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date: 21 January 2021

War Terminationfree

  • Carmela LutmarCarmela LutmarSchool of Political Sciences, University of Haifa
  •  and Lesley TerrisLesley TerrisInterdisciplinary Center Herzliya


War termination is not a monocausal event but rather the product of a multitude of strategic, political, and psychological factors. Variables at different levels of analysis, such as power distributions, regime types, leadership and leadership changes, and psychological factors are all found to influence war termination processes. Recent studies have also explored how variables at different levels of analysis interact with one another to impact the onset and outcome of war termination, across different types of conflict (interstate and intrastate). Dynamic Bargaining models contribute to our understanding by perceiving war termination in terms of the parties’ ability to reach a mutually beneficial agreement, against a background of accumulating costs and under conditions of incomplete information.


An impressive body of research has developed in the field of international relations on interstate, intrastate, and transstate wars. In the past, much of this research focused on the causes and the consequences of war, with relatively little attention given to war termination. In the last two decades or so, however, the emphasis has shifted considerably with growing scholarly interest in war termination (Goemans, 2000a, 2000b), ceasefire agreements (Fortna, 2004), the duration of wars (Bennett & Stam, 1996), and the stability of peace (DeRouen et al., 2009). The shift is hardly surprising considering the numerous ongoing conflicts in the system, old conflicts that have come to be viewed as intractable, as well as an increasing number of, mainly intrastate, conflicts that have erupted in the international system over the past several decades. Finally, with the increase in the number and scope of nonstate actors involved in conflict, the study of war and war termination is more complex than ever.

This article offers an overview of some of the main research conducted on war termination, while highlighting new and promising avenues of research. The article opens with a discussion of war termination from the perspectives of the Balance of Power and Power Transition theories. The following two sections cover the impact on war termination of regime types and leadership changes, respectively. Next is a discussion of the conception of war termination as a bargaining problem. Finally, focusing on the psychology of leaders’ decision-making in conflict settings, the influences of past decisions on current policies are explored.

War termination entails the formal end of fighting, not necessarily the end of conflict. In other words, war termination is not, though it may lead to, resolution of the underlying issues in conflict between rivals. Fighting in the Korean War, for example, ended in July 1953 without resolution of the underlying issues (until this day). Within the realm of war termination, the literature also speaks to different types of war termination. A war may be terminated by one side gaining victory and the other side accepting its losing status (at least temporarily), such as that occurred in the First Gulf War in 1991, wherein the coalition forces achieved a decisive victory and liberated Kuwait from the Iraqi forces. Alternatively, war termination may be achieved through peaceful negotiations as in the case of the Good Friday Agreement, which ended the conflict in Northern Ireland. Negotiated settlements may achieve war termination at different levels, ranging from partial settlements such as ceasefires to full peace treaties. Regardless of the type of termination (military or negotiated), the termination of war may be long-term or, in cases of war recurrence, short-term.

Balance of Power, Power Transition, and War Termination

Power distribution theories analyze war largely from the perspective of unitary state actors and assume that sovereign states act rationally to advance their security and power in an anarchic international system characterized by the absence of a global authority. The realists’ primary emphasis on distribution of power is prominent in balance of power theories (e.g., Claude, 1962; Kaplan, 1957; Morgenthau, 1973), which generally posit that the maintenance of an equilibrium of power in the system ensures a stable system. When that equilibrium is upset, when one state or alliance of states threatens to secure a hegemonic position, it is then that war is most likely to be initiated.

The Power Transition Theory (PTT) takes a more dynamic view on power distribution than the balance of power theory (Organski, 1958; Organski & Kugler, 1980). Briefly put, the PTT describes a hierarchical international system in which the distribution of power is uneven and concentrated in the hands of a few. The dominant nation, which controls the largest portion of resources within the system, sets the rules of the game, or status quo, for the entire system. These rules of the game, determine the political, economic, diplomatic, and military interactions in the international system. The dominant country establishes this order because it benefits the dominant power and its allies in the form of wealth, security, and prestige. Other states that do not benefit from the status quo but who are too weak to challenge it may strive to increase their power and attempt to change the rules of the game. Thus, PTT anticipates war when a newly rising country approaches power parity with the dominant state and is also dissatisfied with the international status quo. Such a dissatisfied rising power, known as a challenger, will demand changes that will likely be resisted by the dominant state. The combination of power parity between challenger and dominant state combined with the challenger’s negative evaluation of the status quo provides the necessary condition for war. The war is fought for control of the “rules of the game” of the international system, with the expectation that victory by the challenger will be followed by a restructuring of diplomatic, economic, and military relations between nations. Because PTT does not measure power exclusively in terms of military power (but rather considers economic growth rate) and also takes into consideration a country’s satisfaction with the workings, or status quo, of the international system, it is not considered a purely realist theory (Lemke, 1997), but rather a neorealist or neoliberalist theory. Originally a systemic theory focusing on prevalence of a hegemon, scholars have expanded power transition research to the regional and dyadic levels as well (e.g., De Soysa, Oneal, & Park, 1997; Houweling & Siccama, 1988; Kim, 1991; Lemke & Reed, 1996).

Fervent scholarly discourse on PTT has been reignited over the past decade or so in light of China’s remarkable development path, triggering debate over the extent and components of China’s rise, as well as over the extent of its satisfaction or dissatisfaction with the status quo. The result is a plethora of theoretical works and predictions regarding the possible onset of global instability or even a great power war (e.g., Allison, 2015; Chan, 2004; Ikenberry & Liff, 2014; Jeffery, 2009; Lim, 2015; Ross & Zhu, 2008; Tammen et al., 2000, chapter 7). The debate is featured in a 2015 Special Issue of International Area Studies Review, which brings together path-breaking works on power transition theory and providing a more solid understanding of China’s rise and its implications for the international system (e.g., Kim & Gates, 2015; Lee, 2015; Tonnesson, 2015). Shifting focus from interstate wars to civil wars, Toft (2007) demonstrates the applicability of the Power Transition Theory to contemporary intrastate conflicts by examining if “shifts in the relative proportions of a state’s ethnic group affects the likelihood that conflicts between groups will escalate to civil war” (p. 243). This issue is of particular importance in the 21st century as civil wars, extreme draughts, and other humanitarian crisis events continue to drive mass movements of people across borders and regions, in many cases upsetting fragile demographic equilibria.

The conditions for war termination in both the Balance of Power theory and in the PTT are implied in the theories themselves. The Balance of Power reasoning suggests that once war has begun, conflict behavior will end when the challenger is counter-balanced and a new balance of power is achieved. PTT leaves room for a wider range of possibilities for war termination. In addition to the option of the dominant state militarily defeating the rising challenger in a war initiated before the rising challenger has surpassed it in power, or the challenger defeating the declining dominant state in a war initiated after the rising challenger has surpassed it, the theory leaves room for a third option, negotiations. For, if satisfaction of the challenger with the rules set by the dominant power is a factor, then negotiations over the rules of the game might lead to peaceful settlement of the conflict. Such negotiations could take place as a preventive measure, before any onset of hostilities, or once war has begun, to end it peacefully.

According to some scholars once war has begun, power parity between the rivals is necessary for successful peaceful war termination. This line of reasoning speaks to Zartman’s ripeness model (2001), wherein it is only when the rivals perceive themselves to be in a Mutual Hurting Stalemate (MHS) that they will agree to engage in negotiations to end their conflict. A mutual hurting stalemate will occur when each side realizes that it does not possess sufficient military power to achieve unilateral victory over the opponent, and that continuation of the conflict entails accumulation of hurting costs. A mutual hurting stalemate may occur between the rivals without external intervention, or it may be prompted by a third party (Zartman, 2001). A prime example of the latter case is given in the United States’ decision in 1973 to delay the military airlift to Israel and again, towards the end of the war, to prevent Israel from destroying Egypt’s encircled Third Army. In this manner, the United States was setting the stage for ending the war through peaceful negotiations: By preventing each side from gaining a decisive victory, the United States was hoping to offer each side in a settlement something more than it would get by continuing the conflict (Terris, 2017).

In addition to the perception of an MHS by both sides, Zartman’s ripeness model includes another factor, a perception of a Way Out (WO) as a necessary condition for the onset of negotiations to end conflict. The perception of a WO suggests that ripe moments exist when leaders know they cannot achieve their objectives through violence, and they are prepared to search for better and less costly outcomes. Such an opportunity might emerge from interparty factors, such as the advent of a new leadership on one of the sides, from intraparty factors such as in the relevant terms on offer from the adversary, or from extrasystem factors, such as pressure from third parties (Mitchell, 2000). Incentives offered by a third party might also help establish a WO. Although these two conditions, perception of a MHS and a WO, according to Zartman, do not guarantee successful war termination, they are necessary conditions for the onset of negotiations. In addition, Zartman (2001) claims, a ripe moment is “optimally associated with an impending, past or recently avoided catastrophe.” The condition of a catastrophe provides parties with a deadline and an incentive to take action sooner rather than later. Zartman also points out that a factor that is likely to derail or block negotiation even if all the other conditions stand is the presence of “spoilers” intent on destructing any kind of negotiations that may lead to compromise.

Extensive research focusing on the peaceful settlement of wars has enriched the war termination literature in recent years, with interesting findings on the impact of power distributions within these processes. The underlying logic of the rational perspective is that a player with a decisive power advantage over its rival will be less willing to cooperate in a negotiation process to end war, under the belief that it has the ability to gain more by force. The message in the quantitative literature on the effect of capability ratios on conflict behavior and conflict management, however, is somewhat mixed. Dixon (1993), Bercovitch and Regan (2004), and Greig (2001) do not find robust and consistent effect of power ratios on peaceful war termination processes. Yet, several mediation studies find support for the theory that mediation is more likely to occur when rivals are equal in power (Greig, 2005; Terris, 2017). Focusing on crises (as opposed to war), Quinn et al. (2006, p. 443) find that “while crises are more likely to occur among asymmetric parties, symmetric crises are more likely to be mediated” (italics in original source). Conversely, Barringer (1972, p. 114) finds that although rivals tend to enter into war when their military forces are relatively equal, once war has begun, de-escalation is associated with a shift in the military balance against the side suffering greater losses.1 Within the context of civil wars and focusing on the effectiveness of mediation as a peaceful war terminating tool, Clayton (2013) and Clayton and Gleditsch (2014) show that strong insurgents capable of credibly threatening the government are more likely to reach agreements.

Democratic Regimes and War Termination

While traditionally scholars of war termination have analyzed the topic largely from the perspective of unitary state actors, research from a liberal approach has focused on the role of a state’s domestic characteristics. Within this context, states’ regime type (level of democracy), trade relations with other members in the international system, and membership in international organizations form the so-called the Kantian tripod for Peace.

Perhaps no topic in the study of conflict has received more attention by scholars of international relations in the past several decades than the “democratic peace.” What began in the early 1980s with the observation that political democracies rarely, if ever, fight wars against one another on the one hand, but are not less war prone than nondemocracies on the other hand, produced a massive body of literature, spawning thousands of books and articles. Efforts to explain the democratic peace finding have focused mainly on cultural/normative and/or structural institutional factors (e.g., Bremer, 1993; Hermann & Kegley, 1996; Maoz & Russett, 1993). Maoz and Russett’s article (1993) is particularly notable in this respect as, unlike many others, it seeks to explain not only why democracies do not fight one another, but also why they are not less war prone than other regime types. The democratic peace carries important implications for war termination. Situations in which two democratic states face each other in a conflict of interest will resolve their difference peacefully. With their normative democratic values of peaceful conflict resolution and institutional structures that require the mobilization of both general public opinion and of a variety of institutions prior to military action, democratic dyads will have the tools and the breadth of time needed to resolve their conflict peacefully. Additionally, each side can rely on the other side to behave similarly. Conflicts between a democracy and a nondemocracy, however, are driven by the lack of shared peaceful conflict resolution norms and structural constraints on the mobilization and escalation process of the latter. Thus the democratic state finds itself in a no-choice situation and finds ways to become more flexible in abiding by democratic norms and circumvent the due political process. Thus, the literature suggests and is supported by empirical evidence that joint democracy increases the likelihood of war termination by peaceful means, either through direct negotiations or mediation by a third party (e.g., Brecher & Wilkenfeld, 2000; Dixon, 1993, 1994). Conflicts between nondemocratic systems are, by the same token, likely to escalate because both leaderships operate under relatively few structural constraints. The failure of initial efforts to find a peaceful solution may result in a rapid flare-up of the conflict into a violent level. Conflicts between democracies and nondemocracies and between two nondemocratic states are more likely to escalate into war and end militarily.

Approaching the relationship between regime type and war initiation and termination from a different perspective, Bueno de Mesquita et al. (2003) suggest that the decision to enter or terminate war largely depends on leaders’ political survival assessments. The political survival theory refers to two sets of people—the Selectorate (S), which denotes the group of people that participates in the election of the leader, and the Winning Coalition (W) which is a subset of the Selectorate, and which constitutes the set of people whose support the leader depends on for political survival. Based on these two dimensions, one can distinguish between types of regime type and the degree to which states are democratic. Whereas democratic states typically have a large (W) and an even larger (S), less democratic states may also have a relatively large (S), yet they will typically have a small (W), as the group of people keeping the leader in power is smaller than in more democratic regimes. Unlike democratic leaders’ reliance on citizens’ votes to keep them in power, autocratic leaders need only provide enough private goods to the elites on whose support the leader relies. Engagement in war, even in the case of defeat, need not interfere with this logic. Whereas autocrats need only satisfy a small circle of supporters even in the case of defeat, democratic leaders must be careful not to engage in actions that may lead to their defeat by foreign adversaries because failing in those adventures will likely cost them the next elections (Bueno de Mesquita & Siverson, 1995).

The above implies that democratic leaders will engage in wars only if they think the likelihood of winning is very high, and they will be more likely to prevail. This is the result of having to pay higher costs for failed policies (Bueno de Mesquita & Siverson, 1995). According to this theory, rather than democratic norms or institutions accounting for democracies’ behavior, the reason democracies will be less likely to escalate conflicts to war are political survival considerations (Dixon, 1993, 1994). Additional implications of the theory are that democracies are more likely to win the wars they fight because they are highly selective in deciding whether to negotiate or fight. For this reason, democracies are also inclined to reach peaceful settlements when disputes arise with other democracies, to experience fewer deaths in wars they initiate (as a result of efficient mobilization of resources), and to fight shorter wars than autocracies will. Furthermore, democratic leaders try harder to win wars, and so they make relatively unattractive targets, and they initiate wars only if they expect to win (Bueno de Mesquita et al., 2003). Autocratic leaders can afford to take more policy risks than their counterparts, because once they face autocrats, they need only a slight advantage to initiate a war. Once they face democratic leaders, they will need overwhelming odds because the latter will fight much harder (Reiter & Stam, 2002).

Leader Changes and War Termination

Recent research has sparked new interest in questions regarding the incentives of leaders to terminate or continue war (e.g., Chiozza & Goemans, 2003, 2004, 2011; Downs & Rocke, 1994; Goemans, 2000a, 2000b). As part of this effort numerous works have focused on when and why regime and leadership changes might impact the probability for peaceful war termination (Bennett, 1997; Croco, 2015; Stanley, 2009a, 2009b; Stanley & Sawyer, 2009). In broad terms, authors who put forward a “new leader” theory, suggest that leadership changes increase the bargaining range between nations allowing leaders to pull away from belligerent policies (Lieberfeld, 1999; Mitchell, 2000; Stedman, 1991). Several reasons might account for this. Firstly, internal political changes expose strategies and ways out of a situation which might have been overlooked or ignored by the previous leadership (Greig, 2001; Stedman, 1991). Secondly, even cases in which the current leadership supports negotiations, a change in leadership might be needed to change course and pursue negotiations (Lieberfeld, 1999; Mitchell, 2000; Stedman, 1991). Thirdly, new leaders are not necessarily committed to the policies of their predecessors or held accountable to them. Therefore, they will find it easier—and politically less costly—to pull away from failed conflict policies (Mitchell, 2000, pp. 89–90). In fact, the very advent of a new leader will often produce, or result from, an expectation for a policy shift, thus creating an environment in which new strategies are easier to pursue. Finally, adversaries are less likely to harbor distrust against new leaders than against their predecessors, making it easier to engage in a negotiation process. Thus, periods of leadership change may signal the potential for the development of a peaceful conflict resolution process.2 Bercovitch and Lutmar (2010) find statistical support for this argument when tested against a dataset covering 221 interstate conflicts that took place in the 1945–2000 period. They find that conflicts in which one or both of the participating countries experienced leadership changes are likely to be conducive to the initiation of negotiations and mediation, and that this relationship is stronger in democracies than in nondemocracies. Examining the effect of foreign imposed regime change as a war termination strategy, Lo, Hashimoto, and Reiter (2008) find that imposing a friendly leader in the defeated state will result in much longer periods of peace between the opponents.

In shifting focus to intrastate, as opposed to interstate wars, the leadership change–war termination relationship is theorized to be less straightforward and more complex (Lutmar & Terris, 2016). Because civil wars often concur with a revolutionary struggle, frequently spawn multiple groups with competing interests, and often involve individuals who place principles before interests, these conflicts tend to be more multifaceted, drawn out, and intractable than interstate wars, consequently entailing particularly high negotiation costs and risks (Lutmar & Terris, 2016). Instead of clearly defined and legitimate representatives of governments that partake in interstate negotiations, leaders of these groups are not always officially recognized, are often reluctant to engage in any formal negotiations and are motivated themselves by complex and often contradicting interests. New leaders may not only be reluctant to break away from such fluid circumstances but might also seek to bolster support of the group members and strengthen cohesion among them by emphasizing intransigent positions both vis-à-vis the government and vis-à-vis competing groups, rather than flexibility. When these groups constitute rejectionist movements, splinter groups, or spoilers, intent on derailing any progress made in negotiations, new leaders are even more unlikely to shift to positions that allow for compromise. Although rendering negotiations a particularly difficult endeavor such actors cannot be ignored.3 Therefore, leadership changes under conditions of multiplicity of competing groups and subgroups may lead to greater inflexibility, at least in the short term (Lutmar & Terris, 2016). Another leader-specific factor that may impinge on a peaceful impact of leadership change is that in many intrastate conflict situations, rebel groups leaders profit personally from the ongoing conflict, especially when natural resources are exploited to fuel the dispute and personally benefit the rebel leaders (Collier, 2000; Collier & Hoeffler, 2004). This implies that neither the current nor the succeeding leader would have a strong incentive to reach a settlement. While governments involved in interstate conflict may benefit from conflict as well, such benefits are typically in the realm of public support (such as in a rally-around-the-flag effect), do not last long, and are not likely to survive leadership shifts.

The above suggests that when it comes to leadership changes among sides engaged in civil war, these complexities will lend to a relationship that is less straightforward and pronounced between leadership change and conflict resolution than that which appears to exist in interstate conflicts, particularly when the leadership change is on the side of a rebel group. Even in cases where the new leaders identify an interest in ending the conflict peacefully, new rebel leaders will find it more difficult and politically risky to change course than new government leaders. One explanation for this is that new rebel leaders often lack the necessary legitimacy base, political apparatus, and resources that new government leaderships—both in democratic and nondemocratic regimes—possess and that are needed to implement policy shifts without destabilizing their power base. Thus, the complexities involved in civil war will lead to different, and more sophisticated, causal mechanisms between leadership change and negotiations processes.

Indeed, recent empirical studies on civil wars based in different large-n datasets has produced some insightful results. For example, Lutmar and Terris (2016) find that the impact of leadership change on the probability for the signing of a peace agreement in the short term depends on the side in which the leader shift took place. Whereas leader change on the government side prompts the signing of peace agreements within six months of the leader change, rebel leader changes do not prompt peace agreements at all in the short term. Tiernay (2015) finds that rebel leadership change matters, though only when the change is prompted by the killing or capturing of the former rebel leader. With respect to leader change on the government side, the study finds that the leader of a state that presided over the beginning of the conflict is significantly more likely to bring the conflict to an end than a replacement leader. Prorok (2016) finds that leaders in general (regardless of the side) who bear responsibility for involvement in the war tend to continue to fight rather than make concessions, implying that new leaders might be more susceptible to ending war peacefully.

War Termination as a Bargaining Problem

Bargaining models postulate that rational actors have a set of tools at their disposal, war being one of them, when they try to achieve their goals (Reiter, 2003). Recognizing that war is very costly, rivaling parties will do everything in their power to avoid a military confrontation. The rational approach suggests that actors may fail to reach an agreement preventing war or ending war, due to (1) poor information or incentives to misrepresent information, (2) commitment problems, and (3) issue indivisibilities (Fearon, 1995).

Once in war, the adversaries incur costs (in military capability, economic capacity, domestic support, international backing, and battle deaths and casualties) which accumulate as long as the conflict continues. This implies that a bargain is more desirable than the continuation of war, even if the bargain requires concessions, and that an agreement earlier on in the conflict has more value for a disputant than an agreement at a later stage in the conflict (Reiter, 2003, 2009; Rubinstein, 1982; Terris, 2017; Terris & Maoz, 2005). Their problem is that the rivals may not know what that agreement is—because of incomplete information—or they cannot afford to propose one—due to commitment problems.

According to the bargaining model of war, fighting represents the sides’ failure not only to reach a mutually beneficial bargain, but also failure to agree on the side that would make concessions and the nature of those concessions. In this respect, fighting allows sides to gain knowledge of the opponent’s strengths and weaknesses, helping them eventually move towards a war-terminating settlement bargain that is more attractive than the prospect of continued fighting (Goemans, 2000b; Slantchev, 2003, 2004). The seminal works on war termination by Goemans (2000a) posit that rivals assess their success probability in achieving war aims based on past interactions with the enemy and that this learning process is crucial in determining how they evaluate the prospects of reaching a settlement. Relying on statistical analysis as well as on in-depth analysis of the behavior of Germany, Britain, France, and Russia during World War I, Goemanns also demonstrates that the incentives that drive leaders to continue or end war vary depending on the type of government they represent, as domestic politics affect how different regimes perceive and change their war aims.

The development of rational models that also account for the impact of so-called soft factors such as rivals’ mutual mistrust and credibility concerns, has provided greater insight into the bargaining demands and outcomes of actors both in bilateral and mediated negotiation settings (Kydd, 2003, 2005; Maoz & Terris, 2006; Terris, 2017).

Although originally formulated within the context of interstate wars, the adoption of bargaining models by civil war researchers has contributed considerably to the understanding of civil war and its termination. Such models have allowed scholars to reach beyond the perception of civil wars as driven by irrational feelings of hatred and to conceive of adversaries in civil war as rational, utility-maximizing actors who engage in armed conflicts because of bargaining failures and who stop fighting once the sources of those failures are addressed. For example, focusing on information asymmetries, Cunningham (2006) looks at the role of “veto players” who may serve as spoilers and continue fighting even when other groups agree to a peace settlement. He finds that the larger the number of veto players involved in a conflict, the more difficult it is to end the civil war. Walter (1997) focuses on the difficulty of rebel groups to disarm themselves as a commitment problem in bargaining, noting that nonstate actors fear that surrendering will render them vulnerable and defenseless should the government defect from the agreement.

Research suggests that information and commitment problems in bargaining may be mitigated through several means. For example, with access to all of the parties involved in the conflict, mediators may help decrease information asymmetries (Kydd, 2003; Maoz & Terris, 2006; Rauchhaus, 2006; Terris, 2017). Guarantees provided by third parties to ensure compliance by the opponent and the presence of peacekeeping forces might serve to alleviate commitment problems (Fortna, 2008). Sound power-sharing measures can also serve as a means to deal with commitment issues (Hartzell & Hoddie, 2007).

Psychological Influences on War Termination: Inaction Inertia and Sunk Costs

In addition to the impact of strategic, diplomatic, economic, and political circumstances, war termination processes are also influenced by the belief systems, emotions, and psychological biases of the individuals who formulate foreign policy. Until recently, traditional study of war and war termination left little room for these sets of factors. Indeed, the leading research agendas discussed in this article, such as power distribution theories and the liberal approach, give little weight to the role of individual political leaders. In recent years, however, numerous researchers have turned to mechanisms and concepts that were originally developed in the field of psychology to explain policy outcomes. This approach is aptly reflected in Levy’s observation that “ variations in the beliefs, psychological processes, and personalities of the individual decisions makers explain a significant amount of the variation in foreign policy behavior of states in the international system . . .” (Levy, 2003, p. 255). The considerable impact of the thriving subfield of political psychology can be seen a tribute to the merits of this approach.

Originating at the individual level of analysis, psychological variables interact with causal variables at other levels of analysis in explaining the decisions and behavior of states in war and peace. Researchers adopting the psychological perspective argue that in order to fully understand the behavior of states it is also necessary to focus on the individuals who make the key decisions, as foreign policy decisions reflect the aggregation of their preferences, beliefs, attitudes, and judgments.

The psychological approach suggests that failures to end wars may have psychological origins. “Motivated biases,” in particular, rooted in individuals’ psychological needs and fears, may impair rational decision-making and lead to biased judgments and suboptimal choices (Janis & Mann, 1977). The literature refers to a host of psychological effects that may impact leaders’ decisions such as loss aversion, framing, anchoring, reactive devaluation, and optimistic overconfidence (e.g., Levy, 2003; McDermott, 2004; Mintz & Redd, 2003).

Since conflict and conflict termination are not single-shot events, but rather processes that evolve over time, an important aspect of understanding decisions to end war is the impact of past decisions on current ones. One psychological approach which focuses on the impact of past decisions and which has recently made its way into the international negotiations literature is the concept of inaction inertia. Developed and extensively researched in the field of social psychology, the term “inaction inertia” was first introduced by Tykocinski, Pittman, and Tuttle (1995) to describe the reluctance of individuals who had missed an attractive action opportunity to take a subsequent action opportunity in the same domain. Inaction inertia occurs when the current opportunity is substantially inferior to the one forgone, although objectively it still has positive value in an absolute sense.4 A history of a missed opportunity renders decision-makers susceptible to regret, which they can circumvent, at least temporarily, by quickly turning down subsequent action opportunities. Such a predicament holds particular weight in international negotiation settings where forgoing an attractive action opportunity exposes the decision-maker not only to self-recrimination and anticipated regret, but also to public scrutiny and criticism. By quickly dismissing the current action opportunity, the decision-maker is able to terminate this unpleasant thinking process and avoid the pangs of regret, albeit at the cost of missing yet another opportunity. Evidence for inaction inertia in the context of international negotiations was obtained in the analysis of the negotiations over the release of the Israeli captured soldier Gilad Shalit (2006–2011), as well as in two scenario-based surveys (Terris & Tykocinski, 2016). Also significant for war termination analysis was the finding that male participants in the experiments were more prone to inaction inertia behavior patterns than females (Terris & Tykocinski, 2016). The observed gender differences could be linked to the public nature of the international relations context, as some research suggests that men are more status-conscious and therefore, possibly, more sensitive to public criticism than women (Tannen, 1994). In addition, these gender effects are consistent with the Women and Peace hypothesis which portrays women as showing higher propensity for compromise and lower propensity to use violence, compared to men (Caprioli & Boyer, 2001; Conover & Sapiro, 1993; Fite, Genest, & Wilcox, 1990; Hudson et al., 2012; Togeby, 1994; Wilcox et al., 1996). The concept of inaction inertia can enrich the understanding of failures and deadlocks in international negotiations aimed at ending war.

Although distinct, inaction inertia bears some similarities to another psychological effect, which also focuses on the impact of past decisions on subsequent choices: sunk costs.5 In psychology, the sunk costs effect refers to the tendency of individuals to continue committing resources (in money, time, or effort) to an endeavor—which endures even when the initial investment fails to produce the expected outcomes (Arkes & Blumer, 1985; Thaler, 1980). Various explanations have been offered to account for sunk costs effects including both private and public attempts at self-justification (Staw, 1981; Teger, 1979), misapplication of the norm against waste (Arkes & Ayton, 1999; Arkes & Blumer, 1985), and information-processing heuristics (Whyte, 1986). In international relations studies, the sunk cost effect has been used to explain the tendency of states to continue investing in foreign policies despite their negative outcomes and has been implicated as a potential cause of continued conflict (see, e.g., Goldgeier & Tetlock, 2001; Renshon, 2015). Sunk costs have been empirically linked to a host of wars and military interventions, international negotiations, and the length of commitment to conflicts such as the United States in Vietnam and Israel in Lebanon (Maoz, 2006, pp. 173–230; Meerts, 2005; Staw & Ross, 1989; Taliaferro, 1998; Von Hippel, 1996).

Thus, whereas inaction inertia might prevent decision makers from acting upon optimal policies (such as a good settlement offer that promises to end war), sunk costs motivate them to continue pursuing suboptimal action policies (such as a costly war). Like in other psychological biases, the identification of these effects by the decision maker may in itself serve as a first step towards its termination. In both sunk costs and inaction inertia, decoupling the past from the present may help decision makers exert themselves from the decision pattern. In this respect third party mediators may play a meaningful role, both by (1) identifying deadlocks induced by leaders’ focus on past decisions (be it a missed opportunity or a decision to pursue a bad policy) and (2) by using this insight to break the deadlock. Possible interventions may include redirecting attention to future benefits rather than past missed or misused opportunities, and redefining the situation in a way that decouples the past from the present. The conditions under which these two biases are most likely to occur and the question of whether inaction inertia or sunk costs may trigger peace under certain circumstances require further theorizing and empirical investigation.


An understanding of war termination is a critical aspect of war and is center to an understanding of the phenomenon of war as a whole. Research has made great advances over the past couple decades towards a better understanding of the conditions and processes involved in ending wars, as scholars have shifted focus to concentrate on the question of war termination from diverse perspectives. Power relations, regime types, internal political processes such as leadership shifts, and decision processes are all factors that are found to impact war termination, sometimes differently when dealing with intrastate wars as opposed to the more traditional interstate wars. To address the ever-changing playing field of conflict, promising avenues of research have emerged that expand traditional theoretical boundaries to include new concepts and approaches, and that address important issues associated with contemporary war and warfare at all levels of analysis. Additionally, existing datasets have been expanded and new datasets compiled to include war termination-relevant variables in both interstate and intrastate wars and which serve as the basis for a burgeoning body of research that will surely continue to uncover the mechanisms at play when leaders consider the timing of war termination, the manner of that ending, and the possible consequences.


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  • 1. See Vasquez (2009, pp. 206–208) for a discussion.

  • 2. Changes in leadership may not always lead to changes in policy. New leaders may simply assume the positions of those they have replaced, especially if the old leaders are established and well regarded. It is not also necessarily the case that a change in leadership and a subsequent review of options, goals, and policies, will result in a more conciliatory pattern of behavior (Mitchell, 2000, p. 90). That said, given that conflict is already taking place, conciliatory options that did not exist (or were not perceived as existing) beforehand are more likely to surface or become exposed with a “change of the guards.”

  • 3. For example, the collapse of the Arusha Accords in 1994 and the ensuing genocide exemplify the potential catastrophic consequences of failing to include such extremists in negotiations or otherwise neutralize them (Clapham, 1998).

  • 4. For reviews, see Anderson (2003); Tykocinski and Pittman (2004); and Van Putten et al. (2014).

  • 5. For a comparative review on inaction inertia and sunk costs see Tykocinski and Ortmann (2011).