong or exacerbate conflicts for obvious reasons, it can also provide a relatively unambiguous template and rationale for where new territorial lines can be drawn.

Fourth, third-party mediation is a common feature of conflict termination, for both interstate and civil wars, particularly since the end of the Cold War. The UN and certain countries (e.g., U.S., Norway, South Africa) have been active in mediating conflicts and there is extensive evidence that mediation facilitates agreements. There is scholarly debate over whether particular attributes of mediators are especially helpful in concluding negotiated settlements. For example, there is some evidence that democratic countries are more effective mediators due to their desire to establish a reputation for fairness. Surprisingly, there is less consensus on whether it is desirable for mediators to be unbiased—on the one hand, bias can be seen to delegitimize the proposals of mediators; on the other hand, a biased mediator can be more credible in pressuring its preferred belligerent to accept a settlement. However, it is undoubtedly important that a mediator be able to mobile resources to monitor, enforce, or incentivize a settlement. As a result, “Mediation by international organizations (UN and regional organizations) as well as by the USA is correlated with success.”

Once the situation is ripe for negotiation, external actors can provide incentives that expand potential bargaining space by creating the possibility of positive-sum outcomes. Warfare is zero-sum or negative-sum in nature, which substantially shrinks potential bargains between combatants. Economic incentives offered by external parties can effectively address the expected challenges of post-conflict reconstruction and development. Promises of economic aid have facilitated negotiated settlements and ceasefires in a variety of situations in Africa and Asia, ranging from the end of the Cambodian civil war to the breakup of Sudan. In the former Yugoslavia, access to EU markets, aid, and development lending have been powerful carrots for countries to respect the promises they have made to end conflicts and protect ethnic minorities and property rights. Thus, third-party incentives can both facilitate settlements and contribute to their durability. 

Finally, new tools such as digital mapping using geographic information systems (GIS) have become increasingly important in the process of developing territorial settlements ranging from permanent new borders to temporary humanitarian corridors. Digital mapping and improved ability to track patterns of settlement can make it easier (or in some cases harder) to identify defensible or ethnically coherent borders, especially when settlement patterns have shifted and do not conform to existing maps. However, they also interact with existing patterns of property rights and local and national laws in ways that can lead to a gap between what is militarily and politically feasible.


Ceasefires and negotiated settlements constitute important milestones in the resolution of territorial conflicts. However, they are often unstable, either because the root causes of the conflict remain in place or because combatants take ceasefires as opportunities to regroup and prepare their forces for renewed conflict. Several factors affect the likelihood of renewed conflict. For example, the larger the number of states or groups involved in combat, the less stable a settlement will generally be. Duration of conflict and number of casualties, on the other hand, can cut both ways. While longer, bloodier conflicts can harden the positions of belligerents and create incentives for them to overturn settlements seen as unfavorable to them, the sheer costs and exhaustion of long, bloody wars can also support adherence to agreements. Below, we consider factors that have been seen to contribute to greater post-conflict stability.

Deterrence and Balance of Power

It is widely considered that the failure of deterrence is one of the major sources of war onset (e.g., China’s entry into the Korean War in October 1950). Therefore, following conflicts, former belligerents often aim to restore the deterrence between the warring parties in order to prevent future wars and conflicts. Deterrence is most likely to be successful when a prospective attacker believes that the probability of success is low and the costs of attack are high. Thus, deterrent strategies can focus on either lowering the probability of success (e.g., by improving defenses, using natural barriers to create chokepoints, or developing intelligence capabilities that reduce the potential for surprise attack), raising the costs of attack (either by strengthening home defense to inflict more damage on invaders or by punishment strategies focusing on attacker the opponent’s home territory), or both. In this section, we focus on defensive capabilities, which address both costs to an invader and its prospects for success.

There are two main approaches of convincing a prospective attacker that the probability of success is low and the costs of attack are high: internal balancing and external balancing. “Internal balancing” involves efforts to enhance a state’s power by increasing the state’s own economic resources and military strength in preparation for an attack from a prospective enemy.53 “External balancing” involves strengthening and enlarging the state’s alliances and interstate cooperation in order to prevent a prospective attacker from taking an offensive action by demonstrating that the prospective attacker will likely face not only the target state but also its allies. Deterrence based on expectations of alliance support is also called extended deterrence, which is a commitment to deter and, if necessary, to respond across the spectrum of potential conventional and (if applicable) nuclear scenarios in defense of allies and partners. The pre-World War II historical records show that almost all major multiparty wars have resulted from the failure of extended deterrence—i.e., when one major power tried to prevent another power’s attack on its ally—despite some notable exceptions such as the Soviet and U.S. entries into World War II.

Both internal and external balancing can support the durability of a territorial settlement, either by ensuring a balance of power between former belligerents or by raising the costs of conflict to an unacceptable level. Internal balancing may be sufficient to deter attacks across a new border or buffer zone, although even in the case of internal balancing, there is often a role for external partners to provide funding, weapons, or training. In the aftermath of the 2014 Russian takeover of Crimea and the creation of self-government in ethnic Russian areas of Donbas under the Minsk Agreement, for example, U.S. and other NATO countries provided significant aid to upgrade the capabilities and professionalism of the Ukrainian military, although they did not offer formal security guarantees.

In situations where there is considerable asymmetry between opponents, external balancing may be necessary to deter an attack. The alliance structure on the Korean Peninsula is an example. The U.S.-South Korea alliance buttresses South Korea’s ability to wage war and thus to deter numerically larger forces in North Korea that are able to strike Seoul easily with artillery and missiles. Similarly, the China-North Korea alliance provides assurances to North Korea that the costs of a U.S. preemptive attack would be prohibitive. Moreover, the desire of both the U.S. and China not to renew conflict has led them to restrain their allies at key times over the last 70 years. Although support from external powers can prolong or even encourage conflict, they can also be powerful forces in favor of restraint. Despite diametrically opposed interests on the Korean Peninsula and at times considerable mutual suspicions, the United States and China have shared a common interest since 1953 of not getting pulled back into conflict with each other, which has helped to maintain peace between North and South Korea.

Partition and Ethnic Separation

Any territorial settlement must address the issue of where borders should be drawn and how the populations on either side should interact. This is a particularly charged issue in instances of ethnically driven conflict. One commonly proposed solution to ethnic conflict is partition. Partition typically results from civil war, where it can mean either the creation of new international borders (e.g., through the breakup of a multiethnic state or territory) or the creation of new internal borders (e.g., the creation of ethnically coherent autonomous regions) or new patterns of settlement. Partition is less common as a result of interstate conflict, although it is possible to envisage the creation of a new internal conclave in an area that neighbors a co-ethnic country. While partition is particularly salient to civil wars, it can also be applied to interstate wars where existing borders do not track with current patterns of settlement. 

The effectiveness and ethics of ethnic partition are hotly-debated questions in the study of territorial conflict. Some authors have argued that violent ethnic conflicts make it impossible for antagonistic ethnic groups to coexist in the same area and under the same governance. Whereas in earlier times such groups may have lived interspersed within an area in relative peace, with personal relationships dominating ethnic identity, once group-based violence becomes prevalent, the threat posed by being a member of an ethnic group leads to increasing identification with the group and fear of opposing ethnic groups. The result is a security dilemma in which it can be rational to attack members of other groups before one is attacked oneself. According to this argument, the only feasible solution at that point is to separate the warring groups—i.e., partition.

This claim is disputed and empirical evidence is equivocal. As an empirical matter, case selection and definitional differences create considerable confusion as to whether partition is necessary to create durable peace, whether it actually can do so, under what circumstances partition can do so, and whether partition can be engineered in an intentional manner. Alternatives to partition include improved policing, central government targeting of violent groups, and in some cases enforcement action by outside parties such as the UN.

Regardless of its effectiveness in reducing future intercommunal conflict, the history of partitions is often an ugly one, driven by violence and ethnic cleansing. The process of ethnic separation involves a variety of thorny issues, including how to encourage orderly population flows, how to compensate displaced people for lost property, and how to protect minorities who stay in place. Moreover, even apparently effective partitions do not necessarily lead to long-term stability, as seen in the examples of the India-Pakistan split and the creation of autonomous zones in countries ranging from Kosovo to Myanmar. Indeed, it can create new sources of conflict if minority rights within an enclave are not respected. 

Refugee Issues and the Right to Return

International law recognizes refugees’ “right to return” to their homes and property, as articulated in multiple international agreements and declarations, including the Universal Declaration of Human Rights (Article 13), the fourth Geneva Convention (Article 49), and the International Covenant on Civil and Political Rights (Article 12). Most recently, UN Economic and Social Council’s Sub-Commission on the Promotion and Protection of Human Rights endorsed the Pinheiro Principles, which are meant to provide a practical guide to managing refugee issues. The right of return is reaffirmed in the first two paragraphs of Principle 10:

10.1 All refugees and displaced persons have the right to return voluntarily to their former homes, lands or places of habitual residence, in safety and dignity. Voluntary return in safety and dignity must be based on a free, informed, individual choice…

10.2 States shall allow refugees and displaced persons who wish to return voluntarily to their former homes, lands or places of habitual residence to do so. This right cannot be abridged under conditions of State succession, nor can it be subject to arbitrary or unlawful time limitations.

While some refugees are able to successfully return to their homes after famines or fighting based on political conflicts, however, return of ethnic minorities is much rarer in practice, particularly to regions in which they would constitute a minority. Return of ethnic minorities to regions in which they constitute a majority is more common, but even then many will not repatriate due to perceived lack of protection from a central government controlled by the groups that drove them out in the first place. Post-conflict settlements that include regional autonomy or the long-term presence of international peacekeepers and legal advisors improve that situation only slightly.

The example of Bosnia, which is often deemed a successful example of ethnic minorities’ right of return, is instructive. While refugees have returned en masse to regions under control of their own ethnic group under the federal system of government, few have returned permanently to areas in which they are minorities. (This is particularly true of Bosniaks with property in Republika Srpska and Serbs with property in the rest of the country.) The post-conflict settlement, with support of international peacekeepers, has ensured rights of ownership; however, most ethnic minorities have returned to their properties just long enough to sell them (often at a loss) to members of the ethnic majority. Similar stories can be told for Croatia, Iraq, Abkhazia, and others.

The impact of right of return on long-term stability is perhaps most familiar in the case of the Israel-Palestine conflict, where the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) states that a total of 5.9 million people currently qualify as refugees. The Palestinian refugee situation is multi-generational, growing from about 700,000 refugees in the 75 years since UNRWA was created. More than 1.5 million still live in 58 refugee camps spread across the Israeli-occupied territories, Jordan, Lebanon, and Syria. The right of return has been a constant sticking point in negotiations between Israel and Palestinian representatives and has consistently contributed to the derailment of final status negotiations.

The Israel-Palestine refugee situation is unique in many ways, including that the number of self-identified Palestinians approaches the number of Israeli Jews. This is one reason that Israeli leaders refused to recognize Palestinian right of return at the time of partition in 1948, a position that holds to this day. At the time, Israeli leaders anticipated that the attachment to the land would decline as refugees settled in other countries and as new generations were born. This presumption proved to be wrong on two counts. First, as noted, a large proportion continued to live in refugee camps. Many others remained stateless even as they settled in neighboring countries, often for extended periods of time, due not only to desire to return to their property, but also the unwillingness of host states in the region to offer them citizenship. Second, Palestinian identity has been built partly on the notion of a sacred attachment to the land, a sentiment that has not abated even across generations.

The role of UNRWA is unique to the Israel-Palestine situation. It actually predates the creation of the UN High Commissioner for Refugees (UNHCR), which is the UN body responsible for refugee issues everywhere else in the world. To be sure, UNRWA camps are not the only long-term refugee camps in the world, but as a unit they are the longest-standing, most populated, most permanent camps. UNRWA operates as an extensive public-service organization, offering an extensive network of schools that enroll over half a million children, as well as hospitals and infrastructure. In the camps, UNRWA operates as a de facto government, while in areas controlled by the Palestinian Authority and Hamas, it advises on governance. It even runs schools in East Jerusalem, which has been excluded from Palestinian self-governance arrangements.

UNRWA is donor-funded, with nearly half its budget coming from the U.S. and Germany. In order to maintain funding, it seeks to be apolitical. However, it has been criticized by U.S. politicians as prolonging the conflict and redefining refugee status beyond standard definitions. UNRWA schools have also been criticized as perpetuating a Palestinian national identity that is hostile to Israel and that reinforces the importance of the right of return and the sacredness of Palestinian lands. This has led to periodic confrontations with U.S. policy makers, including a 2-year suspension of funding in 2018-20. In the current Israel-Hamas conflict in Gaza, there have also been accusations that UNRWA-salaried workers were active Hamas militants, suggesting that UNRWA may have wittingly or unwittingly supported violence.

There is, of course, considerable debate regarding the ethical and political justifications and consequences for Palestinian right of return and UNRWA’s role in running permanent refugee camps, reinforcing territorial-based national identity through schools, and maintaining refugee status over many decades for an expanding population. As a practical matter, however, it has been argued that this has made a settlement over final status more difficult and has locked many individuals into lives as refugees rather than as diaspora building lives abroad.

The right of return and handling of refugees are important elements in the settlement of any territorial conflict. While international law, most recently spelled out in the Pinheiro Principles, mandates an individual right of return, in practice most refugees of ethnic conflict do not return to their previous homes. Politically, however, attachment to homeland can prolong conflicts, especially where resettlement in safe areas and compensation are not made available.

Strategic Geography

It is well established in security literature that certain physical features make borders more defensible. Mountains, deserts, and bodies of water such as rivers, lakes, and seas make aggression more difficult, costly, and uncertain. Offensive action and occupation of unfriendly territory, which typically requires substantially more manpower, firepower, and logistical capability than defense at the best of times, is further challenged by such features. Defenders can focus on chokepoints (e.g., bridges, ports, and mountain passes), whereas attackers face heightened vulnerability and longer, more challenging supply lines. Despite the impressive capabilities of modern air power, missiles, and artillery, taking and holding territory requires ground forces to physically eliminate defenders. Geographic features therefore adjust the effective balance of capabilities in favor of defenders. Geographic challenges also reduce opportunities for surprise attacks. This reduces the incentive for opponents to carry out preemptive attacks in uncertain situations, which reduces the likelihood of conflict based on miscalculation or accident.

The obverse is equally true. Borders that are not based on defensible geographic features are more vulnerable to reignition of conflict, since the lack of physical impediments lowers the costs of invasion significantly. A classic example is Poland, which has spent considerable time as a battleground or occupied territory, and whose territorial integrity in the post-WWII period has been maintained via arrangements with external powers—initially through acquiescence to Soviet leadership in the Warsaw Pact and subsequently through NATO membership.

The absence of geographical barriers can also increase the likelihood of preemptive war, even for a state that is satisfied with its existing borders. The 1967 Six-Day War is a classic example of preemption caused by Israel’s sense of vulnerability to enemies across easily-traversed borders. It is instructive that Israel chose to retain control for many years even of territory (such as Egypt’s Sinai Peninsula) that it did not claim as its own (unlike the West Bank and Gaza), in order to make future attacks more difficult. In other words, it sought to replace natural barriers with unilaterally imposed buffer zones.

Buffer zones can be either negotiated or unilaterally imposed, and may or may not be monitored or enforced by third parties such as a peacekeeping operation. Perhaps the most famous negotiated buffer zone is the Korean DMZ, which cuts across the peninsula at a consistent width of 4 kilometers. As part of the armistice agreement, all settlements except for two small villages were relocated from the zone, which has paradoxically become a de facto nature preserve (despite being filled with anti-tank and anti-personnel landmines). Large-scale relocation of villages and cities is often not feasible, however. Moreover, patterns of social and economic interactions may inhibit the ability to create a full separation. In Cyprus, the UN Buffer Zone (also known as the Green Line) varies in width depending on patterns of settlement, ranging from just a few meters in some highly populated mixed-ethnicity cities like Nicosia to several kilometers. In wider areas, the buffer zone is often populated (sometimes by both Turkish and Greek Cypriot villages), but formally demilitarized. While movement of people and goods across the Green Line was more heavily restricted in its early years, in 2004 the Turkish Republic of Northern Cyprus opened its borders, resulting in considerable traffic across the line. Still, commerce remains limited for both legal and practical reasons. Israeli buffer zones in the occupied territories of the West Bank and Gaza have also generally been porous. The territories themselves are formally demilitarized (although the current Israel-Gaza conflict demonstrates that at least in Gaza demilitarization was a fiction) and various walls and checkpoints have been installed. Israeli forces have periodically created or expanded unpopulated buffer zones by destroying buildings and settlements. However, there has been considerable traffic across internal borders, which has facilitated large-scale trade and movement of people (especially Palestinian labor). Depending on security and political conditions, these passages can be made more or less open. In heavily populated areas, it will often be more practical to create relatively narrow and permeable buffer zones that account for existing patterns of settlement. However, permeable borders offer less certainty against military attacks than a Korean-style depopulated DMZ, whether they are unilaterally imposed (as in the Israel case) or negotiated (as in the Cyprus case). 

Finally, one important finding in the literature on post-conflict borders is that actual negotiated territorial settlements usually fall along some sort of historical border. This may seem surprising, given the importance attached to drawing borders that are defensible from a geographical standpoint. However, previous borders can provide a useful focal point in negotiations that makes it easier for them to come to an agreement. As one study argues, “when states choose new borders they use previous administrative frontiers to solve a difficult short-term bargaining problem and a long-term coordination problem.” Historic borders can also provide a focal point for ethnic cleansing and partition.

Ethnic Resettlement

In many post-conflict situations, strategies of partition and creation of buffer zones build upon ethnic resettlement, whether done with the express intent of eliminating a particular group from a geographic area (ethnic cleansing) or resulting from individual or group decisions to leave the area due to fears of discrimination, persecution, or violence. While in principle the threat of violence or discrimination may be sufficient to encourage large-scale population movements, in practice actual violence is common.

Forced ethnic resettlement can be driven by genocidal violence, as occurred in Bosnia. Although war crimes were documented on all sides, the worst atrocities were associated with the forces of the Republika Srpska, at least partly because they were by far the best armed and organized of the ethnic militias in the country prior to 1995, due to the active support of the Serbian military across a long and porous border. Bosnian Serbs’ efforts to expand their territorial control and eliminate non-Serbs from within the growing borders of Republika Srpska included massacres and the use of sexual violence against civilians, as well as abuse and executions of prisoners. In addition, many Bosnian villagers were successfully encouraged to self-organize and carry out violence against their neighbors. A Congressional Research Service report states that “Most observers believe that most war crimes committed by the Bosnian Serbs from 1992 until the end of the war in 1995 were not unplanned, scattered excesses by a few soldiers, but a key aspect of the political and military strategy of the Bosnian Serb leaders… This policy was aimed at creating a territorially compact, ethnically ‘pure’ Serb state … which would then be united with Serbia and Montenegro and an ethnically-cleansed region carved out of Croatia.” Thus, the scale and effectiveness of ethnic cleansing was enabled not only by a chauvinistic ideology of Serb nationalism that dehumanized Muslims and Croats, but also by the substantial resources of Serbia, the co-ethnic nation-state that supplied Bosnian Serb militias and vigilante groups and whose protection allowed them to operate with impunity.

Initial acts of violence are not always perpetrated by a national majority. In Croatia, for example, Serbs (a national minority) in the majority-Serb region of Krajina sought to secede by force, with the support of the neighboring government of Serbia. Following several years of conflict, the Croatian government mounted Operation Storm in 1995, defeating the armed Serbian forces. As documented by the International Criminal Tribunal for the Former Yugoslavia (ICTY), there were extensive war crimes on both sides of the fighting supported by the top leaders of Croatia and Serbia. In response to both Croatian government violence and fear of punishment for their own actions, many Serbs fled the region following the success of Operation Storm. The Croatian government took the opportunity to take over many homes and property and to distribute them to ethnic Croats, including refugees from neighboring Bosnia. Return was made difficult for ethnic Serbs, meanwhile, especially for those who had served in the armed resistance to the Croatian government or who had been tried in absentia as war criminals. While ethnic Serbs were eventually given the right to return and reclaim their property, judicial proceedings were time-consuming and observers noted that even if they were successful in regaining their property rights, many original owners reported “finding their homes looted even to the point of having tiles, sinks, bathtubs, and toilets removed.”  Those who returned encountered discriminatory laws until EU pressure led to more minority rights, but even today Serbs in Croatia experience discrimination and marginalization. As a result of the inhospitable situation, the population of Serbs in Croatia dropped from 12% in 1990 to only about 4.5%. 

One recent example of massive ethnic resettlement occurred in Nagorno-Karabakh, where Azerbaijan retook control of the Armenian enclave there (the self-proclaimed Republic of Artsakh) in September 2023 after more than thirty years of confrontation and conflict between Azerbaijan and Armenia. According to news reports, over one hundred thousand people (80% of the ethnic Armenian population) fled the region in the space of a week.83 News reports at the time showed caravans of cars and trucks heading from Nagorno-Karabakh to refuge in Armenia. While the Azerbaijan government declared that Armenian residents could stay and receive all the protections of Azerbaijan citizenship, the vast majority of those residents chose to leave, even in the absence of mass atrocities against civilians.


Peacekeeping operations (PKOs) are a common feature of post-conflict settlements, particularly where there is no clear buffer zone or geographical separation between belligerents. In principle, PKOs are put in place and maintained at the request of both (or all) belligerents. There are several types of PKOs. “Observer missions” are unarmed and have responsibility only for monitoring adherence to ceasefires and other agreements. In “traditional” PKOs, personnel are lightly armed but are only authorized to use arms in self-defense. “Multidimensional” PKOs include some combination of governance, election training/monitoring, human rights monitoring, police training, etc. in addition to monitoring of security agreements. Another distinction is between UN PKOs (the most studied and most professional multilateral PKOs) and those mounted by other regional organizations such as the African Union or the Organization for Security and Cooperation in Europe (OSCE) or by individual states. In the post-Cold War period, unarmed OSCE missions have been particularly active in monitoring ceasefires and capacity building in a variety of post-Soviet and post-Yugoslav conflicts. A final category in some of the literature is “enforcement,” which is externally imposed, as in Kosovo. The rise of the norm of “responsibility to protect” has empowered UN-sanctioned enforcement missions in dire human rights situations in the post-Cold War era, but enforcement can also be imposed by individual powers or coalitions. 

A consistent finding of studies of territorial conflict is the benefit of third-party peacekeeping forces in reducing conflict between neighboring belligerents (measured as “peace duration after war”). While early studies found the strongest evidence for UN multidimensional PKOs, more careful specification and quantitative analysis has yielded the result that all forms of consensual PKOs have been very effective at doing so. These effects hold across a variety of types of territorial conflict, including both interstate and internal conflicts as well as conflict driven by causes ranging from ethnic to political to religious. Indeed, the case for the effectiveness of peacekeeping operations has strengthened over time despite more rigorous quantitative testing, with a comprehensive recent analysis concluding that “PKOs increase the duration of post-conflict peace, reduce the lethality of ongoing conflicts, increase the chances of conflict ending, and prevent contagion to neighboring countries.” One caveat to this general finding is that non-UN humanitarian enforcement actions do not consistently have positive effects on human rights even if they contribute to the stability of post-conflict settlements.

The efficacy of PKOs may have changed over time. UN-sanctioned humanitarian enforcement actions expanded dramatically both in number and in scope (and budget) after the Cold War, as U.S.-Russia rivalry subsided. In more recent years, it has been harder to secure cooperation among the U.S., Russia, and China at the UN Security Council. This may affect PKO effectiveness directly; it also raises the possibility that a major power may continue to support a particular belligerent despite the presence or attempted presence of peacekeepers in a given situation. As noted above, external support of belligerents tends to prolong conflicts. 

It is also important to note that mutual consent of belligerents is a precondition to the effectiveness of most PKOs. For example, the UN Emergency Forces (UNEF) in the Sinai Peninsula had helped to keep the peace between Israel and Egypt for over a decade after the 1956 Suez Crisis; however, the removal of UNEF at the request of Egypt allowed for mobilization in the region that eventuated in the Israeli preemptive attack in the Six Day War. More recently, the Bosnian Serb massacre of Bosnian Muslims in the declared “safe area” of Srebenica in 1995 occurred despite the presence of a lightly-armed UN observer mission, which did not intervene to try to prevent the slaughter. The Bosnian Serb military rejected the externally-imposed safe area, rendering the observers impotent. Only after NATO began a campaign of airstrikes and introduced a new Rapid Response Force to protect UN peacekeepers did the Bosnian Serb military respect their authority. At that point, the UN PKO effectively became a UN-NATO joint enforcement action with the military capability to enforce agreements and to keep forces separate from each other and from civilians from other ethnic groups. This proved essential to the success of the Bosnian settlement, which continues to hold to this day and has allowed for free transit by all ethnic groups across the entire country.

External Incentives and Guarantees

Post-conflict stability can also be improved through a variety of external incentives and guarantees. The Camp David Accords, for example, were supported by an agreement by the U.S. to provide long-term bilateral military aid to both Egypt and Israel. In general, economic aid can improve the capabilities and domestic support for governments that respect peace agreements and ceasefires, while the threat of withdrawal for non-compliance can be a powerful incentive. This is especially true in lower-income countries and where state capacity is low. Military aid can also contribute to stability when it is provided to a weaker belligerent in order to support a balance of power.

The prospect of membership in regional or global organizations can also be a powerful incentive for compliance. For example, in the aftermath of the violent breakup of Yugoslavia, Croatia was offered the opportunity to join NATO and the World Trade Organization on the condition that it improve human rights and accept requirements of transitional justice. Later, its successful bid to join the European Union required it to agree to protect the property rights of former residents (many of them Serbs who had left under pressure) and to accept the jurisdiction of the European Court of Justice.

Explicit security guarantees are another method of securing borders. The strongest of these are military alliances.92 The impressive stability of the Korean armistice has been ensured not only by the creation of a buffer zone in the DMZ, but also by the establishment of the U.S.-South Korea alliance. (The Sino-North Korean Treaty of Friendship, Co-operation, and Mutual Assistance on the other side of the border may also contribute to this stability.) As an alternative, external powers can mutually agree to respect newly-established borders, sometimes in the form of formal declarations of neutrality, as in the case of interwar Belgium. These pledges proved ineffective when Germany rolled through Belgium on its way to invade France in 1940. Perhaps the most well-known recent security guarantee of that sort was the Budapest Memorandum of 1994, in which Russia, the U.S., and other countries agreed to guarantee the territorial integrity of Ukraine in exchange for its relinquishment of its Soviet-era nuclear weapons. While initially seen as a triumph of diplomacy, the Russian seizure of Crimea and support of separatists in Eastern Ukraine in 2014 and its 2022 full-scale invasion have raised doubts about the feasibility of non-alliance security guarantees.


While a detailed post-conflict reconstruction is outside of the scope of this paper, economic and political developments within the territories of all parties to a conflict can have a profound impact on the durability and quality of peace.

Features of Successful Post-Conflict Governance

Because most studies on post-conflict reconstruction focus on developments in the state or region in which conflict occurs, we focus on those aspects as well. However, it is important to bear in mind that political and economic conditions of aggressor states are also important to post-conflict stability. As the war initiation literature shows, aggression is more likely when a state or political movement has more access to material resources (capability), when domestic political standing of leaders is either unchecked (narrowly-based authoritarianism) or dependent on nationalist voices, and where countervailing societal or economic preferences are excluded from the political process. Economic sanctions, integration with regional and global economies, and inclusion or exclusion from regional or global organizations can change those dynamics, although not always in predictable ways.

Both politically and economically, governance is of great importance to the success of post-conflict settlements. Problems of corruption and inefficiency reduce the willingness of foreign aid agencies, potential foreign investors, and even diaspora remitters to provide needed funds, even as they reduce the positive impact of those funds that are provided. Corruption also reduces domestic confidence in government, potentially leading to political divisiveness and instability. As one review of case studies across three continents concluded, “Greater electoral competition, institutional complexity and the entry of new players and sources of ready cash—including foreign donors, natural resource exports and organized crime—are driving new conflicts, and alienating the public from their rulers…” Other aspects of governance are also important in post-conflict societies, especially equitable treatment for ethnic groups or regions. In intra-state territorial conflicts, inequitable treatment can lead to renewed irredentism and the possibility of renewed conflict as the foreign opponent may seek to defend the interests of its allied groups (whether on the basis of ethnicity, language, religion, or national sentiment). Finally, poor governance weakens the ability of states to develop their own capabilities to defend against or defer future attacks, both by reducing economic potential and compounding political divisions.

For all these reasons, external supporters of post-crisis states have emphasized the development of effective governance and respect for human rights—as seen, for example, in efforts at post-conflict reconstruction and democratization in states as diverse as Afghanistan, Bosnia, and Cambodia. In these cases, there are typically multiple actors, ranging from UN agencies and multilateral development banks to national aid agencies and regional organizations, seeking to provide technical assistance, conditional aid, and monitoring. In post-conflict states in Europe and the post-Soviet space, the OSCE has played a special role due to its status as a consensus-based regional organization. While the multiplicity of external actors makes for greater provision of resources and technical assistance to new post-conflict states, it can also make for confusion and venue-shopping by the new government, as various agencies bring differing agendas to the table and may work at cross-purposes. Not surprisingly, given that post-crisis states have experienced considerable trauma, dislocation, and physical damage, good governance and protection of human rights often remain elusive, despite the best efforts of domestic and international actors. Prospects for success are best in countries with traditions of effective governance and where dislocations were relatively limited, such as Croatia. However, substantial support for good governance and human rights—even when success on its own terms is limited—does appear to reduce reemergence of conflict, even in seemingly unlikely cases such as Bosnia, Cambodia, and Kosovo.

A key element in the creation of a governance regime in post-conflict states is the creation of a new constitution. Constitutions not only act as the basic law and justification for government institutions and procedures; they also reflect complex political deals among major political groups. As one author writes, “constitution-making is considered as a healing process in protracted conflicts, and also as a political and legal map of building a peaceful and cooperative political culture between rival groups.” Thus, scholars and practitioners see the creation of a new constitution as ideally a consultative and deliberative process. The particulars of constitutions are also important to post-conflict governance and politics. Power-sharing among ethnic groups, for example, may be guaranteed at the national level, via varying levels of regional autonomy, or not at all. Authority may be highly centralized or dispersed to lower-level units such as provinces, “federations” (as in the Bosnian case), municipalities, or autonomous zones.  Constitution-writing is by no means a guarantee that post-conflict societies will be well or fairly managed or that human rights will be respected. However, having a constitution that is considered legitimate by a broad range of social and political actors is seen as a necessary, albeit not sufficient, condition for establishing capable and legitimate governance—or at least for reducing the likelihood of future conflict among the former belligerents.

Some post-conflict settlements have included efforts at transitional justice, either through international courts (for example, the International Criminal Tribunal for the former Yugoslavia, or ICTFY), domestic courts, and/or truth and reconciliation commissions. Evidence seems particularly strong for the usefulness of truth and reconciliation commissions (see, e.g., Chile and South Africa), but they are politically difficult to implement and can challenge fragile political settlements. External players such as the UN may facilitate transitional justice efforts. Some external funders condition their economic support on such efforts: perhaps most notably, the EU made cooperation with the ICTFY an absolute condition for future EU membership, a major goal for all the former Yugoslav states. Indeed, Serbia’s official National Program for EU Integration in 2009 stated that it was cooperating with the ICTFY “primarily […] in the context of acceptance, upgrading and respect of the values and rule of law as recognized in European countries.”

Role of International Actors in Constitution-Making

Constitution-making has become a focal point of much of the policy and academic analysis of peacebuilding and statebuilding in post-conflict societies. Since the end of the Cold War, international involvement in constitution-making has become the norm. Starting with the remnants of the former Yugoslavia, it has become common wisdom that constitutions—and the process of creating and approving them—are essential to the stability and fairness of post-conflict states and that the UN and other international actors have a legitimate and important role in shaping them. From this has grown a large body of advising by agencies ranging from the UN to bilateral and regional bodies such as the U.S. and European Court of Human Rights. In addition, there has developed an ecosystem of intergovernmental and non-governmental organizations that work with the UN and donor governments to support constitution-making and peacebuilding.

International involvement in constitution-making has been critiqued in various ways. Some raise concerns that it is a type of neo-colonialist civilizing mission,104 but most focus on the ways in which ham-handed imposition of pre-designed constitutional elements can be counterproductive. Early efforts at externally-driven constitution-making (e.g., in Bosnia-Herzegovina, Iraq, and Timor-Leste) often proved counterproductive and were criticized as “ad hoc” and not taking “appropriate consideration of the range of options and comparative experiences.” More specifically, critiques of highly internationalized constitution-making processes have included excessively tight timetables, insufficient public participation, excessive focus on elites and combatants, excessive focus on technical aspects instead of political settlements, and undervaluation of the importance of national “ownership” and building national capacity. All of these critiques point to the fundamental challenges associated with achieving broad agreement on power-sharing and human rights; moreover, no constitution can guarantee rule of law or good governance. Ideally, however, international involvement can help domestic actors understand the constitutional options available to them as well as how they have worked in practice in other instances.

As a result, international involvement in constitution-making has become highly codified—for example, the UN-affiliated international organization Interpeace has produced a detailed, 367-page guide that extensively details its understanding of procedures from sequencing to timelines to public participation to administration to adoption to implementation. In 2009, the UN Secretary General issued its first Guidance Note on UN Assistance to Constitution-Making Processes, which was most recently updated in 2020. UN and other international supporters of rule of law and constitution-making adhere to a potentially contradictory agenda of supporting national ownership and local context on the one hand and demanding adherence with certain universal principles on the other hand. In particular, these agencies and donors expect that constitutions will meet international norms of human rights, democracy, and inclusion of minority voices. Protection of human rights in post-conflict societies is always challenging, and UN missions in support of constitution-making have increasingly sought to create mechanisms outside of legislative processes to protect them, for example via “advocacy for and capacity building of national human rights institutions (NHRIs) with a mandate to monitor respect for rights embedded in new constitutions.”

While the substance of constitutions is understood by all analysts to be important, it is also understood that there are many ways in which interest representation and protection of human rights and minority rights can be protected. For this reason, there has been considerable focus on the process by which constitutions are created. One early study argued that “the choice of procedure does not really matter much. More representative processes may yield better results in contexts where the level of violence is relatively low; the evidence is not overwhelming, however.” More recent scholarship and practice, however, emphasizes the importance of a consultative process for constitution-making, arguing that long and well-designed deliberative processes improve trust and acceptance among parties (including former combatants). For example, it is widely agreed that interim constitutions can improve the development of consensus on a final constitution. In the constitution-making process itself, practices such as veil rules, public consultation, and referendums improve the legitimacy and staying power of new constitutions in post-conflict states.

Studies also suggest an important role for international interventions in some circumstances. One point that is made in UN and other international organization manuals and studies is that protection of human rights and minority rights contributes to the durability of post-conflict stability and peacebuilding. Therefore, they strongly advocate—or in cases of complex peacekeeping operations, require—them as a matter of policy. In addition, although unilateral imposition of a constitution and legal institutions is universally seen as problematic, international actors can sometimes break stalemates or introduce new alternatives or incentives that can create successful agreements: as one study from the International Institute for Democracy and Electoral Assistance (a prominent player in the post-conflict constitution-making space) notes, “Intergovernmental organizations, and sometimes specific countries or country coalitions, can offer the space for parties to engage in dialogue and negotiations. Intergovernmental organizations may also have the convening power to broaden the negotiation table and include actors with a particular interest in a country.”

Regardless of the rationale, it is hard to imagine a post-conflict constitution-making process that does not involve the UN and other experienced rule of law-promoting organizations. This is true both because of the rising legitimacy and technical expertise of these groups, but also because of the necessity of multilateral economic support for post-conflict states, and in particular newly-created states. The main exception would be unrecognized quasi-states, where the new entities are essentially supported by a single combatant and the international community is held at arm’s length.

Protection of Minority Groups

Many conflicts at both the international and domestic levels are at least partly ethnic in nature. Because patterns of ethnic and ethnolinguistic settlement seldom coincide neatly with official borders, most states in the modern world are multiethnic. This basic fact raises the necessity of developing clear policies for how minority groups will be accommodated or discriminated against in terms of representation, education, and participation in the economy and society. Moreover, since settlement patterns for many ethnic groups cross state borders, seemingly domestic policies toward minorities can have significant international implications, especially if the proportions of particular groups in two countries differ. For example, the primary ethnolinguistic groups in both Malaysia and Singapore are Malays, Chinese, and Indians, but Malays are the plurality in Malaysia while Chinese are a majority in Singapore. Historically, many bilateral tensions have been driven by the differential treatment of Malays and Chinese in the two countries. In the former Yugoslavia, treatment of ethnic Serbs in Croatia, Kosovo, and Bosnia is of great concern to Serbia, as is the treatment of ethnic Croats in Serbia to the Croatian government. A similar dynamic has been observed in the states of the former Soviet Union, where Russia has positioned itself as defender of the interests of ethnic Russians. Indeed, part of the official justification for the annexation of Crimea in 2014 was based on the claim that “the Russian people have become one of the largest divided nations in the world, if not the largest,” leaving Russia with the responsibility of protecting their interests no matter where they resided.

Protection of minority groups has become increasingly prominent in international law and in the advice of international organizations, ranging from the United Nations to the OSCE to the European Court of Justice. The implementation of minority policies has been particularly salient in states that have experienced ethnic conflict, especially when the international community has been invited or chosen to intervene through mediation, peacekeeping, legal advising, and constitution writing. Minority protection can be implemented in the form of laws against discrimination or group-related violence or hate speech. Legal status is another part of the toolkit—for example, Serbs are designated as a “constituent nation” in Kosovo and Serbian is an official language; in Croatia, in contrast, Serbs are classified as a recognized minority. Similarly, Kosovo offers specific rights to all minority groups to speak their own language and express their own cultures, whereas Croatia offers more limited linguistic and cultural rights.

The notion of “autonomy” is central to many of the conflicts themselves, as well as to proposed solutions. As one author notes, the OSCE and other international organizations “have attached particular importance to autonomy as a conflict management device and have brought pressure on governments to concede, and on minorities to accept, autonomy as a suitable compromise.” Autonomy as a mechanism of protection of ethnic minorities can take multiple forms. Federalism is one approach that has been advocated and used in a variety of post-conflict situations, such as in Bosnia. An alternative is regional autonomy, in which a particular region is empowered to implement significantly different rules from the rest of the country, while recognizing the authority of the central government and accepting limitations on its actions (and, in many cases, remaining reliant on the central government for fiscal resources). Varying levels of regional autonomy are a common strategy in many countries, from the Philippines (e.g., Autonomous Region of Muslim Mindanao) to Russia (e.g., Republic of Ingushetia) to the United States (e.g., Puerto Rico) to China (Hong Kong and Macau). Reserves (or “reservations” in U.S. usage) for indigenous peoples offer high levels of autonomy within a geographical area on the basis of ethnicity or tribal membership. Less formally, decentralized governmental systems that give more power to local areas relative to the central government can offer minority groups effective autonomy if they live in concentrated areas.

In place of or in addition to territorial autonomy, some states offer nonterritorial autonomy—i.e., collective rights to an ethnic group that are not attached to place of residence, often because the group does not constitute a majority in any specific region. For example, Taiwan reserves a small number of legislative seats for indigenous politicians. By Lebanese custom (but not law), the president is a Christian, the prime minister is a Sunni Muslim, and the speaker of the parliament is a Shiite Muslim. Belgium has allowed linguistic councils power over cultural and educational policies. Such nonterritorial autonomy can be in the form of shares of legislative seats or government positions, voice on particular issues, or even veto rights in particular policy areas. Autonomy solutions appear to be most likely to occur during regime changes, when the international community is involved, where there are reasonably strong traditions of democracy and rule of law, where the negotiating process ensures meaningful participation from minority group members, where autonomous regions and populations are relatively small, and where there are meaningful networks of interest and cooperation between groups.

While autonomy can effectively resolve ethnic disputes and ensure protection of minority rights, governments often resist it out of concerns that it might lead to secession, weaken the capacity and decisiveness of the central government, create resentment among other segments of the population, or encourage other minority groups to demand their own autonomous rights. In practice, there are apparently successful examples in which autonomy has contributed to long-term stability (e.g., Quebec or various internal Russian republics) but also cases that resulted in severe conflict (e.g., Chechnya in the 1990s) or even led to state dissolution (e.g., Bangladesh, Kosovo). In some cases, autonomy may be seen as an intermediate step on the way to a negotiated permanent solution, but it is not guaranteed that a satisfactory permanent solution will be arrived at (arguably the case for Israel and the Palestinian Authority). Weak state capacity in an autonomous region can also exacerbate grievances on the part of both the minority and the central government. Another reason why autonomy may fail is the simple fact of continued grievances among contending groups. And autonomy agreements can be complex, overlapping, and in some cases perhaps even unworkable. Therefore, while autonomy agreements can be useful in fashioning compromises among conflicting parties, it is important to avoid excessively complex or inflexible autonomy mechanisms just in order to achieve short-term compromises.

The role of the international community is particularly notable, as both liberal notions of individual and group rights as well as various forms of power-sharing have become part of the standard toolkit for conflict mediation and post-conflict state-building efforts by major international organizations. Moreover, international organizations can bring important resources to the table, such as peacekeeping forces, reconstruction funding, and technical assistance. For minority protections such as non-discrimination and property rights, the development of an effective court system is seen as essential, and is often an objective of international peacekeepers and aid agencies; this has been a challenge in the former Yugoslav states. In some cases, such as with ethnic Serbs in Croatia and Kosovo, or ethnic Russians in post-Soviet states, the need to appease a powerful neighbor with an interest in a particular minority group can be a powerful incentive to protect that group as well.

Language Policies in Multiethnic Territories

Language policy can be a major challenge for states and ethnic communities in multiethnic territories. Language policies involve a variety dimensions, including the designation of official languages, the rights of linguistic minorities to manage their affairs or defend themselves in court in their mother tongue, and the language of instruction in schools. As one scholar has put it, “In modern nation states language policy and territorial power are closely linked, both when we see power-sharing arrangements between the national/ethnic majority and minority, and when central government denies such minority territorial claims.”

A number of international agreements have offered guidelines for dealing with the rights of linguistic minorities. The 1948 Universal Declaration of Human Rights prohibits discrimination based on language and the 1954 International Covenant on Civil and Political Rights (Article 27) avers the right of “persons belonging to … minorities …to use their own language.” In Europe and the former Soviet space, the OSCE called for protection of minorities in the 1990 Copenhagen Document and 1992 Helsinki Document, while the Council of Europe issued the European Charter for Regional or Minority Languages (ECRML) in 1992 and the Framework Convention for the Protection of National Minorities (FCNM) in 1995. In Europe, the 1950 European Convention on Human Rights also prohibits discrimination based on language and the European Court of Justice has issued a variety of rulings based on the principle that linguistic minorities should be able to operate in their own languages.

The principles on which language policy is based can be either “personal” (allowing individuals the choice of the language of education or official business) or “territorial” (prescribing the use of a language in a given geography).126 Territorial language rights are more common where use of a particular language is concentrated in a particular area. Territorially-based policies can also be easier to administer, particularly when it comes to the primary language of education or the language of government administration, although mixed patterns of settlement can complicate the question of which minority languages are privileged in a particular location.

Language policy is deeply and inherently political. Despite the existence of international legal guidelines and agreements that valorize the preservation of linguistic diversity, language policy in actual practice is often an instrument of nation-building. Particularly for newly-independent states and newly-autonomous regions, authorities will often promote the “titular language” of the dominant group (i.e., the language that is identified with the dominant group—e.g., Albanian in Kosovo, Slovenian in Slovenia). In some cases, particularly in the former Soviet states, the titular language has (perhaps surprisingly) not actually been the most commonly spoken language in the country or even within the dominant group, as seen in the prevalence of Russian in official and common usage in states like Estonia and Ukraine, even among those identifying as ethnically Estonian or Ukrainian. Such a situation can actually increase attempts to impose the titular language, especially if a new state is seeking to differentiate itself from the state of which it was formerly a part. As a 2003 study of language policy in transition states notes, “The assertion or reassertion of a titular language, however, looks quite different depending on the relative demolinguistic sizes of the national majority, the national minority and, where applicable, the kin-state with which the national minority has close links through language, history or culture.” The same study argues that most cases in which transition states have adopted robust minority language have “arisen as a result, not of good-faith democratic negotiation, but of civil war in which the minority simply seized the levers of power (as in Bosnia, Kosovo, Abkhazia or Nagorno-Karabakh).”

Ethnically-based nation-building efforts seek to build a language hierarchy. In addition to establishing an official language or languages, unfavored languages can be stigmatized or marginalized. In dealing with closely related languages, exclusive policies can follow two opposing options. One is to dismiss the unfavored language as merely a “dialect” or “patois” that is an impure version of the favored language. This was seen in Soviet-era language policy in Ukraine, for example. The opposite option can be seen in present-day Serbia and Croatia, where the language formerly known as Serbo-Croatian in Yugoslavia has been bifurcated into Serbian (written in Cyrillic) and Croatian (written in Latin script), with both countries making the effort to accentuate regional differences and to move away from the convergence that was encouraged in Yugoslavia through standardization by accentuating regional differences. In Moldova and its breakaway unrecognized quasi-state of Transnistria as well, the use of Cyrillic vs. Latin script has been a key legal differentiator between Moldovan and Romanian.

In new states that were formed by secession, such as the post-Yugoslav and post-Soviet states, language policy can be conditioned by powerful neighboring states. Russia’s demonstrated willingness to intervene in neighboring states such as Georgia on behalf of ethnic Russians has forced essentially all of the post-Soviet states to weigh the relative costs of provoking Russia by insisting on the official and educational use of their titular languages versus subordinating their nation-building efforts to the benefits of deeper integration within a Russian cultural (and possibly economic and political) order. Scholars have argued that Ukraine was for many years wary of provoking Russia by suppressing use of the Russian language, which might lead to accusations that it was also suppressing ethnic Russians, arguing that Russia has used the “ethnolinguistic card” to protects its political and ethnic interests in its near abroad. Estonia and Latvia, in contrast, sought to actively differentiate their countries from Russia by enforcing the use of Estonian. This has been a consciously antagonistic policy: “As a result of the second wave of Baltic language legislation, monolingual non-titulars were effectively contained by a combination of different laws, which introduced requirements of proficiency in the state language. This containment tended to go too far in some cases such as the controversial language requirements for private business and elected officials. In Estonia, in the name of national integration, the state language will also be imposed on the state-financed minority-language secondary schools, which have to start switching their language of instruction to the state language in 2007. In Latvia, the same process has to take place even earlier, in 2004.” Their entry into NATO in 2004 has rendered the threat of any potential Russian intervention moot, making it more feasible to institute these policies.

In Ukraine, the government sought to expand use of Ukrainian over Russian from the earliest days of the post-Soviet period as a means of asserting national identity. However, the Russian language occupied a dominant position in Ukrainian life for many years, despite official efforts to promote Ukrainian language. According to the 2001 census (a decade after independence), not only was Russian spoken by the vast majority of the population as either a first or second language, many citizens who identified as ethnic Ukrainians actually spoke Russian as their mother tongue. Other linguistic minorities were still more likely to have a command of Russian than of Ukrainian. Moreover, Russian as a first language was particularly dominant in urban areas and among the more highly educated. One study using data from before the Russian takeover of Crimea observed that “Russian tends to prevail in post-Soviet contexts where it is established as the main language of business, communication, and education if there are no policies in place to restrict its use and to actively promote the titular or other languages. Indeed, this is the argument generally brought forward, for example in Ukraine, in order to promote policies that mandate Ukrainian. But even when such restrictions exist, Russian still tends to be used in informal situations or in the business environment.” Since the 2014 hostilities with Russia and especially since the 2022 invasion, however, language preferences appear to have flipped. Residents in the areas not occupied by Russia are increasingly identifying with the Ukrainian language as a national statement, even if their mother tongue is Russian. Meanwhile, in Crimea, which was always predominantly Russian speaking, minority languages including Crimean Tatar have been suppressed. Clearly, it is impossible to disentangle political circumstances from ethnic and linguistic identification.

Language policy is an important issue in unrecognized states as well. For example, in both the Georgian breakaway territory of Abkhazia and the Moldovan breakaway territory of Transnistria, language laws were designed “with the aim of promoting new state identities, supporting nation-building projects, and furthering claims to statehood”—even when the governing bodies did not have the ability to actually implement, fund, or enforce them. In the case of Abkhazia, the main purpose has been to differentiate itself from Georgia. While there have been efforts to promote use of the Abkhaz language, in practical terms Russian has been by far the most widely spoken language and the state has lacked the capability to develop curriculum and train sufficient numbers of teachers in the Abkhaz language, so the main effects have been the solidification of Russian as the dominant language while also making the territory inhospitable for Georgian speakers.

Transnistria, in contrast, has focused its nation-building not on a rejection of Moldovan language in favor of Russian or by championing one particular ethnic group, but on a “civic, supra-ethnic understanding of nation.”1 Transnistrian language policy offers legal and educational equality for its three official languages of Moldovan, Russian, and Ukraine, and moreover requires that all residents learn at least one of those as a second language as well. In practice, Russian has been the most popular language of instruction and, in non-Russian-language schools, Russian has been the most popular second language as well, reaffirming its position as the territory’s dominant language.

Challenges of Economic Reconstruction

Economic factors are important to the success of post-conflict reconstruction. As noted above, promises of economic aid from external actors often accompany negotiated settlements. These will typically follow the rules of national or multilateral aid agencies or development banks, reflecting both the preferences of donors and the ability of the post-conflict society to meet conditionality and performance requirements. One type of official funding that is not relevant in contemporary post-conflict reconstruction is reparations from defeated enemies. Reparations have essentially disappeared from actual practice in the post-World War II world, although victims of aggression often demand them in negotiations. The closest thing to an exception is continued economic aid from former colonizers (e.g., French aid provision in Francophone Africa), but these remain at the discretion of the former colonizer. Otherwise, the only ways to get material or financial resources from an unsuccessful aggressor are to seize property within the country or for external powers to seize assets and transfer assets held outside the country (e.g., in foreign bank accounts or the assets of state-owned enterprises or individuals close to the leadership).

Despite the importance often assigned to economic aid in discussions of post-conflict reconstruction, it is also essential to bear in mind the crucial role of private money. Attractiveness to foreign investment goes a long way toward explaining differing post-conflict outcomes in Serbia and Croatia, for example. Access to foreign investment depends on several factors, including perceived risk of violence, quality of regulations and rule of law, and effective governance, in addition to standard concerns like quality and cost of labor or the availability of government guarantees. Unrecognized quasi-states (e.g., Abkhazia and South Ossetia) find it particularly difficult to attract FDI. Meanwhile, studies of post-conflict societies in Africa have shown that private remittances far outstrip aid and foreign investment. This is also true more generally for many lower and middle-income economies and especially post-conflict ones, including throughout the Balkan and Caucasus regions. That has been the case in Bosnia, for example, which saw inward FDI of $492 million in 2017 (2.8% of GDP) in contrast to $2.01 billion in remittances (11.5% of GDP). Post-conflict foreign investment often comes predominantly from diaspora populations, further heightening their role in reconstruction. 

Challenges for Unrecognized States

Within the international system, there is a wide range of entities that look like states in some respects, but that are not recognized as such by the international community. Referred to variously as “quasi-states,” “de facto states,” “para-states,” “states in all but name,” and “unrecognized states,” they operate in a legal limbo.  Some of these unrecognized states, such as the Turkish Republic of Northern Cyprus (established in 1974 and recognized only by Turkey) and Somaliland (established in 1991 and not recognized by any UN state), have considerable staying power. However, the existence of many such entities is precarious even when they have been internally effective and existed for decades, as seen in Nagorno-Karabakh, where the Republic of Artsakh (an Armenian enclave inside of the recognized borders of Azerbaijan) operated autonomously from 1991 until 2023, when Azerbaijani forces took control of its last remaining pieces of territory.

External recognition is important to states for several reasons. First, unrecognized states do not benefit from the territorial integrity norm that has mostly held since the end of World War II. They are under constant threat of attack from the “home states” (also known as “parent states”) whose jurisdiction over their territory is recognized by other states in the international system. When conflict between unrecognized and home states occurs, it is typically treated as an internal matter by bodies such as the United Nations. Unless an unrecognized state has an external patron willing to defend it or provide resources, it cannot depend on the intervention of international organizations to maintain its territorial integrity.

Unrecognized states often do maintain foreign relations. For example, Somaliland, which is not recognized by any UN states, has 16 overseas representative offices, including in the United States, China, and a variety of European, Middle Eastern, and African countries, and at least nine countries maintain representative offices or consulates in Somaliland. The Turkish Republic of North Cyprus (hereinafter, “Turkish Cyprus” or TRNC), similarly, is recognized only by Turkey, but has representative offices in multiple countries. Unrecognized states also often interact with the UN, OSCE, and other international agencies, either as part of a mediation process, maintenance of a ceasefire, certain functional cooperation, or in some cases as recipients of aid (e.g., Kosovo prior to its widespread recognition by the UN and other states). However, they remain heavily disadvantaged in terms of their access to resources and ability to affect global governance relative to recognized states.

Unrecognized states face what is referred to in the literature as the “economic cost of non-recognition.” They are typically ineligible for multilateral aid (except with permission of the home state government) and lack access to the global banking system. While some may control valuable resources such as oil or diamonds that can be traded on international markets, those without control of such resources must rely on a combination of remittances, trade (often in the form of smuggling), foreign direct investment, and various illegal activities. Due to the uncertainty associated with their status, FDI to unrecognized states is generally low. In general, remittances are the largest source of legal foreign exchange for unrecognized states, except where a powerful patron state is willing to fund them. In addition, the issue of illegal activities is an ongoing concern for unrecognized states, due to either to poor governance, the inability to access legal external markets, or both. In the words of the journalist Fred Kaplan, unrecognized states are often “conduits for trafficking in drugs, arms, and even people.”

Political conditions in unrecognized states are often worse than in the home state or external patrons. For example, Global Freedom ratings for 2023 show Crimea (at 4 on a 100-point scale) and Eastern Donbas (3) far below Ukraine (50) or even Russia (16). Similarly, Abkhazia (39) and South Ossetia (12) are rated far below Georgia (58), albeit above Russia, and Turkish Cyprus (76) is well above its patron Turkey (3), but below Cyprus.154 This is not universal, however, as seen in the example of Somaliland (44, compared to Somalia’s 8). As seen in the Cyprus and Abkhazia cases, unrecognized states can also outstrip their patrons. Nonetheless, the economic disadvantages of lack of recognition are essentially universal, with the only counterexample of an unrecognized state registering better economic conditions than its home state being Somaliland.

In short, “non-recognition locks unrecognized states out of a states-only club whose members enjoy benefits in terms of both security and economic integration.” This raises the question of how unrecognized states continue to exist, in some cases for multiple decades. The short answer is that essentially all long-term successful unrecognized states have a powerful external patron, which provides essential economic and military resources—and in some cases, even military forces to prevent reabsorption by the home state. For Taiwan, the external patron has been the United States. For the former Yugoslav states as well as Kosovo prior to their generalized recognition as states, it was the United States plus NATO and the EU. For South Ossetia, Abkhazia, and Transnistria, the patron has been Russia. For Turkish Cyprus, it has been Turkey. Virtually the only long-term unrecognized state without an identifiable external patron is Somaliland, which has benefited from Somalia’s status as a failed state. As one study concludes, “Support by a foreign patron is, in almost all cases, necessary for the persistence of unrecognized statehood. When there is no patron, or when the patron withdraws its support, military reconquest by the home state is likely.”

In many cases, external patrons share a border with unrecognized states. This facilitates provision of resources and movement of people (including workers and traders as well as soldiers and insurgents). Proximity in some cases allows for functional economic integration and even effective outsourcing of key services. For example, it has been argued that “far from being de facto independent, [Abkhazia and South Ossetia] have instead significantly outsourced (or have had outsourced for them) high levels of independence and administrative autonomy to Russia through the securitization of their borders by Russian peacekeepers, the use of the Russian rouble as an official currency (Abkhazia, South Ossetia), the outsourcing of governmental functions to Russia (South Ossetia), and the politics of recognition by Russia, … thereby rendering them ‘de facto Russian regions.’”

External patrons choose to support unrecognized states (as well as rebel and secessionist movements in general) for several reasons. Two in particular stand out: co-ethnic ties and international rivalries. Ethnic ties across legal borders have driven foreign support of unrecognized states in many cases, ranging from Turkey’s support of Turkish Cyprus to Serbia’s support of Republika Srpska in the Bosnian conflicts to Armenia’s support of the Republic of Artsakh to Russian support of Russian-speaking minorities in Ukraine and Georgia. International rivalries can also drive external patronage, regardless of ethnic, religious, or ideological proclivities of the unrecognized state, in some cases even at long distances. The involvement of great powers in conflicts can be sufficient to keep them going indefinitely, particularly if there are opposing great powers supporting each side.

Fates of Unrecognized States

While unrecognized states can persist indefinitely in some cases, their existence is fundamentally unstable. Thus, it is important to address the question of how unrecognized states evolve. There are four possible avenues to end unrecognized status:

  1. Integration into external patron state. To date, this has been the least likely outcome—as a 2006 article stated that “So far, there are no examples of successful inclusion into the external patron state.” Several unrecognized states have put this forward as a goal, including the Republika Sprska in Bosnia and South Ossetia in Georgia. However, as of this writing, there remain no good examples. While Russia recognizes South Ossetia as a sovereign state, it has chosen not to reabsorb it despite Ossetian entreaties. Arguably, pieces of Luhansk and Donetsk have been reabsorbed by Russia, but with Russia and Ukraine still at war at the time of this writing, it is hard to make a conclusive case.
  2. Full independence and recognition by the international community. There are a variety of such examples in recent history, driven in particular by post-WWII decolonization, the break-up of the Soviet Union, and the break-up of Yugoslavia. There are also some sui generis examples, like South Sudan. In general, successful transitions to full statehood have required one of two conditions. First is the consent of the home state, as seen in the post-Soviet states as well as post-WWII decolonization. In the absence of such consent, the actions of great powers, particularly the U.S. and to a lesser extent the EU, have been decisive. As Bridget Coggins writes, great powers’ “recognition carries the greatest weight and has the greatest potential influence on others. Typically early movers, when the Great Powers agree, their decision serves as a focal point that initiates a cascade of legitimacy throughout the system’s remaining members.”
  3. Reabsorption into the home state. Given the disadvantages associated with lack of international recognition, many unrecognized states are simply defeated by the home state, as in the cases of Katanga in the Republic of Congo (now the Democratic Republic of Congo), Biafra in Nigeria, and Tamil Eelam in Sri Lanka. This is particularly likely where there has been external patronage that ends for some reason.
  4. Inclusion into home state as a separate entity in a power-sharing arrangement, such as in the form of federal system or confederation. This is, for example, how Republika Srpska was incorporated back into Bosnia and has also been the basis of the proposed (but as yet-unfulfilled) Annan Plan to reunify Cyprus. Formal power-sharing has also been used in other ethnically or religiously divided societies such as Iraq and Lebanon even where there was no interlude of secession or unrecognized statehood for part of the country. While often seen as the most desirable and potentially most stable way to reintegrate an unrecognized state, negotiated federal solutions are typically driven by the international community or external great powers. Moreover, “pressure must be put not only on the local parties but also on the external patron state.” An external patron that is either weak or dependent on the support of the international community is most likely to concede to such pressure. 

External Recognition and Conquest

External recognition can, similarly, be a challenge for established states that seek to absorb a conquest. For example, Israel’s control and declarations of sovereignty over the West Bank, Gaza Strip, and Golan Heights have attracted considerable international criticism. While the history of occupation, establishment of the Palestinian Authority, and Israeli settlements is a complicated and fraught one that is beyond the scope of this paper, lack of international recognition has clearly hampered Israel’s ability to control those territories. Indeed, widespread recognition of the Palestinian Authority by other countries (including 138 UN members, nearly as many as the 165 that recognize Israel) has subjected Israeli policies to significant scrutiny and has allowed for large-scale provision of economic resources to the West Bank and Gaza. 

External recognition can be most important in times of stress. In late December 1975, Indonesian troops took over East Timor, a Portuguese colony that had declared its independence earlier that year. The international community reacted negatively, including with a General Assembly resolution and a unanimously-adopted Security Council resolution, both of which called on Indonesia to respect the territory’s right to self-determination. This disapproval was reaffirmed repeatedly between 1976 and 1982. Nonetheless, Indonesia incorporated East Timor as a domestic territory (albeit administered under martial law) until it allowed the UN to organize a referendum in 1999 that led to the establishment of the independent state of Timor Leste in 2002. Despite widespread disapproval, and occasionally condemnation, of Indonesia’s actions, actual repercussions were limited. International aid declined in 1977, but soon bounced back. At various points, U.S. military aid was curtailed, but overall aid remained substantial—for example, Indonesia remained the largest recipient of Japanese aid—and trade grew monotonically. Indeed, Indonesia was a linchpin of both U.S. and Japanese policy in Southeast Asia, and was also generally supported by its regional neighbors, including the Association of Southeast Asian Nations and Australia. It is hard to find evidence that Indonesia was very negatively affected either economically or politically for much of the period in which it controlled East Timor, but at crucial moments the lack of recognition damaged Indonesian interests—most notably in 1999, when the UN sponsored East Timor’s independence referendum and subsequently supported an Australian-led PKO in response to violence by paramilitaries and the Indonesian military.

As another example, the Soviet Union’s annexation of the Baltic states in 1940 was never recognized by the United States or other Western states. Nonetheless, there were few consequences either during the period of wartime alliance or during the Cold War, where Western non-recognition of the annexation was a minor irritant among the many larger issues between the USSR and NATO. However, the contested legality of the annexation did smooth the Baltic states’ reintegration as sovereign states in 1991, supporting the notion that external recognition becomes most important in times of stress.

New State Creation after Conflict

In recent decades, interstate and civil wars have given rise to a number of new states and quasi-states. These range from entities that are widely recognized by the international community (e.g., South Sudan, East Timor, Eritrea, and various components of the former Yugoslavia) to ones that are partially recognized (e.g., Kosovo) to “quasi-states” that are recognized by only a handful of states (e.g., South Ossetia and Abkhazia). 

Weak state capacity is a common feature of newly-created states and quasi-states, reflecting not only the difficulty of developing effective state functions but also the often-tenuous nature of post-conflict political settlements. Lack of recognition by major donor countries and international organizations exacerbates these challenges for unrecognized quasi-states, but even large-scale economic and technical support has not guaranteed successful outcomes in terms of public service provision, economic growth, protection or human rights, or state stability. Also, it should be noted that the purposes for which a new state or quasi-state is created—e.g., whether as a unilateral or mutually agreed buffer state between hostile states or as an ethnic enclave with undisputed borders—do not have systematic effects on the governability or even the external security of these new entities. In general, the best performing post-conflict new states are (a) ones that already had effective state governance within long-standing borders (e.g., former Yugoslav states like Croatia) and (b) ones that are widely recognized and receive sustained support from the international community. As for buffers, the best guarantee is multilateral involvement that can restrain both hostile parties. In cases of unilateral buffers—for example, by Israel in Golan or Russia in Abkhazia—absence of conflict depends on the unilateral restraint of the (more powerful) state that has established the buffer.

To illustrate some of the challenges of political development of new state entities created after interstate conflict, we focus here on the cases of Kosovo and South Ossetia.

Kosovo: Disputed State with Multilateral Support

Kosovo was a long-time territory of the Ottoman Empire until it was taken by Serbia in the Balkan Wars in 1912. Thereafter, it was a province of Serbia, which in 1918 joined the newly-formed Yugoslavia. Kosovo’s population has been predominantly Albanian and Muslim, unlike that of Serbia, which was predominantly Serb and Orthodox Christian.166 In the 1990s, as Yugoslavia fell apart, conflict arose in Kosovo between the Kosovo Liberation Army (KLA, which claimed to represent the Albanian Muslim Kosovars) and the Serbian government, whose leadership was dedicated to Serbian nationalism. An internationally-brokered ceasefire in 1998 was soon violated, leading to renewed violence between the KLA and the better-armed Serbian army, as well as a plethora of reported cases of Serbian military violence against civilians. Responding to concerns of Serbian government violence against Kosovar civilians, NATO undertook a forceful bombing campaign of Serbia proper in 1999 that led to Serbian military withdrawal from the territory and the creation of the UN Interim Administration Mission in Kosovo (UNMIK) supported by a NATO-led military force in which troops from Russia and a variety of other countries also participated. 

UNMIK sought to reconstitute Kosovo’s internal governance under new principles of democracy, human rights, property rights, and private enterprise. Crucially, however, it left open the question of statehood, which was strongly opposed by Serbia, as well as other interested parties including Russia. While this question complicated the UNMIK mission, UNMIK worked to build governance structures, parliamentary elections, a professional police force, and protection of minorities—in particular, for the Serb minority, many of whom still identified with Serbia. The post-conflict reconstruction of Kosovo was a complex undertaking that included multiple organizations and aid agencies, including the United Nations, the OSCE, the EU, and the U.S. Agency for International Development (USAID), among others.

The contradictions between the liberal democratic norms of UNMIK and local realities appeared in a variety of instances, including the creation of the Kosovo constitution. One key disagreement was between Kosovar legal experts and civil society groups that espoused Kosovo independence on the one hand and UNMIK, whose mandate did not include the establishment of an independent state. Despite lip service to the principle of bottom-up democratic constitution-building including a popular referendum, UNMIK’s concerns about the attempt to declare sovereignty in the constitution led it take a much more top-down approach in practice. As one observer writes, “The international statebuilders intervened extensively in Kosovo’s constitutional design and flouted bottom-up local agency.” However, they did take into account the concerns of the Kosovo community through various roundtables and working groups, with the final compromise reflecting both the interests of major political groups and the expectations of UNMIK for ensuring democracy, human rights, and minority rights.

In 2008, Kosovo formally declared independence. While it has not been recognized by Serbia or Russia, it has been recognized by roughly half of UN member-states as well as most EU and NATO members. It is not a member of the UN, for which Russian approval (or at least non-opposition) would be a prerequisite, but it is a member of a variety of international organizations including the International Monetary Fund, World Bank, European Bank for Reconstruction and Development, and Permanent Court of Arbitration, among others. It is also, like Serbia, an applicant for EU membership. In a February 27, 2023 agreement, Serbia promised not to oppose Kosovo’s membership in international organizations. However, a 2022 UN assessment still rings true in its conclusion that “Lack of agreement on the normalisation of relations between Pristina and Belgrade is hindering progress.”

Kosovo enjoys peace along and unfettered travel across its borders, including with Serbia. This stability has been maintained with the continued presence of KFOR (now primarily composed of NATO forces, with Russia having withdrawn in 2004), although its numbers have declined from around 50,000 at their peak to under 5,000 in 2023. Ethnic Serb-majority enclaves in northern Kosovo have remained a flashpoint between Kosovo and Serbia, despite constitutional protections and power-sharing provisions provided to Serbs and other minorities. As noted in a Congressional Research Service report, “Pristina has been unable to exert full authority in northern Kosovo, whereas Serbia has retained strong influence (albeit not full authority) there despite the withdrawal of its forces in 1999. Kosovo Serbs turned to Serbian-supported parallel structures for security, health care, education, and other services.”

Arguably, the Kosovo experience has been a considerable success, as there has not been a recurrence of large-scale violence either within or across borders. However, that stabilization was achieved following significant ethnic conflict; moreover, departures of ethnic minorities have further reduced the ethnic heterogeneity of the territory. Thus, domestic peace in Kosovo is arguably an example of successful partition, made possible by ethnic cleansing and the voluntary retreat of the Serbian population. In addition, continued external support has been essential to this success, in both security and economic terms.

Economically, Kosovo is one of the poorest countries in Europe, with a per capita GDP of USD 5,351 in 2022, according to the World Bank. It has been highly dependent on aid (albeit down from 8-10% of GDP in 2010-12 to around 5% in recent years) and remittances (estimated at 16-19% of GDP for 2019-21). It has borrowed from both the World Bank and EBRD. On a per capita basis, Kosovo has been the largest recipient of EU aid. Nonetheless, growth has been slow and economic opportunities limited, contributing to significant out-migration. Surveys of Kosovo’s economy cite challenges of governance and corruption, in addition to standard economic challenges of geography, human capital, and infrastructure. 

Access to EU, U.S., and multilateral funding, as well as the prospect of accession to the EU have been powerful motivators of cooperative behavior by both Serbia and Kosovo, while KFOR has helped to keep the peace and UN and OSCE missions have contributed to fair elections and state capacity building. Efforts at capacity building have had mixed results. For example, an ambitious EU program to promote rule of law (EULEX) has had limited effectiveness and appears in some ways to have established a parallel court system that deals with difficult political issues when the domestic system cannot. Whether Kosovo’s relative success is sustainable in the absence of such support appears questionable. As one study observes, “Although the statebuilding project in Kosovo has sought to build effective institutions, the local political elites, as they went on to take power, have used public assets for the interests of their parties and clans, and to reward businesses associated with them.” Another argues that the central importance of external aid and approval has stunted Kosovo’s political development, in particular the willingness of political actors to develop effective political and governing coalitions with domestic rivals, noting “the continuing fragility of the regional peace process where vertical relationships with internationals are more significant than horizontal relationships among local actors.”

Caucasus: Unrecognized Quasi-States

South Ossetia and Abkhazia are territories within the internationally-recognized borders of Georgia that have resisted control by Tbilisi with the support of Russia. While neither is a true ethnic enclave, ethnic Georgians are a minority in both.

South Ossetia and Abkhazia have sometimes been characterized as buffer states between Russia and Georgia that have been created and maintained via Russian actions. This stretches the definition of buffers, in that Russia proper has never been militarily or politically threatened by Georgia. Instead, although these unrecognized quasi-states were first created ostensibly as a way to protect ethnic Russians and Ossetians from persecution by the Georgian government, they have quickly become outposts of Russian military might, hosting Russian military bases and relying on Russian troops to protect their borders against Georgian forces.

South Ossetia’s separatist movement, which now controls the territory, has long called for reintegration with North Ossetia within Russia, whereas Abkhazian separatists had advocated for their own country. As of now, however, both are in similar positions as quasi-states that are recognized by few states besides each other and Russia. Moreover, their political systems and economies are deeply and increasingly intertwined with Russia and both territories host Russian troops are in bases, limiting their actual autonomy. The result has effectively been the shrinkage of Georgian-controlled territory, but without the benefits of a true buffer zone for it, since Russian troops are stationed just as close to Georgian troops as before and much closer to Tbilisi and other important cities.

That said, there is still some multilateral support for reducing conflict, even after the end of the original peacekeeping agreements. As of 2019, the unarmed civilian EU Monitoring Mission continues to monitor the 2008 ceasefire agreements; however, “although the EUMM’s mandate covers all of Georgia, local and Russian authorities do not permit it to operate in Abkhazia and South Ossetia.” Moreover, all of the parties to the ceasefire, including the U.S., EU, UN, and OSCE participate in the quarterly Geneva International Discussions and in the jointly-administered Incident Prevention and Response Mechanisms, which are meant to ensure transparency and build mutual confidence.

The borders of the two territories have been fluid over time. Although temporarily secured by multilateral forces and OSCE observers in the mid-2000s, the current demarcation line reflects further conflict between Georgian and South Ossetian forces and is unilaterally secured by Russian forces. While neither Georgia nor South Ossetia is ethnically homogeneous, “the current demarcation line between South Ossetia Georgia basically reflects the complex ethnic population pattern and follows a highly intricate course… Some Georgian settlements are virtually surrounded by South Ossetian territory, and vice versa. This also means that border is extremely difficult to defend.” That said, over time, the ethnic composition of South Ossetia, including border towns, has shifted with the departure of many ethnic Georgians, such that the border looks more like an ethnic partition than it had historically.

Both South Ossetia and Abkhazia are characterized by weak governance capabilities and economic dependency. South Ossetia offers an interesting case study in the adoption of new laws and constitution, as leaders of the separatist movement had long desired to reunite with North Ossetia as part of Russia rather than to exist as a separate sovereign state. For this reason, the leaders of the breakaway territory essentially adopted Russia’s constitution and laws wholesale. Weak rule of law has also led to large-scale corruption, which further erodes the legitimacy and effectiveness of local governance. As one 2011 study stated bluntly, “the Russian leadership’s attempts to establish effective control over South Ossetia’s authorities and prevent funds from being embezzled have not been successful so far.”

Economically and functionally, Abkhazia has been highly reliant on support from Russia and international NGOs such as the Red Cross and Doctors Without Borders. The South Ossetian economy benefits from its position as a route for legal and illegal trade between Georgia and Russia, but it too relies heavily on Russian aid and logistical support. Both territories also benefit from remittances from workers in Russia as well as Russian-supplied pensions for seniors who worked in Russia during the Soviet period. Reliance on Russian aid and pensions has limited the development of the South Ossetian economy: “It has been shown that as a result of large-scale assistance from Russia, a structurally weak hyperservice economy has formed, whose key industries depend on government demand and Russian investments.” In contrast, Georgia has been able to rely on the support of the EU and U.S. and the IMF, and has entered into free trade agreements with the EU and China, even as Russia has remained a major trading partner and source of remittances. The result is that South Ossetia and Abkhazia have experienced economic stagnation, corruption, and weak governance as a result of their autonomous status, even as Georgia has improved in all three dimensions.

The lack of international recognition and support has hurt South Ossetia and Abkhazia’s governance and economic development. As illustrated by the South Ossetian and Abkhazian cases, unrecognized quasi-states are characterized by weak statebuilding for several reasons. In addition to the after-effects of physical damage from conflict, they are excessively dependent on the economic support of a patron state. They also suffer from the “economic cost of non-recognition.” In South Ossetia and Abkhazia’s cases, this includes embargos by Georgia (their only direct neighbor besides Russia) and lack of access to resources from the EU, U.S., and UN. This stands in sharp contrast to the situations in more widely recognized new or reconstituted states like Kosovo or Bosnia. In addition, the legal limbo of unrecognized quasi-states discourages foreign investment, leaving remittances, aid, and trade with Russia as the dominant sources of foreign exchange. As one recent study concludes, “the lack of external legitimacy limits access to markets and creates difficulties for financial and trade transactions.”

Finally, it should be noted that the lack of an armed and capable international peacekeeping force essentially means that these unrecognized quasi-states are a kind of frozen conflict, making their borders and potentially even their existence inherently unstable. In the cases of South Ossetia and Abkhazia, the establishment of Russian bases effectively deters attempts by Georgia to reclaim territory. However, Georgia would not be in a position to deter Russian-supported aggression, since it is militarily weaker and is not a member of NATO or other military alliance. In other words, unilaterally-imposed buffers operate in only one direction, and so peace along the border is dependent on the restraint of the stronger power. A similar situation obtained in post-Soviet Ukraine. While the Budapest Memorandum included pledges by Russia, the U.S., and UK to respect Ukraine’s borders, Ukraine’s weakness relative to Russia and lack of alliance support allowed Russia to change the territorial status quo in 2014. This intervention was based on Russia’s unilateral interpretation that the removal of President Yanukovich constituted a Ukrainian abrogation of the Budapest Memorandum by Ukraine and thus justified Russian action to protect ethnic Russians in Ukraine. Russia’s 2022 invasion further demonstrates the point that deterrence is essential to make non-intervention pledges meaningful.