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Subscriber: null; date: 17 September 2019

What Do We Know About Civil War Duration? A Bargaining Perspective

Summary and Keywords

Civil wars vary greatly in duration—some end within months; others last for decades. What explains this variation? Civil wars drag on when no combatant can win a military victory and the various actors involved are unable, or unwilling, to reach a compromise agreement that resolves the war. Military victory does happen in civil war, but it is rare, so understanding why civil wars last as long as they do requires examining the barriers to negotiated settlement.

Wars last longer when the parties involved perceive the war as less costly relative to peace and when the combatants are overly optimistic about how they will do in the war. Even when key decision-makers see the war as costly and are realistic about their chances of prevailing, negotiated settlements prove elusive if the parties cannot accept a division of the issues at stake or if the government or rebels are unable to trust the commitments the other side makes in a negotiation. Additionally, bargaining is more complicated when there are more combatants that must accept the terms of any agreement, and conflicts with more combatants last much longer than those with fewer.

Many factors affect the bargaining environment, and these barriers to bargaining can explain why civil wars are on average quite long. International actions can alleviate some of the barriers and help combatants reach comprehensive settlements, as happened in the conflicts in Mozambique, El Salvador, Guatemala. In particular, peacekeeping and mediation strategies are effective at resolving wars sooner. International action in general is more effective, however, when the parties involved are interested in peace but need some help overcoming commitment or informational problems. These actions are much less successful when that interest is lacking.

The current civil war in Syria has many of the factors identified as prolonging wars. It is an extremely fractionalized conflict, and many external actors are involved. Syria has a large majority population that has been historically excluded from political power and economically marginalized, and a minority government that has been dominant. These factors make reaching a comprehensive settlement very challenging and mean the war is likely to be very long-lasting.

Keywords: empirical international relations theory, civil war, conflict, conflict duration, conflict termination, military, peace process


Many civil wars last for decades. A peace process currently ongoing in Colombia has the potential to end a 52-year long civil war in that country. Wars that began during the Cold War continue in Somalia, Ethiopia, and Afghanistan. Yet other civil wars end much more quickly. The civil wars in the former Yugoslavia, while very destructive, ended in less than five years. The Biafran War in Nigeria lasted less than four. What explains this wide variation?

Put simply, civil wars last longer because they do not end sooner. The Biafran War ended when Nigerian armed forces were able to capture all the Biafran territory and the rebellion was defeated. The wars in the former Yugoslavia ended when a negotiated settlement was reached amid heavy international pressure and backing. Other wars, however, continue because no one actor is powerful enough to defeat the others and the parties involved are unable, or unwilling, to reach a political settlement that ends the fighting.

As such, the topics of civil war duration and termination are inextricably linked. Understanding the factors determining how long civil wars last requires examining those that influence whether civil wars end in military victory or negotiated settlement. Scholars have made significant theoretical and empirical progress toward understanding the conditions under which wars are likely to end and how conflict management efforts can make them more amenable to settlement. Even so, there is still a large degree of variation in when and how civil conflicts end that we cannot explain.

This article examines the current state of theoretical and empirical work on civil war duration and termination. It uses the bargaining framework to discuss the major factors that affect how long civil wars last, dividing the discussion into a focus on internal dynamics and the external dimensions of the conflict. In additional, it discusses strategies that have been identified as contributing to the resolution of the conflict, such as peacekeeping and mediation. The article provides a brief discussion of the civil war in Syria, demonstrating that that conflict has several dynamics driving a long duration and many barriers to resolution. It concludes by discussing areas where further research on the determinants of duration and termination is needed.

Before proceeding to this discussion, the article briefly examines issues related to measuring the duration of civil war, which is inherently related to our ability to study it. The measurement issues are more challenging than they might appear.

How Long Do Civil Wars Last?

Scholars studying the duration of civil wars typically do cross-national statistical studies using some event-history (or hazard) model, the Cox proportional hazards model being the most common approach.1 These statistical techniques were developed in medical research to examine how long patients lived after certain treatments (such as surgery). In the civil war context, scholars examine how variables influence how long civil wars last before they end.

Identifying how long patients in a medical study live is straightforward; measuring how long civil wars last is not. Of the many issues that account for this, several are prominent. First, civil wars often do not have an easily definable start date, since they do not begin with a formal declaration of war, and there is often a considerable amount of time between the first statement of an incompatibility and the outbreak of violence. Second, by the same token, wars often lack a definitive end, when one side is decisively defeated or a negotiated settlement leads to the full end of violence. Instead, the violence often declines to a point where it eventually peters out, which may or may not align with a political settlement. Third, disputes between states and nonstate actors often see rises and declines in the rate of violence, and there can be substantial periods during which there is no direct fighting. In these intermittent conflicts, it can be difficult to determine whether there is one long war or several shorter ones being fought between the same combatants.

Another important issue relates to whether and how to lump together the different rebel groups fighting within the same country. In Ethiopia, for example, the government has fought conflicts with Somali separatists and groups in the Oromo region, as well as with other groups that are fighting for control of the central government. The governments of India and Myanmar have both experienced conflicts with rebels representing ethnic groups based in different territories at the same time. Should these conflicts be lumped together or treated separately? This decision has significant effects on the measurement of civil war duration.

This article generally adopts a definition of duration in which civil war begins when there is an organized opposition, with a stated incompatibility with the government, and violence has crossed some threshold; it continues as long as the violence does not drop below this threshold for two years or more; and it ends when the violence drops below this threshold. The focus is on the duration of specific conflicts, by which is meant violent disputes between governments and rebel groups fought over the same set of issues. The wars between the Ethiopian government and Somali separatists, Oromo groups, and groups fighting for control of the central government are thus treated as separate civil wars, although each war can potentially involve multiple rebel groups fighting over the same territory.

Adopting this general definition, it is possible to identify some descriptive statistics for how long civil wars usually last. Two important trends stand out—the average civil war is long, much longer than the average interstate war, but there is a great deal of variation around that average. Among 288 civil wars begun between 1945 and 2003, the average length was just over five years, but the median was two years. Roughly one-third of civil wars lasted less than one year; roughly one-third lasted between one and five years; and roughly a third lasted more than five years. Among these long-lasting wars, 34 lasted between five and ten years, 29 between ten and twenty years, and 19 civil wars continued for more than two decades.2 There is a lot of variation in the duration of civil wars. What explains it?

Bargaining and Fighting

In one of the early scholarly works on the duration of civil war, Hironaka (2005) argued that civil wars have gotten longer over time because of the proliferation of weak states in the aftermath of decolonization. Normative shifts in the organizing principles of the international system mean that weak states can now persist, whereas in the past they would have been taken over (Jackson & Rosberg, 1982). However, these weak states frequently find themselves in wars they cannot win, and so the wars last a long time. Many studies have confirmed that civil wars last longer in states that are weaker (generally measured by GDP per capita).

However, though state weakness can explain why governments are unable to defeat rebels militarily, it cannot explain why these wars cannot be resolved through a negotiated settlement. To understand the factors driving these wars to drag on, many scholars draw on the bargaining approach to war. Building on Wittman (1979) and Blainey (1977), Fearon (1995) presented the bargaining approach most succinctly, which was then extended by many others, including Wagner (2000), Filson and Werner (2002), Smith and Stam (2004), and Slantchev (2003). The bargaining approach proceeds from the insight that conflict is costly, and that the actors involved therefore have incentives to find ways short of fighting to resolve disputes. Scholars have used the logic of the bargaining model to examine the conditions under which civil wars are, and are not, amenable to resolution, and have examined the implications of these arguments in empirical analyses of civil war. A number of characteristics have been examined, but these can generally be divided into internal characteristics of the conflict and the civil war state, and external influences on the dynamics of the war.

The Internal Dimension

The basic intuition of bargaining explanations of the duration of civil war is that civil wars last longer when parties are unable or unwilling to reach compromise settlements that all can agree to. A large literature has examined characteristics of conflicts that influence negotiation. Conflicts are more amenable to negotiation when the decision-makers perceive the conflict as costly, can accurately assess the relative balance of power between the different combatants, perceive that the issues under dispute are divisible, and are able to overcome problems related to credibly committing to some division. A large range of factors affect each of these bargaining dynamics.

The costs of civil war are very visible. People are killed, injured, and driven from their homes either internally or as refugees. Public-health infrastructure is destroyed, and the incidence of diseases increases. Normal economic activity is disrupted, leading to slower or negative economic growth. These objective costs are not sufficient for compromise settlement to be possible, however; instead, the actors involved have to perceive the conflict as costly.

Economic approaches to civil war, particularly those focused on the role of so-called lootable resources, argue that, in some cases, civil war is profitable for the actors involved (Collier, Hoeffler, & Sonderbom, 2004). Groups like the Revolutionary United Front in Sierra Leone, the Union for the Total Independence of Angola, and the Revolutionary Armed Forces of Colombia are seen more as criminal enterprises that are extracting resources than groups fighting for political change. As long as they are able to exploit these resources, they have little incentive to end the war, and the conflicts drag on.

While these economic explanations can help explain leader incentives to continue the war, they still have a fundamental challenge to explain duration from the bargaining framework. If conflict is costly overall, even if it is profitable for individual actors, ending conflict should provide sufficient spoils to make everyone better off, and compromise should be possible. The empirical evidence for the role of lootable resources is mixed, and it is not clear to what degree these resources are a barrier to bargaining in these wars.

Beyond the economic costs of war, other scholars have argued that nonmaterial costs and benefits can affect civil war duration. In particular, Horowitz (2009) argues that combatants in religious disputes often see nonmaterial gains from continuing to fight costly conflicts. In a related argument, Toft (2006) argues that actors in religious wars have longer time horizons, and thus will place more weight on the future benefits of conflict. Taken together, these arguments could mean that wars fought over religion last longer than other types of wars. There is some initial empirical evidence for this proposition (Svensson, 2007), and it is an important one to explore further because a considerably larger share of civil wars are currently fought over religion than in the earlier post–World War II period.

All the approaches just mentioned focus on when the actors involved view the conflict as costly. However, these actors do not just focus on the costs of conflict, but they compare them to the potential benefits (or costs) of peace. Reaching and implementing a settlement may also be costly for leaders in certain contexts. Prorok (2016) argues that both state and rebel leaders who are seen as responsible for fighting costly civil wars face punishment in the postwar period. For this reason, they may continue to fight costly wars in which there is little prospect of victory in a bid to “gamble for resurrection.”

Leaders’ perceptions of the costliness of war, then, can affect whether negotiated settlement is possible in these wars. The costs of war are just one factor that affect whether leaders see conflict as potentially more profitable than peace. The other is how well leaders think that they are likely to do in the conflict. If leaders are overly optimistic about their chances of prevailing in the war, they will continue fighting costly conflicts.

The role of “information” has received substantial attention as an explanation for the outbreak and duration of interstate war. It is likely, however, that actors in civil wars have greater difficulty in the early stages of wars assessing who is likely to win than in wars between states. Interstate wars are fought between standing armies, and there is generally a lot of information available on the size, composition, and budget for these militaries. Typically, then, leaders of states have at least some assessment of how powerful they are relative to other states. In civil wars, by contrast, rebel groups typically begin in an uncertain environment, and it can be difficult for both state and rebel leaders to know how much local support the rebels will be able to mobilize and whether and to what degree external states will come to rebels’ or the government’s aid. As such, negotiations in the early stages of civil wars are unlikely to succeed, because the actors involved have difficulty knowing how well they will do in the war and thus what kinds of demands they should make and concessions they should offer.

While informational approaches can help explain why negotiated settlements are rarely reached in the early phases of civil wars, they are not good explanations of why some of them last so much longer than others. One of the key insights of the dynamic bargaining models developed by Wagner (2000), Slantchev (2003), and others is that fighting reveals information, allowing actors involved to update their beliefs about the likelihood they will win. As civil wars drag on for years, it generally becomes obvious that neither side is likely to win without some dramatic change. There are dynamics of conflict that can shift the balance of power—in multiparty wars, in particular, as groups either leave or join the war this balance shifts (Cunningham, 2011)—but, these wars typically reach a point where it is clear that they will continue to be costly and not end soon. Yet, in many cases, these wars continue for years or decades beyond this point.

Why, if state and rebel leaders perceive that they are in a “mutually hurting stalemate” (Zartman, 1989) do they not settle civil wars but instead continue fighting? Two main sets of explanations emerge from the bargaining literature. First, civil wars can drag on if the actors involved perceive the issues under dispute as indivisible. Toft (2006) argues that issue indivisibility is an important factor in leading civil wars to drag on. Hassner (2003) and Goddard (2006) argue that in disputes over “sacred spaces,” such as Jerusalem and Kashmir, the disputants cannot contemplate a division of the territory. In these cases, then, the actors see fighting as the only way to achieve their goals, and costly conflicts can continue even if the actors involved see little prospect of victory.

Even if parties can see a potential division of the issues under conflict, for peace to be possible they have to agree to abide by whatever compromise is reached. In an influential body of work, Walter (1997, 2002) has argued that an inability to make credible commitments is the primary barrier to negotiated settlement in civil wars, and commitment problems can help explain why wars within states last so much longer, on average, than wars between them. In particular, Walter argues that civil wars are prone to commitment problems because rebels do not trust that when they start to disarm the government will not take advantage of their weakness to re-start the war. The government’s commitment problems may be exacerbated if government leaders have held office for a long time as they have established policy reputations and rebels are hesitant to believe they will change course (Uzonyi & Wells, 2016)3 or if the government has a history of discriminating against ethnic groups (Wucherpfennig, Metternich, Cederman, & Gleditsch, 2012). Rebels can also have difficulty making credible commitments, since they make unrealistic demands to try to signal that they are stronger than they are (Thomas, Reed, & Wolford, 2016). These credibility problems faced by governments and rebels can cause wars to drag on when settlement should be possible.

These are actor-focused explanations of the ability to make credible commitments, but the characteristics of the civil war state can also affect the ability to reach credible agreements. There is some evidence that civil wars in ethnically polarized states last longer (Montalvo & Reynal-Querol, 2010). Fearon (2004) argues that a subset of civil wars that he refers to as “sons of the soil” conflicts are particularly long-lasting. In these wars, a minority ethnic group faces in-migration from a majority population. These wars are not amenable to resolution because the majority population cannot credibly commit to limit migration in the future, regardless of its current position. Another societal dynamic that can make reaching credible agreements challenging is when a minority government rules over a majority population. In those circumstances, it can be difficult for the majority population to commit to not taking advantage of the minority after a political transition and for the minority government to commit to actual political openness.

The costliness of war relative to peace, the informational environment, the perceived divisibility of issues, and the ability to make credible commitments are the main factors identified as influencing whether negotiation is possible in civil wars. There is at least one additional characteristic of conflicts that has a significant influence on how long they last.4 In general, each of those main factors is examined in a situation in which the state is battling one rebel group. Many theoretical approaches that draw on the bargaining model examine bargaining between two actors—a state and a rebel group.

However, civil wars frequently involve more than one rebel group, as can be seen in the cases of Afghanistan, Colombia, Iraq, Myanmar, and Somalia. When there are more groups that have an ability to block settlement and to unilaterally continue the war, civil wars last much longer (Cunningham, 2006, 2011). The longer duration results from a more complicated bargaining environment as different groups bring different positions to the bargaining tables, combatants face greater challenges to accurately assessing the balance of power, all combatants have incentives to hold out to be the last signer and get the best deal, and challenges in creating and maintaining alliances among actors with different preferences make it difficult to overcome these problems.

Conceptualizing conflict as a bargaining situation, in which conflicts continue until one side wins or until all the key actors can see and commit to a negotiated settlement that gives them some, but not all, of what they want, provides key insights into why some civil wars are short and some are very long. All of the discussion to this point has focused on the internal dynamics of the conflict and civil war state in this environment. However, it is well established that civil wars often have external causes and effects (Gleditsch, 2007), and these transnational dimensions can have a substantial influence on the dynamics of wars.

The External Dimension

External actors play a large role in the dynamics of civil war. Some actions—such as providing financial or military support up to directly intervening in the war—are designed to influence the dynamics or outcome of the war, while others—such as mediation and peacekeeping—are designed to manage the conflict. In general, it makes sense to examine the various roles that external actors play in terms of how they affect the ability and willingness of the parties involved to bargain their way out of the war.

While civil wars involve rebel groups targeting violence against their government to try to achieve political change, rebels often base themselves in other countries. Doing so allows them greater protection from the government they are fighting because the governments of civil war states often cannot project power within their borders, let alone into another state. Additionally, states may face greater international condemnation for attacking in another state’s territory, even if rebel groups are based there. For these reasons, rebel groups, such as the Lord’s Resistance Army, the Union for the Total Independence of Angola, the Khmer Rouge, and the Palestine Liberation Organization have all been based in other countries. Empirical research has shown that civil wars in which the rebels are based in other countries last considerably longer than those in which they are not (Salehyan, 2007).

Beyond allowing rebels to establish a base in their territory, external states often provide support to governments and rebels. During the Cold War, much of this support came from the United States and the Soviet Union as they sought to bolster governments favorable to them and undermine governments on the other side of the ideological divide. This led to cases such as Mozambique and Angola, where much of the fighting was fueled by external support. In the aftermath of the Cold War, external support of civil wars remains common, although it has shifted in that governments are much more likely to get support than rebel groups (Cunningham, Gleditsch, & Salehyan, 2016). The effect of external support on conflict dynamics has generated a huge literature and, in general, the main finding is that external support makes conflicts last longer (Balch-Lindsay & Enterline, 2000; Regan, 2002).

From a bargaining standpoint external support can prolong conflict for several reasons. Providing extra resources to the parties to pay for the conflict decreases the costliness of conflict and thus the incentives to end it. In addition, rebel groups that rely on external support have less need to mobilize civilian support in their home country (Weinstein, 2007). However, decreased domestic support may mean that rebels anticipate doing less well in competitive elections following a compromise settlement, and so see less of a benefit to peace. Finally, the level of external support to governments and rebels is often variable, rather than constant, and shifts over time can lead to changes in the balance of power, which can generate commitment problems in bargaining (Sawyer, Cunningham, & Reed, 2015).

At the extreme, external states do not just directly support one side; they become directly militarily involved in the conflict. The 1998–2002 civil war in the Democratic Republic of the Congo (DRC) was often referred to as “Africa’s First World War” because it involved the armies of at least a half dozen states fighting against or alongside the Congolese rebel groups who were battling the government. In some cases, states intervene directly into civil wars to support domestic actors, but in others (as in the Congo), they also do so to pursue their own agendas, such as territorial control or the exploitation of resources. When external states intervening in civil wars have preferences that are different from the domestic combatants, they present an additional set of actors that can block an end to the conflict and further complicate bargaining, making these wars last much longer (Cunningham, 2010).

When external states allow rebel groups to base themselves in their territory, provide financial or military support to governments or the rebels, or intervene militarily into civil wars, it complicates the typical bargaining environment between governments and rebels. In general, the large literature on the external dimension to civil war has shown that all these external influences on civil war lead them to be longer. This suggests that a significant cause of prolonged civil war duration is external involvement. But beyond the external efforts to shape the outcomes of civil wars, the overall picture of international involvement in civil war is brighter.

In the nearly three decades since the end of the Cold War, the international community has put considerable effort into resolving civil wars. These efforts range from mediating and facilitating to sending observer and peacekeeping missions to providing economic and technical assistance in the postconflict phase. The effects of these actions have generated a large literature and, in general, this literature suggests that different international actions can help facilitate negotiated ends to civil wars, therefore causing them to end sooner than they would in the absence of this action.

One of the most prominent roles that international actors play in civil wars is mediation, whereby prominent individuals or teams seek to help the combatants reach an agreement. Prominent mediators have included the former Tanzanian president Julius Nyerere and the former South African president Nelson Mandela in the Burundian civil war, and former U.S. senator George Mitchell in the conflict in Northern Ireland. There are many cases of failed mediation, but researchers have shown that mediators typically become involved in the hardest conflicts. Mediators can help bring about a resolution to war by facilitating the flow of information between parties, offering material support to make a settlement more attractive, and threatening a withdrawal of material support or sanctions if no agreement is reached. Once the nonrandom assignment of mediators is dealt with, there is considerable evidence that mediation makes civil war negotiations more likely to succeed (Beber, 2012; Gartner & Bercovitch, 2006).

Another prominent role that international actors play is in providing peacekeepers. The UN currently has over 100,000 peacekeepers deployed around the world, with missions in several conflict-torn countries, including the Central African Republic, Mali, Haiti, the Democratic Republic of Congo, and South Sudan. Media reports often focus on the failures and abuses of civilians, which occur too frequently with peacekeeping, but a large body of empirical research has demonstrated that ceasefire agreements last longer when they are accompanied by the deployment of a peacekeeping mission (Fortna, 2008) and that when there are more peacekeeping troops deployed, the occurrence of both civilian deaths and battle-related fatalities declines (Hultman, Kathman, & Shannon, 2013, 2014). Peacekeepers can bring about peace directly by being positioned between combatants, reducing their ability to target one another and raising the potential costs of conflict. They can also contribute to resolution by helping parties to overcome commitment problems in the implementation phase of the agreement by monitoring compliance with such elements of the agreement as demobilization (Walter, 1997, 2002).

Peacekeeping and mediation have received the most attention in the literature, but research has shown that other international actions, such as human rights reporting (Burgoon, Ruggeri, Schudel, & Manikkalingam, 2015) and sanctions (Escribá-Folch, 2010) may lead to shorter wars as well. Not all international attention is necessarily productive, however; Narang (2015) has shown that humanitarian aid can lead to longer civil wars.

Many international efforts, then, can be seen as affecting civil war duration by helping these wars end sooner than they would if they were left to their own devices. Several long-running wars have ended following high-profile internationally led peace efforts, including wars in El Salvador, Guatemala, and Mozambique. The effectiveness of some of these efforts has led some to argue that the international community is “winning the war on war” (Goldstein, 2011) and that the decline in the occurrence of civil war is in large part due to concerted international effort. Yet not all of these efforts are successful, and there is considerable evidence suggesting that international actions are likely to be successful when the combatants are interested in peace but need some help to overcome the barriers to reaching it, but much less likely to be successful when the will is not there. As Doyle and Sambanis (2006) put it, the United Nations is good at “building peace” but bad at “making war.”

Shocks, Windows of Opportunity, and Bargaining

Many of the internal and external factors that affect whether and to what degree negotiated agreements are likely in civil war and thus how long these wars last, particularly the domestic attributes of the rebel groups, the government, and country within which they operate, are quite static, in that they do not change much over the course of the conflict. However, there are instances in which shocks of various types quickly shift the conflict dynamics and may provide an opening in which negotiated agreement is possible.

One prominent example of a shock was the end of the Cold War. As noted, during the Cold War the United States and Soviet Union provided support to governments and rebels they saw as on their side of the global ideological divide. In several cases, this meant that both the government and the rebels were receiving significant external support, which fueled long-running conflicts. When the Cold War ended, the Soviet Union and its allies stopped providing this support, and U.S. support began to be driven by other priorities. This decline created a window of opportunity in which to resolve some of the wars that were fueled by Cold War dynamics, such as the wars in Mozambique, Angola, El Salvador, and Guatemala.

Another type of shock that can open up a window for negotiations is the death of a leader. It is leaders who make the decisions about whether or not to negotiate on behalf of their groups, and in some cases, these leaders may refuse to negotiate even when it should be clear that victory for their side will prove elusive and that the conflict is costly. In Angola, for example, UNITA (the National Union for the Total Independence of Angola), led by Jonas Savimbi, fought the government into 2002 when it was generally clear that the group was losing both militarily and politically and had no prospects of winning the conflict. In February 2002, Savimbi was killed, and UNITA entered into serious negotiations with the government quickly thereafter. These negotiations generated a peace agreement that ended the conflict. Tiernay (2015) shows that the death of a rebel leader generally greatly increases the likelihood that a civil war will end.

Finally, a shock can result from an unexpected event that shifts the conflict dynamics. From 1975 to 2005 there was an insurgency waged by the Free Aceh Movement (GAM) against the government of Indonesia, which fought for a separate and independent Aceh. In 2004, the Indian Ocean tsunami had a devastating effect in Aceh, killing over 160,000 people on the island alone. The tsunami increased international attention to Aceh, including the conflict there, allowed international actors to link reconstruction funds to the peace process and was a major factor contributing to the signing of a peace agreement in August 2005 that ended the war. However, the tsunami alone cannot fully explain the successful resolution of the Aceh conflict. Sri Lanka was also devastated by the tsunami but the conflict between the Sri Lankan military and the rebel Liberation Tigers of Tamil Elam continued unabated. Rather, the specific characteristics of GAM meant that the tsunami led to a window of opportunity for resolving the war (Beardsley & McQuinn, 2009).

Fighting and Bargaining in Syria

The current civil war in Syria, which began in 2011, is ongoing. The Syrian conflict has been incredibly destructive, resulting in hundreds of thousands of casualties and the near complete destruction of the Syrian economy. Millions of refugees have fled the country and massive camps have been established in Turkey, Jordan, and Lebanon, posing a threat to regional security. The spike in refugees has led to an influx of migrants seeking to go to Europe, provoking a migrant crisis there. And, as generally happens in civil wars, the number of people who are internally displaced within Syria dwarfs the massive refugee population.

The Syrian civil war started following protests that occurred in Syria as part of the so-called Arab Spring, beginning in 2011. Whereas protests in Tunisia and Egypt had successfully led to the overthrow of authoritarian governments, the government of Bashar al-Assad in Damascus responded to protests in Syria with massive repression. This led to significant defections from the Syrian army, the formation of the Free Syrian Army, and the beginnings of the civil war.

The war in Syria has continued for years despite high-profile efforts led by the United Nations and regional organizations to promote a political settlement. The Syrian conflict exhibits many of the dynamics driving long civil wars described here. Two features of the Syrian civil war that have received the most attention are the high levels of external involvement and the degree of fractionalization among the rebels, both of which are associated with long conflicts. In addition, the nature of the Syrian society makes the achievement of a lasting political settlement very unlikely.

Many civil wars have external causes and influences; however, the degree of external involvement in the Syrian civil war is extreme. Different external patrons, from states such as Saudi Arabia and Qatar to rich individuals in the Persian Gulf states, funnel money to various rebel organizations. The Syrian government also has external backers. Iran has clear interests in supporting a Shia-dominated government in Damascus and Iranian forces have been directly involved in the conflict. The Lebanese rebel group Hizbollah has also fought on behalf of the Assad regime. Since 2015, Russia has provided military support to the Asaad regime, particularly in the form of air support. The United States, meanwhile, has not been involved in Syria to a large degree, but it has provided some support to rebels battling against both Assad and the rebel Islamic State.

The external dimension of the Syrian conflict presents a major barrier to settlement. The ready availability of funding to the various actors means that they have little incentive to work together or to seek civilian support inside Syria. Some of the external actors have their own clear agendas in the conflict—Iran, for example, is likely to be highly opposed to any resolution that does not result in Shia dominance of the government. In this way, these external actors represent additional players who have preferences over the outcome of the conflict and the ability to continue to fuel the war, reducing the prospects for a negotiated settlement. Although the Russian intervention has given the government the upper hand, it is unlikely that even with strong Russian air support the Syrian military will be able to fully defeat all the rebels, thus the war is likely to continue. The United States, meanwhile, has equivocated in its support for the rebels, and these unclear signals could potentially make resolving the war more difficult by leading the government and rebels to have differing expectations of the likelihood of U.S. support. These differing expectations could make it more difficult for the parties to agree on the likely future course of the conflict and thus to identify what a compromise political settlement should look like.

The internal dimension of the Syrian conflict presents an equal challenge to arriving at a peaceful resolution of the conflict. The Syrian war has a very large number of rebel groups. In general, the armed groups can be seen as allied into four main sides—the government and its allies, including foreign states and Hizbollah; the “moderate,” more secular opposition; Islamist groups (including the Islamic State and the Al Qaeda–affiliated al-Nusra group); and Kurdish groups. Within each, however, there is a proliferation of different groups. International actors have made efforts to promote unity, particularly among the moderate opposition, and to strengthen actors that might be able to bargain on behalf of these sides, but to little avail. While not all of these actors are “veto players” (Cunningham, 2006) in the sense of being able to continue the war unilaterally if all the other actors agreed, some of them are, and in general the proliferation of groups means that it will be extremely hard to reach a bargain that the key actors prefer to continued conflict.

The extreme degree of fractionalization and external involvement in the Syrian conflict has received much attention as the reasons that the conflict is so deadly and intractable, and rightly so, since these are important drivers. One element that has received less attention but is also important is the nature of the Syrian society. The Assad regime rules with significant support from the Alawi, a Shi’a minority group within Syria, and it protects the economic and political position of the Alawi. The majority of Syria’s population, meanwhile, is Sunni, and the country has a sizable Kurdish population. The combination of a minority group that is politically and economically dominant and a majority population that has historically been excluded creates commitment problems that can make resolving this war very challenging. The majority Sunni population will have difficulty committing to protect Alawi interests in the event of a transition to democracy, as the Sunni would likely take power in a majority-rule system. The Alawi government, meanwhile, has difficulty committing to any political transition because of its fears of majority rule. These problems mean that, even if the opposition were to overcome fractionalization and the external role in the conflict diminished, reaching a lasting political settlement in Syria will be challenging.

The current civil war in Syria, then, contains many of the key elements that complicate efforts to bargain compromise settlements and lead to wars of long duration. International efforts to resolve the war are likely to continue to fail, and the war will drag on for years, despite the incredibly high costs generated by the war to Syria, the region around it, and to important actors throughout the world.


The dual observations that civil wars are long on average and that there is huge variation around that average in how long specific wars last has led to both academic and practical interest in understanding the factors that drive long-running wars and what external actors can do to resolve them sooner. This literature has identified a large range of factors, both internal to the civil war state and external, that affect how long these wars last. In general, this work represents significant theoretical and empirical progress and our understanding of civil war duration and termination has significantly advanced. There are still areas, however, where further scholarship could improve our understanding. Three are highlighted here.

First, research on civil war duration and termination would benefit from a greater focus on the internal dynamics within both governments and rebel groups and how these dynamics influence how these actors interact with each other. The quantitative literature on civil war has made great strides in recent years through the effort to “disaggregate” the study of civil war to focus more specifically on actors, events, and locations. New data have, for example, allowed for examining how the strength of rebel groups relative to governments (Cunningham et al., 2009), the geographical locations in which the conflicts take place (Buhaug, Gates, & Lujala, 2009), and the specific dynamics of state-rebel group battles influence the duration and termination of conflict. Despite these advances, governments and rebel groups are still generally treated as unitary actors, and there is important theoretical and empirical work to be done in examining how the internal dynamics of these actors matter.5

Second, our understanding of civil war duration and termination could be enhanced by greater focus on other societal actors beyond rebel groups. Governments and rebel groups are the primary actors making decisions about whether or not to continue wars, and these actors have, appropriately, been the focus of the vast majority of theoretical and empirical work on this topic. Yet a range of other types of actors in society, including militias, political parties, religious groups, other civil society organizations and local nongovernmental organizations, can influence the dynamics of war and the prospects for peace.6

Finally, while the literature on international efforts to resolve civil wars has shown that such actions as peacekeeping and mediation can be very effective, it also generally reveals that these types of actions work when the parties already have an interest in peace but need help overcoming barriers to bargaining. The literature provides fewer answers about what can be done constructively in conflicts in which there is no political will for a compromise settlement, as appears to be the case in Syria now. Greater research on what international actors can do to make the parties more open to compromise, which would then set the stage for actions like mediation and peacekeeping to be helpful, would both further our academic understanding of the duration of these wars and potentially help facilitate a speedier end to destructive conflicts.


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                                                                                                                  (1.) A good overview of event history models is Box-Steffensmeier and Jones (2004).

                                                                                                                  (2.) These descriptive statistics all come from Cunningham (2011).

                                                                                                                  (3.) Although Thyne (2012) argues that powerful and stable leaders are associated with shorter conflicts.

                                                                                                                  (4.) There is also evidence that the strategies used by conflict actors influences duration. Findley and Young (2015) find that terrorism is associated with longer civil wars. Wood and Kathman (2014) show that negotiated settlement is most likely in wars with moderate levels of civilian victimization. Balcells and Kalyvas (2014) find that irregular wars last longer than conventional wars.

                                                                                                                  (5.) Cunningham (2014) provides an important look at how divisions within governments and self-determination groups influence how they bargain with each other, which has implications for the duration and termination of civil war but does not examine that topic directly.

                                                                                                                  (6.) Some of these types of actors are beginning to receive more attention. Carey et al. (2013) have new data on pro-government militias, and these data have been used to examine their influence on different conflict processes. Nilsson (2012) has examined the role of civil society actors in peace processes.