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date: 21 September 2017

Territory and Contentious Issues

Summary and Keywords

Territorial issues have been prominent causes of armed conflict and war in the modern era. This observation has led to a rapidly growing body of academic literature on the sources, management, and consequences of such issues. Although territory has gotten most of the scholarly attention, this literature has its roots in research on contentious issues that began in the 1960s. Academic research on contentious issues began with studies on issue areas in foreign policy analysis, focusing on such questions as how the foreign policy process differs from more traditional domestic policy processes. This line of research struggled to find mainstream acceptance until scholars began adopting a more substantive conception of issues, focusing on the nature of the values at stake. General patterns of foreign policy conflict and cooperation have been found to differ substantially across different issues. Importantly, territorial issues are the most frequent and most dangerous issues in armed conflict and war, leading scholars to focus much of their issue-related research on the dynamics of territorial contention.

Research on territory has stemmed from the main elements of issues theory that were developed earlier: issue salience, or the importance of the issue under contention; issue context, or recent interactions over the same issue; and institutional context, or the extent to which other actors and institutions are able to influence contention over this type of issue. Armed conflict is much more likely when the issue at stake is more salient, particularly when this salience involves intangible dimensions such as the presence of a state’s ethnic kin in the claimed territory. Greater issue salience also increases the likelihood of peaceful negotiations and nonbinding conflict management techniques like mediation. A recent history of armed conflict or failed negotiations over an issue increases the likelihood of armed conflict, bilateral negotiations, and nonbinding management. The normative and institutional context also appears to affect the likelihood of conflict and peaceful management over issues, although more remains to be done in this area.

The issues literature is beginning to make important strides beyond this initial work on territorial claim management. Scholars are beginning to geocode data on international borders, raising important potential benefits for the study of territory and perhaps other issues. International legal arguments appear to affect the management of territorial claims in systematic ways, and ending territorial claims seems to produce substantial improvements in relations between the former adversaries. The same general patterns seem to hold for river and maritime issues, as well as territorial issues, and these other issue types have more promising institutional contexts. Future research could benefit from considering additional issue types (including a recent effort to collect data on identity claims), as well as studying domestic and interstate issues.

Keywords: Territory, contentious issues, territorial claims, territorial disputes, borders, boundaries, geography, salience, empirical international relations theory


Modern history has been marked by repeated wars over territory, ranging from Alsace-Lorraine and the Danubian Principalities in the 19th century to the Golan Heights and Kashmir in the 20th century. Despite initial optimism that the end of the Cold War would usher in a new world order of cooperation, territorial issues have persisted. Iraq invaded Kuwait in 1990, Russia annexed Ukraine’s Crimean Peninsula in 2014, and disputes over islands in the South China Sea, East China Sea, and Sea of Japan have generated frequent incidents and threats. Scholars of international relations have noted the prominence of territorial issues as sources of armed conflict, leading to a productive body of academic research.

This article investigates this body of research, placing territorial issues in the context of the larger literature on contentious issues in world politics. I begin with the different ways that contentious issues have been conceptualized, beginning with early theoretical origins of this literature, and trace its development both theoretically and empirically. The theoretical scope initially narrowed, moving from all types of contentious issues in all types of foreign policy events to the role of territorial issues in armed conflict, but it has now broadened again to include both nonmilitarized interactions and nonterritorial issues such as maritime claims and river claims. More and better data sets have become available, too, allowing scholars to evaluate earlier propositions that were largely untestable, as well as to develop and test new propositions. While theoretical or empirical progress has not been smooth or linear, substantial progress has been made in terms of both contentious issues in a broad sense and territorial issues specifically, and we can see important directions for future progress.

Conceptualizing Contentious Issues

Issues, or “issue areas,” have been conceptualized in at least three different ways (Rosenau, 1967, p. 17; Hermann & Coate, 1982, p. 78). A value or substantive conception is based on the kinds of values or interests under contention, such as a distinction between contention over territorial sovereignty and over trade policy. In contrast, a process or procedural conception is based on the types of political processes that are used to manage such contention, and a unit conception is based on the types of units in which the contention occurs. Much of the earliest research on issues came from the emerging literature on foreign policy analysis and emphasized a process or unit conception. For example, Lowi (1964), Zimmerman (1973), and Rosenau (1967) focused on the nature of the policy process, with Lowi treating the foreign policy issue area as distinct from domestic issue areas, and Zimmerman and Rosenau discussing ways to bring foreign policy into the analysis more directly.

More recent work has tended to adopt a substantive conceptualization of issues, exemplified by Randle’s (1987, p. 1) widely cited definition of a contentious issue as “a disputed point or question, the subject of a conflict or controversy.” This basic approach allows researchers to study the impact of different types of substantive disagreement among actors, rather than assuming that all contention involves a struggle for power, security, or hegemony (as many realists believe) or a focus on the unique details of specific stakes (such as a particular piece of territory) in an idiographic fashion that renders comparative study impossible. Furthermore, as Diehl (1992) notes, conceptualizing issues as the substantive concern that states might choose to fight over ensures that the concept of issues is analytically distinct from the conditions that affect their choice to fight (such as the occurrence of an arms race or the competitors’ relative capabilities).

This conception of issues has been featured in research on the issues involved in militarized conflict. One approach has sought to identify the issues involved in modern wars, beginning with a list of conflicts and determining which types of disagreements were involved. Holsti (1991) and Luard (1986) defined issues as the stakes over which the combatants were contending, based primarily on the statements of leaders at the time. The issues that led to wars during their studies ranged from territorial sovereignty or protecting ethnic/religious minorities to dynastic succession or enforcing treaty terms. This approach offers the advantage of a broad range of possible issues, although there is little effort to develop a theoretical argument for how issues vary or how such variation affects international behavior, and the observed issues are limited to those that generated armed conflict.

Similarly, the Correlates of War (COW) project’s Militarized Interstate Dispute (MID) data set introduced issues when version 2 was released in the mid-1990s. This data set coded issues by identifying which states sought to revise the status quo ante through the dispute, recording “the principal object that the state sought to change” and distinguishing between attempts to change territorial sovereignty, specific government policies, or the makeup of a state’s governing regime (Jones, Bremer, & Singer, 1996, p. 178). Gibler (2017) expands on this general approach with a more fine-grained distinction, separating the COW’s “territorial” issue type into more than 20 subtypes of territorial issues based on the location of the territory (e.g., border area or colony), the motivation of the dispute (e.g., predatory/state making), or the type of activity in the dispute (e.g., sea or air violations). This general approach groups issues into categories that are believed to be theoretically meaningful rather than listing all issues that are identified in the data, although as with Holsti’s and Luard’s studies, the observed issues are limited to those that generated armed conflict.

Another approach is to specify the types of values under contention rather than listing the substantive issues. The International Crisis Behavior data set distinguishes among four general issue areas in coding the types of values that are threatened in crises: military-security, political-diplomatic, economic-developmental, and cultural-status (Brecher & Wilkenfeld, 1982). Similarly, the Comparative Research on the Events of Nations (CREON) foreign policy events data set distinguishes five sets of values that can be jeopardized in an event: security/military-physical-safety, economic wealth, respect/status, well-being/welfare, and enlightenment (Hermann & Coate, 1982). Such a categorization offers more theoretically meaningful categories than is possible with simple lists of issues, potentially corresponding to Abraham Maslow’s hierarchy of human needs or other theories about human behavior, although again, these data sets have been limited to the values at stake in specific types of events.

More recent studies has focused their data collection on the disagreement itself, rather than starting from a list of international events and identifying the issues involved in each. This approach began with territorial claims, as researchers sought to identify every case of disagreement over territorial sovereignty, regardless of whether the disagreement led to armed conflict or war. For the first time, these data sets allowed scholars to gain a more complete perspective on how issues are managed, as they included issues that were managed and settled peacefully, as well as those that led to military action. An example is the Issue Correlates of War (ICOW) project’s Territorial Claims data set (Hensel, 2001; Frederick, Hensel, & Macaulay, 2017), which requires explicit disagreement over a specific territory by official government policymakers. Huth (1996) and Huth and Allee (2002) offer a similar approach to identifying territorial disputes between countries. Focusing on a single type of issue also offers the advantage of allowing scholars to study variations in the salience or importance of each case, which is difficult to do when comparing numerous types of issues. Scholars of territorial claims, for example, have measured salience in terms of the contents or attributes of the claimed territory, such as the presence of economic resources, a strategic location, or identity ties between the claimant state and the residents of the territory.

The ICOW project later expanded data collection beyond territorial claims in order to facilitate comparison of how the different types of issues are managed. River claims require explicit disagreement over the usage of a shared river resource; maritime claims require explicit contention over the usage of a specific maritime zone; and identity claims require explicit contention over the status of an ethnic group that is shared by the claimant states (Hensel, Mitchell, Sowers, & Thyne, 2008; Hensel & Mitchell, 2017). These issues vary in the types of salience or importance that are typically associated with them, allowing comparative analysis of how issue characteristics affect issue management. Territorial issues are typically associated with tangible values such as survival, security, and wealth, as well as intangible values such as independence, culture/identity, and status/prestige/influence. River and maritime issues are primarily tangible in nature, as they focus on the usage of tangible resources or attributes such as freshwater, fisheries, and commercial navigation routes. Identity issues are primarily intangible, as they focus on the status of ethnic kin but rarely involve gains to a state’s wealth or security.

Contentious Issues Theory

Academic research on territory and other contentious issues can be traced to the 1960s, when scholars began to suggest that there are systematic differences in behavior when different types of contentious issues are at stake. The concept of issue areas emerged in the new field of foreign policy analysis, and much of the early work adopted procedural classifications of issue areas based on the processes by which values were allocated (e.g., Lowi, 1964; Zimmerman, 1973; Rosenau, 1967). These initial efforts made little impact on the foreign policy analysis literature, as even some of the scholars who proposed issue-based approaches rarely used such approaches in their subsequent research (Potter, 1980). More substantive conceptions of contentious issues have played a larger role in more recent studies of militarized conflict and conflict management, though, so now we examine the central elements of this approach.

The issues approach begins with the notion that foreign policy is issue-directed (Hensel, 2001, p. 82). O’Leary (1976) and Mansbach and Vasquez (1981b), among others, questioned the standard realist characterization that interstate relations can be treated as a unidimensional quest for power, security, or hegemony, or they can be distinguished between only “high politics” issues, involving military security, and “low politics” issues, involving everything else. As an alternative, O’Leary (1976, pp. 320–322) suggested that resolving specific contentious issues or allocating the values at stake in these issues is what motivates state behavior, and that “issues make a difference” (i.e., that states would exhibit different patterns of behavior across a range of issues). Similarly, Mansbach and Vasquez (1981a) suggested that there should be significant variation in conflict-cooperation patterns between specific stakes.

Most issues scholars also accept that “both cooperative and conflictual foreign policy tools are substitutable means used to pursue issue-related ends” (Hensel, 2001, p. 83). Early research on issues focused on broad patterns of conflict and cooperation using event data, but with the switch in focus to territorial issues, armed conflict received the vast majority of scholarly attention. The collection of new data sets on territorial disputes (Huth, 1996; Huth & Allee, 2002) and territorial claims (Hensel, 2001) allowed the expansion of issues research beyond armed conflict by investigating the origin, management, and ending of territorial issues, regardless of whether they lead to armed conflict.

Mansbach and Vasquez (1981b, pp. 282–287) note that issues can be managed or allocated via multiple mechanisms: force, bargains, votes, and principle. The notion of principle has not received much scholarly attention, as it focuses on pure consent between the adversaries based on some shared norm. The other mechanisms have been studied more widely, though, with force corresponding to the threat or use of militarized conflict, bargains corresponding to negotiations between the claimants (perhaps with the nonbinding involvement of a third-party mediator), and votes corresponding to submission of an issue to a binding arbitral or adjudicated decision. Scholars have sought to identify the conditions under which each of these settlement techniques (or allocation mechanisms) is most likely to be used to settle an issue.

Issue Salience

While early research using the issues approach suggested that there should be variations in conflict and cooperation across different stakes or issues, most of these earlier studies did not offer classifications or typologies of issues that would help to account for such variation. One effort to account for these characteristics came in Rosenau’s (1966) pre-theory of foreign policy. Rosenau argued that the foreign policymaking process would vary based on the tangibility of the policy goals sought and the tangibility of the means used to attain the policy objectives, leading to the identification of four distinct issue areas: territorial (tangible ends–intangible means), status (intangible ends–intangible means), human resources (intangible ends–tangible means), and nonhuman resources (tangible ends–tangible means). He suggested that actors contending over an issue would be more strongly motivated and more persistently active in pursuing the issue when the tangibility of means is greater and when the tangibility of ends is lesser. Vasquez (1983) elaborated on this framework to suggest that more tangible issues would be managed through more cooperative interaction overall.

Other scholars have sought to account for differences between issues in terms of the relative salience, or importance, of each issue to each actor. Randle (1987, p. 9) notes, “A matter becomes an issue because individuals or groups or groups of people place a value upon the subject and find that others place value on it.” Coplin, Mills, and O’Leary (1973) discussed issue salience as the percentage of time spent on an issue by the states’ leaders, with more salient or important issues being the ones that take up more time on the leaders’ agenda. Vasquez and Mansbach (1984) described salience as a critical factor in the management of an issue, arguing that low-salience issues are likely to be managed in a positive-sum fashion, while high-salience issues are more likely to be managed in a zero-sum fashion that makes peaceful settlement more difficult while making rivalry and/or war more likely. Later research (e.g., Goertz & Diehl, 1992; Vasquez, 1993; Hensel, 2001) suggested that higher salience should increase the risk of armed conflict over an issue, as leaders would be more willing to accept the costs and risks of military escalation over issues that they value highly than for less salient matters.

The notion of salience also helped to justify an increasing focus on territorial issues. Scholars suggested that territory is perhaps the most salient issue in world politics because it is the only issue that typically has high values of both tangible and intangible salience (Diehl, 1991; Vasquez, 1993; Hensel, 1996; Newman, 1999; Hassner, 2003; Goddard, 2006). Tangible salience of territory reflects such physical attributes or content as a militarily or economically strategic location, the presence of an economic resource, and the presence of a permanent population. Intangible salience includes more psychological factors, such as considering the territory to be part of one’s homeland (rather than a colony or dependency); sharing a religious, ethnic, or other identity connection with the territory or its inhabitants; and having a history of sovereignty over the territory, with the historical legacies and attachments that come with it. Because of the high overall salience of territory, how states handle their territorial issues is seen as an important contributor to a state’s reputation; showing weakness over a highly salient issue such as territory is considered a sign of weakness over other future issues. Finally, territory may become effectively indivisible because of strong, intangible connections to the land or its residents (Fearon, 1995; Toft, 2003). This approach is similar to Goertz and Diehl’s (1992) distinction between intrinsic salience (attributes of a territory that benefit any state that owns it—typically, tangible attributes such as economic or strategic value) and relational salience (attributes that only benefit one state—typically intangible attributes such as ethnic ties to the territory or its residents).

Moving beyond armed conflict, Hensel (2001, pp. 86–87) suggests that policymakers should be more likely to turn to bilateral negotiations or to welcome the involvement of nonbinding third-party assistance when a claimed territory is more salient, although binding third-party techniques should be rarer. Hensel et al. (2008) make a similar argument about variation in salience both within and across issue types. Issue types that are generally considered more salient, such as territory, should be more likely to lead to both military action and attempts at peaceful settlement. More salient issues within a given issue type, such as more valuable territories or rivers, also should be more likely to produce both military action and peaceful settlement attempts.

Hensel and Mitchell (2005) extend Rosenau’s early thoughts about issue tangibility by distinguishing between the tangible and intangible salience of territorial claims. Rather than labeling an entire issue type based on tangible or intangible ends of means, they separate salience into two components. Tangible salience is based on the presence of a permanent population, natural resources, and strategic value of a territory, while intangible salience reflects the existence of territory that is considered homeland rather than a colony or dependency, identity ties with the territory and its residents, and historical sovereignty over the territory. Expanding on Rosenau (1966) and Vasquez (1983), they suggest that the greater the intangible salience of a claimed territory, the more difficult the territorial claim should be to resolve peacefully, and the more likely the claimants should be to initiate and escalate armed conflict.

Scholars also have developed theories about specific elements of territorial salience. Such research does not necessarily have clear implications for nonterritorial issues, but it offers important contributions to the understanding of territorial issue management. For example, rather than treating salience as a single concept, Huth (1996) suggests that different elements of territorial salience can have different effects on claim management. When the claimed territory has a strategic location or includes residents who share ethnic identity with the challenger state, Huth (1996, pp. 49–52) suggests that the challenger state will be more likely to use diplomatic or military pressure against the target and less likely to seek claim resolution by compromise or conciliation. In contrast, when the territory contains economically valuable resources, the challenger should be less likely to use diplomatic or military pressure and more likely to pursue compromise or conciliation. Unlike strategic military positions or unification with ethnic kin, satisfactory access to the resource might be worked out without complete sovereignty over the territory (Huth, 1996, pp. 52–53).

Huth and Allee (2002) refocus the earlier argument with more consideration of domestic political considerations. For example, democratic leaders should be more likely than their authoritarian counterparts to pursue claims to territory containing their ethnic kin by pursuing talks and (especially) armed conflict than by maintaining the status quo, less likely to make concessions in talks, and more likely to escalate military confrontations (Huth & Allee, 2002, pp. 78–80). Furthermore, when the challenger has an ethnic tie to the territory, it may see binding legal settlement as desirable despite the risk of losing in a legally binding ruling, as such issues will be so salient to domestic audiences that any concession in a bilateral deal with the adversary would be politically difficult.

Issue Context

Issue scholars also have suggested that the international context matters systematically, beyond the standard scholarly treatment of context as a series of control variables. Brewer (1973) refers to this as “issue context” and suggests that both prior involvement over the same issue and concurrent problems related to the issue will affect the actions of foreign policymakers. Past interaction over an issue also plays an important role in Rosenau’s (1967) discussion of the distinction between foreign and domestic policy issue areas. For citizens, foreign policy issues are described as typically lying outside the ordinary citizen’s awareness, meaning that such issues are unlikely to inspire strong motivations because they do not impinge on the citizen’s interests, activities, or aspirations. This suggests a major motivational gap between citizens and their leaders over foreign policy issues because policymakers are much more focused on events beyond their borders. An exception can arise, though, for foreign policy questions that begin to require the utilization of a society’s personnel and wealth, as when military force is used and citizens begin to feel the effects of the issue personally. In such cases, citizens are likely to become activated politically over the issue and to take a greater interest in the bargaining over the issue’s resolution (much as they do in more traditional domestic policy issues). This activation element has the potential to inform research on issues, as it offers a way for interactions over an issue to change the policymaking process once the public begins to take notice, although this has not been addressed directly in most research.

Along these general lines, Vasquez (1993) and Hensel (2001) suggest that militarized conflict over a territorial claim should become more likely when there is a longer history of recent conflict and of failed peaceful settlement attempts. Hensel (2001) suggests that when peaceful techniques have failed to settle an issue, as well as when the adversaries have turned to armed conflict more often over the issue, nonbinding third-party conflict management such as mediation should also be more likely. Huth (1996) makes similar arguments about situations where negotiations over the territory have become stalemated.

Huth (1996, pp. 55–57) also suggests that when the target state has begun taking action to change the status quo in the claimed territory, the challenger should be more likely to use diplomatic or military pressure over the claim and less likely to pursue settlement by compromise or conciliation. When the challenger has a longer history of defeat or stalemate in military confrontations with the adversary, it should be less likely to use diplomatic or military pressure and more likely to pursue settlement by compromise or conciliation. Furthermore, the more militarized disputes are between the challenger and target states, the more likely the challenger should be to use diplomatic or military pressure, and the less likely to pursue settlement by compromise or conciliation. In a follow-up study, Huth and Allee (2002, pp. 77–78) also suggest that democratic leaders should be more likely than their authoritarian counterparts to respond to stalemated negotiations with further talks rather than military coercion, and less likely to follow intransigence with concessions.

Institutional Context

Mansbach and Vasquez (1981b, p. 69) argue that contention over issues is also shaped by the institutional context in which allocation decisions must be made. Elaborating on this, Vasquez (1993, pp. 148–150) emphasizes the prevailing norms in international politics. When there is widespread consensus on the rules or principles for managing an issue, the issue can be managed more peacefully. For example, when there was not widespread agreement on the rules for dynastic succession, European powers frequently turned to war to resolve the question after the death of a ruler. Similarly, if most major actors should agree on the basis for appropriate or inappropriate territorial claims, then such claims should be less likely to arise and be more likely to be managed peacefully when they do.

This notion of the normative or institutional context has been addressed in several ways. Hensel (2001, p. 89) examined the network of multilateral treaties and institutions that are shared by the claimant states, suggesting that peaceful conflict management should be more likely and more successful when they share more institutions that call for peaceful conflict management between member-states. Mitchell and Hensel (2007) go further, suggesting that sharing such institutions should increase states’ ability to reach agreement over their issues, as well as compliance with any agreement that might be reached.

Focusing specifically on territorial claims, Zacher (2001) and Hensel, Allison, and Khanani (2009) argue that as global support for the territorial integrity norm increases, states should be less likely to pursue militarized conflict over territory. Owsiak and Mitchell (2017) also distinguish between the institutional context in multiple issue types, suggesting that territorial claims (the most informal context) should typically see bilateral negotiations and arbitration, while river claims—with an intermediate level of formalization—should see more nonbinding third-party settlement activity and maritime claims. The most formalized, as reflected in the UN Convention on the Law of the Sea (UNCLOS), should see more multilateral negotiations and legal processes. This is consistent with Nemeth, Mitchell, Nyman, and Hensel (2014), who examine UNCLOS as a global institution that promotes cooperation over maritime issues.

Empirical Analysis of Contentious Issues

The earliest research on issue areas in the foreign policy analysis literature made limited but important contributions to our understanding by investigating the extent to which international behavior varies across issue areas. Brewer (1973) coded issue-related attributes for events data on threats to American objectives concerning European integration or the Atlantic alliance, and concluded that foreign policy behavior did indeed vary across issues. Coplin, Mills, and O’Leary (1973) distinguished between six specific issues, ranging from Vietnam and Middle East peace to territory and military aid, and found significant differences in conflict-cooperation patterns in the same dyads when different issues were at stake. O’Leary (1976) found that states showed significantly different patterns of behavior with different dyadic partners, suggesting that certain dyads face more issue variation than others (represented by higher standard deviations in friendship-hostility scores across events), although this study did not code the specific issues involved. Similarly, Mansbach and Vasquez (1981a) found a high correlation between the 78 distinct stakes that they identified in a new set of events data involving the United States or West Germany and conflict-cooperation patterns, despite having no theoretical categorization of issues/stakes and no measurement of the salience of each stake.

Several early articles also attempted to evaluate the propositions about tangible and intangible issues in Rosenau’s (1966) pretheory. Brewer (1973) found little support for Rosenau’s expectations in a data set of events related to European integration and the Atlantic alliance, although the nature of the events being studied meant that only two of Rosenau’s four tangibility categories were included in the data set; there were no events related to territory or human resources. Vasquez (1983) used tangibility to run a follow-up analysis of the data set that had been used by Mansbach and Vasquez (1981a), which included cases from all four of Rosenau’s categories, and found stronger results. As Rosenau suggested, more tangible issues appeared to be more cooperative, and more intangible issues more conflict-prone.

While event data–based analyses suggested that patterns of international interactions vary across different issues, the issues approach did not start to reach mainstream acceptance until scholars started to move beyond event data to studying the issues involved in armed conflicts. This began with efforts to compile the issues involved in modern wars since 1400 (Luard, 1986) or 1648 (Holsti, 1991; Vasquez, 1993). Each study noted that territorial issues have been prominent throughout history, although more internal matters like government composition and national liberation have become more common since World War II. Mitchell and Prins (1999) undertook a similar effort for militarized disputes between democracies since World War II, concluding that jointly democratic pairs have largely been able to remove territorial issues from the agenda, but that maritime and fishery issues have been quite common between them.

Such studies did not offer any direct confirmation for hypotheses drawn from contentious issues theory, although the prominence of territorial issues was certainly consistent for the expectations that such issues are more salient than other issue types, and that more salient issues are more likely to lead to armed conflict than less salient issues. These studies did lead scholars to investigate the connection between territory and conflict more completely, though, particularly once the MID data set was updated to include the basic types of issues involved in each dispute. Militarized disputes involving territorial issues are much more likely than nonterritorial disputes to produce fatalities or to escalate to full-scale war, as well as to lead to recurrent conflict between the same adversaries. Moreover, these findings hold up after considering the impact of geographic contiguity, as well as many other factors that might be thought to produce escalation (e.g., Hensel, 1996, 2012; Senese & Vasquez, 2008; Vasquez & Henehan, 2011).

Issue Salience

Moving beyond broad differences between issues, scholars have examined the role of issue salience in a number of different ways. Hensel (2001) measured the salience of territorial claims with a 12-point index that includes a number of characteristics of the claimed territory that should increase its value to the challenger and/or target state. Higher values on this salience index significantly increase the probability of militarized conflict, bilateral negotiations, and nonbinding third-party management techniques, with no systematic impact on the probability of binding third-party arbitration or adjudication.

Hensel and Mitchell (2005) break this 12-point salience index into separate 6-point indices of tangible and intangible salience. The overall salience of the claimed territory significantly reduces the likelihood of reaching agreement in peaceful settlement attempts, while increasing the likelihood of three different forms of militarized conflict over the claim. Tangible salience has the same effects, reducing the likelihood of agreement while increasing all three forms of militarized conflict. Intangible salience has an even stronger impact on the two most severe forms of militarized conflict, with roughly double the substantive impact on escalation, although to the authors’ surprise, agreement seemed to be even more likely when intangible salience was higher.

Other work has disaggregated the concept of salience, examining the impact of each indicator of claim salience separately. Goertz and Diehl (1992) find that the intrinsic value of an exchanged territory (measured by area and population) tends to increase the risk of armed conflict, both during the exchange and in future relations between the same states. Furthermore, the relational value of the territory (whether it is considered homeland or dependent territory) affects the risk of future conflict, particularly with respect to the state that lost the territory. Huth (1996) finds that three different indicators—strategic location, ethnic similarity between the states, and the presence of economic resources—increase the likelihood that a claim will emerge over territory along an international border, although a fourth—ties between the challenger state and an ethnic group along the border—does not. Three of these four indicators increase the level of armed conflict over the territory once a claim has begun, which reduces the likelihood of peaceful settlement. The fourth, the presence of resources, has the opposite effect, reducing the level of armed conflict and increasing the likelihood of peaceful settlement. Tir (2006) similarly finds that when two states engage in a territorial claim after exchanging territory, they are more likely to begin armed conflict when the territory has economic value; ethnic ties to the territory have a weaker effect on conflict and strategic value of the territory has little systematic impact on future conflict.

Focusing more on domestic political factors, Huth and Allee (2002) find that the impact of ethnic ties with the challenger depends on the regime type of the challenger state. Ethnic ties by themselves do not have a significant impact on the likelihood of negotiations or armed conflict over a territory, but democratic challengers are significantly more likely than autocrats to pursue both negotiations and armed conflict relative to the status quo. Similarly, while ethnic ties generally reduce the likelihood of concessions in negotiations over a claim, democratic leaders are even less likely to offer concessions when they have ethnic ties to the territory. There is no systematic impact of democracy on the likelihood of conflict escalation when a state has ethnic ties to the territory, though. Allee and Huth (2006) find that submission of a case to binding arbitration or adjudication is significantly more likely when the challenger has ethnic ties to the territory, as the binding settlement would offer domestic political cover that can protect the leader politically if concessions must be made to settle the issue peacefully.

These basic patterns of salience that have emerged from studying territorial issues have generally held up as data has been collected for other types of contentious issues. Hensel et al. (2008) find that territorial, river, and maritime issues are largely managed similarly. There are differences between issues, with territorial claims—widely regarded as the most salient issue type overall—being the most likely to become militarized (see also Hensel & Mitchell, 2017). Like territorial issues, though, both river and maritime issues are more likely to become militarized when issue salience is greater, reflecting the usage of a disputed river for such purposes as irrigation or hydroelectric power generation or the usage of a disputed maritime zone for such purposes as fishing or oil/gas extraction. All three issue types are also more likely to see peaceful conflict management efforts when the issue in question is more salient.

Issue Context

Hensel (2001) finds that the recent management of a territorial claim has an important impact on contemporary decisions on claim management. Greater numbers of recent militarized conflicts or failed negotiations increase the probability of militarized conflict, bilateral negotiations, or nonbinding third-party activities such as mediation. A war in the previous decade increases nonbinding third-party activities while decreasing the likelihood of militarized conflict. A greater number of successful peaceful settlement attempts—typically involving procedural or functional matters rather than addressing the substance of the claim—increases the probability of binding third-party arbitration or adjudication. These general patterns also hold for river and maritime issues as well as territory; Hensel et al. (2008) find that recent histories of both armed conflict and peaceful settlement attempts generally increase the probability of both militarized and peaceful settlement techniques.

Similarly, Huth (1996) finds that the level of armed conflict over a territorial claim is higher when there is a stalemate in negotiations over the territory and when the target state is attempting to change the status quo in the territory. The level of conflict is also higher when there have been more prior conflicts between the claimant states, and lower when the target has previously defeated the challenger in armed conflict. The likelihood of peaceful settlement is higher when the challenger has previously been defeated, but lower when there have been more prior armed conflicts and when the target is attempting to change the status quo.

Focusing more on domestic politics, Huth and Allee (2002) find less support than expected for the difference between democratic and autocratic leaders in responding to the issue context. There is no systematic difference between these two regime types in response to stalemated negotiations or to histories of armed conflict/rivalry with respect to negotiations or armed conflict over the claim. There is also little difference between regime types in most of their analyses of offering concessions during negotiations or of escalation in armed conflict.

Institutional Context

As with claim salience, the institutional context within which an issue is managed has been studied in many different ways. One approach is to measure shared institutions that call for peaceful conflict management between member-states, regardless of the issue at stake. Hensel (2001) finds that sharing more such institutions increases the probability of nonbinding third-party management of a territorial claim, suggesting that shared institutions can affect the behavior of member-states, although there was no indication of whether the institution itself actually became involved in the nonbinding management activity. Mitchell and Hensel (2007) also find that sharing more such institutions increases the probability both that a peaceful settlement attempt will end in agreement and that both sides will comply with the agreement.

Beyond general institutional provisions for peaceful conflict management, scholars have compared the global institutional context for managing specific types of issues. There are no global institutions that specifically manage territory and borders around the world, but territorial claims might be managed through the normative context. Zacher (2001) has suggested that a norm of territorial integrity has emerged and strengthened over time, under which states are less likely to make territorial demands of other states and even less likely to pursue these demands through military force. Zacher found preliminary evidence to support this suggestion, with successful territorial conquests becoming very rare by the late 20th century; Fazal (2004) similarly notes that cases of state death have become far less common since 1945. Hensel, Allison, and Khanani (2009) attempted to measure the strength of the norm quantitatively by coding shared memberships in international treaties and institutions that require respect for the territorial integrity of fellow members, and they found only weak support for the territorial integrity norm with respect to the outbreak of militarized disputes over territorial issues. Frederick, Hensel, and Macaulay (2017) do not explicitly test the impact of the territorial integrity norm in their overview of territorial claims between 1816–2001, but they do note several patterns that are consistent with this norm. The number of territorial claims per state in the international system is now the lowest that it has been since the early 19th century, as many claims have ended and few new claims have arisen to replace them, and fewer territorial claims have been militarized in the post–Cold War era (1990–2001) than in any earlier era since 1816.

Other issues besides territory have seen the emergence of more meaningful institutions, which appear to affect their management. River claims are addressed by the U.N. Convention on Non-Navigational Uses of International Watercourses, which includes a number of provisions aimed at avoiding or managing international disputes over shared rivers. However, this convention has not attracted much international support as yet, with a gap of 17 years after signature before it entered into force with the 35th ratification, and most states with shared rivers have not signed or ratified it (Owsiak & Mitchell, 2017). Conca (2006) and Conca, Wu, and Mei (2006), similarly, note that there has been little progress toward effective global agreements over international rivers, but that states have been able to create formal international regimes for individual rivers or basins.

Maritime claims are addressed by the far more meaningful UNCLOS, which includes provisions meant to avoid or manage international disputes over maritime zones, and which has been ratified by many more states than the river convention. Owsiak and Mitchell (2017) find that issues managed by more formal institutions see more third-party conflict management, with the somewhat formal river claims seeing more nonbinding third-party claim management than the less formal territorial claims, and with the most formal maritime claims seeing much more binding legal processes and multilateral negotiations. Nemeth et al. (2014) also find that shared membership in UNCLOS greatly reduces the outbreak of new maritime claims and increases the third-party management of such claims, although it does not have a systematic impact on claim militarization.

Extensions of Research on Contentious Issues

The literature discussed thus far has explicitly tried to study the management of contentious issues, but many scholars have branched off in different directions with issue data. A great deal of research has focused on the militarized or peaceful management of contentious issues, often using issues data to test other hypotheses. I will not focus on peaceful settlement techniques in much detail, though, as that is already covered by Krista Wiegand’s entry in this volume, “Conflict Management of Territorial Disputes.”

Territorial Issues

Carter and Goemans (2011) collected original data on the location of borders between administrative units, both in the contemporary world and historically. They argue that choosing borders based on previous administrative lines tends to increase stability, and find that new international borders drawn along previous internal or external administrative borders tend to see fewer territorial claims and less militarization of those claims. Abramson and Carter (2016) focus on a different impact of historical border precedents, finding that the presence of historical borderlines near the current border increases the likelihood of new territorial claims. Schultz (2017) and Goemans and Schultz (2017) also geocode territorial claims, offering an interesting demonstration of the potential that geocoding has to understand the origins, salience, and impact of territorial claims. In particular, territorial claims are more likely to begin in Africa, when a border partitions an ethnic group; borders following clear focal principles like rivers are less likely to be challenged, and natural resources play little systematic role in claim initiation.

Several articles have examined the impact of international law on the management and settlement of territorial issues. They emphasize the legal bases of territorial claims, examining the number of legal principles supporting each side’s claim. When these legal principles unambiguously favor one side’s claim over the other’s, the side with the stronger claim tends to push for negotiations rather than using force, and the claim is more likely to be settled peacefully than when the claims are more equal in nature (Huth, Croco, & Appel, 2011). If armed conflict does occur, though, the state with the stronger legal claim tends to be more likely to escalate the conflict to defend its claim (Huth, Croco, & Appel, 2012). International legal considerations can also support territorial settlements by making a renewed challenge politically difficult, particularly when the state that lost territory has another territorial claim where it has a legal advantage over its opponent (Prorok & Huth, 2015).

Finally, given the high overall salience of territorial issues, scholars have long speculated that settling these issues should lead to substantial improvement in relations between former enemies (e.g., Vasquez, 1993). Simmons (2005) and Schultz (2014a) note that bilateral trade between the former claimants appears to increase substantially after the settlement of territorial claims. Owsiak (2012) and Schultz (2014b) find that settling the border between two states significantly reduces the risk of future militarized conflict between them. Gibler (2012) also reports a “territorial peace,” noting that settling borders and ending territorial threats greatly increases the prospects for democratization; he suggests that settled borders may be a virtual precondition for the well-known democratic peace.

Other Issues

Although territorial claims have received the most scholarly attention by far, a growing body of literature examines the management of international rivers. The majority of this research has focused on the signature and impact of river treaties, rather than on river claims. Conca (2006) and Conca, Wu, and Mei (2006) note that there has been little progress toward a global regime governing international rivers, in terms of either global agreements or common principles shared by local or regional agreements, but that there has been some progress in terms of individual rivers or basins. Tir and Ackerman (2009) examine the conditions under which states are most likely to sign river treaties, Tir and Stinnett (2011) examine the specific institutional provisions of treaties that are signed, and Zawahri and Mitchell (2011) examine the different factors that lead states in multilateral river basins to sign bilateral or multilateral treaties over the basin. Together, these studies offer a great deal of insight into the institutional context governing river issues, even if they have not directly examined the river issues themselves.

Other research has examined interactions between states that share rivers. Wolf (1998) notes that armed conflict over rivers has been quite rare, and that states are much more likely to cooperate than to fight over their shared rivers. Brochmann and Gleditsch (2012) find that armed conflict between states sharing rivers is more likely when their rivers follow an upstream-downstream pattern and when they share a larger basin, and Tir and Stinnett (2012) note that water scarcity increases the risk of conflict between neighbors sharing a river, but neither of these studies limit the conflicts to those that specifically involve river issues. River treaties can be quite helpful, as Tir and Stinnett (2012) note that institutionalized river treaties offset the risk of conflict, and Dinar, Dinar, and Kurukulasuriya (2011) find that river treaties increase cooperation among states sharing rivers.

After the ICOW project released the initial version of the river claims data, scholars began to focus specifically on explicit contention over rivers, rather than just general patterns of conflict and cooperation between states sharing rivers. Hensel, Mitchell, and Sowers (2006) find that greater water scarcity increases the likelihood of both militarized conflict and third-party conflict management efforts during ongoing river claims, while river-specific treaties reduce conflict and increase the effectiveness of conflict management efforts. Brochmann and Hensel (2009) report that greater water scarcity increases not only armed conflict over river claims, but also negotiations over the claim, echoing Wolf’s (1998) finding, and that relevant river treaties greatly increase negotiations. Brochmann and Hensel (2011) also find that water scarcity reduces the effectiveness of negotiations over river claims, but that rivers with higher salience generally see more effective negotiations, and Mitchell and Zawahri (2015) find that details of river treaties and institutions can greatly increase the successful management and resolution of river claims.

Maritime issues are also beginning to receive scholarly attention. Ásgeirsdóttir (2016) argues that maritime issues have relatively low salience, leading to a focus on political and economic transaction costs to help explain which U.S. maritime borders have been settled successfully. Ásgeirsdóttir and Steinwand (2015) also focus on decisions to pursue bilateral versus multilateral dispute settlement with respect to maritime boundaries. Turning to armed conflict, Nyman (2015) finds that armed conflict over maritime issues has become more likely with advances in offshore drilling technology, which have opened up the possibility of exploiting previously unreachable resources and increased incentives to ensure sovereignty over offshore oil fields. Nemeth et al. (2014) find that neither UNCLOS membership not declaring exclusive economic zones (EEZs) affects the risk of armed conflict over maritime issues, but that UNCLOS membership reduces the risk of new maritime claims and increases third-party management of such claims, and that EEZs increase the chances of success in bilateral negotiations over the maritime issue.


The academic literature on contentious issues has made a great deal of progress since its origins in the foreign policy analysis literature in the 1960s. Investigations of the issues involved in militarized disputes, crises, and wars consistently highlighted territorial issues as the most dangerous issues in the modern era, drawing the attention of scholars and leading to both theoretical and empirical innovation. This innovation was spurred by advances in data collection, first by coding the issues involved in existing data sets of armed conflicts, and then by coding original data sets of territorial claims that included claims that never became militarized, as well as both peaceful and militarized interactions over the claims.

Theoretical development on contentious issues has generally focused on three broad areas. Issue salience, or the importance of the specific issue under contention, has been perhaps the most prominent emphasis of issues research. Issue context, or recent interactions over the same issue, has generated important insights into the dynamics of issue management. The institutional context, or the set of norms and institutions within which contention takes place, also has proved to be an important influence on issue management, as well as an important set of differences between different issue types.

Beyond these three broad areas, research in the past decade has begun to move in new directions. Research on territory has begun to use geocoding to examine everything from the exact location of oil deposits to the existence of historical borders that could be used to justify new territorial claims. Other territorial research has begun to examine the specific international legal doctrines supporting each side’s case in a territorial claim in order to determine whether the relative strength of the two cases affects behavior, as well as to examine the political and economic consequences of settling territorial claims. In addition, researchers have begun focusing more explicitly on nonterritorial issues, particularly river and maritime claims, with an emphasis on the institutional context of UNCLOS as opposed to the variety of bilateral and multilateral river treaties and the lack of formal institutions addressing territory and borders.

One potentially fruitful direction for future research is expansion to the study of issues beyond the interstate level. Rosenau’s (1966, pp. 193–194) categorization of issues based on the tangibility of means and ends was explicitly designed to apply to any level of politics: international, national, and even local. Some of his examples included a dispute over water rights between Arizona and California (territorial), racial conflict within South Africa (status), local teacher-training programs (human resources), and housing, highway, and agricultural programs (nonhuman resources). Almost all research on contentious issues has focused on relations between states, though, or at best on relations between a state and a nonstate actor in the context of event data (Mansbach & Vasquez, 1981b) or state conflicts with secessionist groups (Walter, 2006). Relations between political actors within a single state raise the possibility of entirely different types of institutional contexts, replacing the omnipresent state of anarchy in international relations with various domestic arrangements governing the units.

Finally, one other area that future research could benefit is the study of additional issue types. Territorial, river, and maritime claims offer important differences in salience and in the institutional context, but all three have strong tangible salience. The ICOW project has just begun collecting data on identity claims, where the states contend over the status of a shared ethnic group. Such claims typically take on high values of intangible salience due to the identity connection between the challenger state and the ethnic group in question, but low values of tangible salience because there is little to be gained physically from the claim, offering a useful comparison to the existing issue data sets. Data collection has not yet begun on any issues that are considered to be relatively low in both tangible and intangible salience, but that might be a productive future research endeavor, which would allow a more complete comparison of issue types.

Further Reading

Boggs, S. W. (1940). International boundaries: A study of boundary functions and problems. New York: Columbia University Press.Find this resource:

Bowman, I. (1946). The strategy of territorial decisions. Foreign Affairs, 24(2), 177–194.Find this resource:

Diehl, P. F. (Ed.). (1999). A road map to war. Nashville: Vanderbilt University Press.Find this resource:

Hill, N. (1945). Claims to territory in international relations. New York: Oxford University Press.Find this resource:

Kacowicz, A. M. (1994 ). Peaceful territorial change. Columbia: University of South Carolina Press.Find this resource:

Kahler, M., & Walter, B. F. (Eds.). (2006). Territoriality and conflict in an era of globalization. Cambridge, U.K.: Cambridge University Press.Find this resource:

Luard, E. (1970). The international regulation of frontier disputes. New York: Praeger.Find this resource:

Mandel, R. (1992). Sources of international river basin disputes. Conflict Quarterly, 12(4), 25–56.Find this resource:

Prescott, J. R. V. (1987). Political frontiers and boundaries. Boston: Unwin Hyman.Find this resource:

Starr, H. (2005). Territory, proximity, and spatiality: The geography of international conflict. International Studies Review, 7(3), 387–406.Find this resource:

Tir, J. (2010). Territorial diversion: Diversionary theory of war and territorial conflict. Journal of Politics, 72(2), 413–425.Find this resource:


Abramson, S. F., & Carter, D. B. (2016). The historical origins of territorial disputes. American Political Science Review, 110(4), 675–698.Find this resource:

Allee, T. L., & Huth, P. K. (2006). Legitimizing dispute settlement: International legal rulings as domestic political cover. American Political Science Review, 100, 219–234.Find this resource:

Ásgeirsdóttir, Á. (2016). Settling of the maritime boundaries of the United States: Cost of settlement and the benefits of legal certainty. Marine Policy, 73, 187–195.Find this resource:

Ásgeirsdóttir, Á., & Steinwand, M. (2015). Dispute settlement mechanisms and maritime boundary settlements. Review of International Organizations, 10, 119–143.Find this resource:

Brecher, M., & Wilkenfeld, J. (1982). Crises in world politics. World Politics, 34(3), 380–417.Find this resource:

Brewer, T. (1973). Issue and context variations in foreign policy. Journal of Conflict Resolution, 17(1), 89–114.Find this resource:

Brochmann, M., & Gleditsch, N. P. (2012). Shared rivers and conflict: A reconsideration. Political Geography, 31(8), 519–527.Find this resource:

Brochmann, M., & Hensel, P. R. (2009). Peaceful management of international river claims. International Negotiation, 14(2), 391–416.Find this resource:

Brochmann, M., & Hensel, P. R. (2011). The effectiveness of negotiations over international river claims. International Studies Quarterly, 55(3), 859–882.Find this resource:

Carter, D. B., & Goemans, H. E. (2011). The making of the territorial order: New borders and the emergence of interstate conflict. International Organization, 65(2), 275–309.Find this resource:

Conca, K. (2006). Governing water: Contentious transnational politics and global institution building. Cambridge, MA: MIT Press.Find this resource:

Conca, K., Wu, F., & Mei, C. (2006). Global regime formation or complex institution building? The principled content of international river agreements. International Studies Quarterly, 50(2), 263–285.Find this resource:

Coplin, W. D., Mills, S., & O’Leary, M. K. (1973). The PRINCE concepts and the study of foreign policy. In P. J. McGowan (Ed.), Sage international yearbook of foreign policy studies (vol. 1, pp. 73–103). Beverly Hills, CA: SAGE.Find this resource:

Diehl, P. F. (1991). Geography and war: A review and assessment of the empirical literature. International Interactions, 17(1), 1–27.Find this resource:

Diehl, P. F. (1992). What are they fighting for? The importance of issues in international conflict research. Journal of Peace Research, 29, 333–344.Find this resource:

Dinar, S., Dinar, A., & Kurukulasuriya, P. (2011). Scarcity and cooperation along international rivers: An empirical assessment of bilateral treaties. International Studies Quarterly, 55(3), 809–833.Find this resource:

Fazal, T. (2004). State death in the international system. International Organization, 58(2), 311–344.Find this resource:

Fearon, J. D. (1995). Rationalist explanations for war. International Organization, 49(3), 379–414.Find this resource:

Frederick, B. A., Hensel, P. R., & Macaulay, C. (2017). The issue correlates of war territorial claims data, 1816–2001. Journal of Peace Research, 54(1), 99–108.Find this resource:

Gibler, D. M. (2012). The territorial peace: Borders, state development, and international conflict. Cambridge, U.K.: Cambridge University Press.Find this resource:

Gibler, D. M. (2017). What they fight for: Specific territorial issues in militarized interstate disputes, 1816–2001. Conflict Management and Peace Science, 34(2), 194–211.Find this resource:

Goddard, S. E. (2006). Uncommon ground: Indivisible territory and the politics of legitimacy. International Organization, 60(1), 35–68.Find this resource:

Goemans, H. E., & Schultz, K. A. (2017). The politics of territorial claims: A geospatial approach applied to Africa. International Organization, 71(1), 31–64.Find this resource:

Goertz, G., & Diehl, P. F. (1992). Territorial changes and international conflict. London: Routledge.Find this resource:

Hassner, R. E. (2003). To halve and to hold: Conflicts over sacred space and the problem of indivisibility. Security Studies, 12(4), 1–33.Find this resource:

Hensel, P. R. (1996). Charting a course to conflict: Territorial issues and militarized interstate disputes, 1816–1992. Conflict Management and Peace Science, 15, 43–73.Find this resource:

Hensel, P. R. (2001). Contentious issues and world politics: The management of territorial claims in the Americas, 1816–1992. International Studies Quarterly, 45, 81–109.Find this resource:

Hensel, P. R. (2012). Territory: Geography, contentious issues, and world politics. In J. A. Vasquez (Ed.), What do we know about war? (2d ed., pp. 3–26). Lanham, MD: Rowman and Littlefield.Find this resource:

Hensel, P. R., Allison, M., & Khanani, A. (2009). Territorial integrity treaties and armed conflict over territory. Conflict Management and Peace Science, 26(2), 120–143.Find this resource:

Hensel, P. R., & Mitchell, S. M. (2005). Issue indivisibility and territorial claims. GeoJournal, 64, 275–285.Find this resource:

Hensel, P. R., & Mitchell, S. M. (2017). From territorial claims to identity claims: The Issue Correlates of War (ICOW) project. Conflict Management and Peace Science, 34(2), 126–140.Find this resource:

Hensel, P. R., Mitchell, S. M., & Sowers, T. E., II (2006). Conflict management of riparian disputes: A regional comparison of dispute resolution. Political Geography, 25(4), 383–411.Find this resource:

Hensel, P. R., Mitchell, S. M., Sowers, T. E., II, & Thyne, C. L. (2008). Bones of contention: comparing territorial, maritime, and river issues. Journal of Conflict Resolution, 52(1), 117–143.Find this resource:

Hermann, C. F., & Coate, R. A. (1982). Substantive problem areas. In P. Callahan, L. P. Brady, & M. G. Hermann (Eds.), Describing foreign policy behavior (pp. 77–114). Beverly Hills, CA: SAGE.Find this resource:

Holsti, K. J. (1991). Peace and war: Armed conflicts and international order, 1648–1989. New York: Cambridge University Press.Find this resource:

Huth, P. K. (1996). Standing your ground: Territorial disputes and international conflict. Ann Arbor: University of Michigan Press.Find this resource:

Huth, P. K., & Allee, T. (2002). The democratic peace and territorial conflict in the twentieth century. Cambridge, U.K.: Cambridge University Press.Find this resource:

Huth, P. K., Croco, S. E., & Appel, B. J. (2011). Does international law promote the peaceful settlement of international disputes? Evidence from the study of territorial conflicts since 1945. American Political Science Review, 105(2), 415–436.Find this resource:

Huth, P. K., Croco, S. E., & Appel, B. J. (2012). Law and the use of force in world politics: The varied effects of law on the exercise of military power in territorial disputes. International Studies Quarterly, 56(1), 17–31.Find this resource:

Jones, D. M., Bremer, S. A., & Singer, J. D. (1996). Militarized interstate disputes, 1816–1992: Rationale, coding rules, and empirical patterns. Conflict Management and Peace Science, 15, 163–213.Find this resource:

Lowi, T. (1964). American business, public policy, case studies, and political theory. World Politics, 16(4), 677–715.Find this resource:

Luard, E. (1986). War in international society. London: I. B. Tauris.Find this resource:

Mansbach, R., & Vasquez, J. A. (1981a). The effect of actor and issue classifications on the analysis of global conflict. Journal of Politics, 43(3), 861–874.Find this resource:

Mansbach, R., & Vasquez, J. A. (1981b). In search of theory: A new paradigm for global politics. New York: Columbia University Press.Find this resource:

Mitchell, S. M., & Hensel, P. R. (2007). International institutions and compliance with agreements over contentious issues. American Journal of Political Science, 51(4), 721–737.Find this resource:

Mitchell, S. M., & Prins, B. (1999). Beyond territorial contiguity: An examination of the issues underlying democratic interstate disputes. International Studies Quarterly, 43, 169–183.Find this resource:

Mitchell, S. M., & Zawahri, N. (2015). The effectiveness of treaty design in addressing water disputes. Journal of Peace Research, 52(2), 187–200.Find this resource:

Nemeth, S. C., Mitchell, S. M., Nyman, E. A., & Hensel, P. R. (2014). Ruling the sea: Managing maritime conflicts through UNCLOS and exclusive economic zones. International Interactions, 40(5), 711–736.Find this resource:

Newman, D. (1999). Real places, symbolic spaces: Interrelated notions of territory in the Arab-Israeli conflict. In P. F. Diehl (Ed.), A road map to war (pp. 3–34). Nashville: Vanderbilt University Press.Find this resource:

Nyman, E. A. (2015). Offshore oil development and maritime conflict in the 20th century: A statistical analysis of international trends. Energy Research and Social Science, 6, 1–7.Find this resource:

O’Leary, M. (1976). The role of issues. In J. N. Rosenau (Ed.), In search of global patterns (pp. 318–325). New York: Free Press.Find this resource:

Owsiak, A. O., & Mitchell, S. M. (2017). Conflict management in land, river, and maritime claims. Political Science Research and Methods, 5.Find this resource:

Owsiak, A. P. (2012). Signing up for peace: International boundary agreements, democracy, and militarized interstate conflict. International Studies Quarterly, 56(1), 51–66.Find this resource:

Potter, W. C. (1980). Issue area and foreign policy analysis. International Organization, 34, 405–427.Find this resource:

Prorok, A. K., & Huth, P. K. (2015). International law and the consolidation of peace following territorial changes. Journal of Politics, 77(1), 161–174.Find this resource:

Randle, R. F. (1987). Issues in the history of international relations. New York: Praeger.Find this resource:

Rosenau, J. N. (1966). Pre-theories and theories of foreign policy. In R. B. Farrell (Ed.), Approaches to comparative and international politics (pp. 27–93). Evanston, IL: Northwestern University Press.Find this resource:

Rosenau, J. N. (1967). Foreign policy as an issue-area. In J. R. Rosenau (Ed.), Domestic sources of foreign policy (pp. 11–50). New York: Free Press.Find this resource:

Schultz, K. A. (2014a). Borders, conflict, and trade. Annual Review of Political Science, 18, 125–145.Find this resource:

Schultz, K. A. (2014b). What’s in a claim? De jure versus de facto borders in interstate territorial disputes. Journal of Conflict Resolution, 58(6), 1059–1084.Find this resource:

Schultz, K. A. (2017). Mapping interstate territorial conflict: A new data set and applications. Journal of Conflict Resolution, 61, forthcoming.Find this resource:

Senese, P. D., & Vasquez, J. A. (2008). The steps to war: An empirical study. Princeton, NJ: Princeton University Press.Find this resource:

Shelef, N. G. (2016). Unequal ground: Homelands and conflict. International Organization, 70(1), 33–63.Find this resource:

Simmons, B. A. (2005). Rules over real estate: Trade, territorial conflict, and international borders as institution. Journal of Conflict Resolution, 49(6), 823–848.Find this resource:

Tir, J. (2006). Redrawing the map to promote peace. New York: Lexington Books.Find this resource:

Tir, J., & Ackerman, J. T. (2009). Politics of formalized river cooperation. Journal of Peace Research, 46(5), 623–640.Find this resource:

Tir, J., & Stinnett, D. M. (2011). The institutional design of riparian treaties: The role of river issues. Journal of Conflict Resolution, 55(4), 606–631.Find this resource:

Tir, J., & Stinnett, D. M. (2012). Weathering climate change: Can institutions mitigate international water conflict? Journal of Peace Research, 49(1), 211–225.Find this resource:

Toft, M. D. (2003). The geography of ethnic violence: Identity, interests, and the indivisibility of territory. Princeton, NJ: Princeton University Press.Find this resource:

Toft, M. D. (2014). Territory and war. Journal of Peace Research, 51(2), 185–198.Find this resource:

Vasquez, J. A. (1983). The tangibility of issues and global conflict: A test of Rosenau's issue area typology. Journal of Peace Research, 20(2), 179–192.Find this resource:

Vasquez, J. A. (1993). The war puzzle. Cambridge, U.K.: Cambridge University Press.Find this resource:

Vasquez, J. A., & Henehan, M. T. (2011). Territory, war, and peace. New York: Routledge.Find this resource:

Vasquez, J. A., & Mansbach, R. W. (1984). The role of issues in global co-operation and conflict. British Journal of Political Science, 14(4), 411–433.Find this resource:

Walter, B. F. (2006). Building reputation: Why governments fight some separatists but not others. American Journal of Political Science, 50(2), 313–330.Find this resource:

Wolf, A. T. (1998). Conflict and cooperation along international waterways. Water Policy, 1(2), 251–265.Find this resource:

Zacher, M. W. (2001). The territorial integrity norm: International boundaries and the use of force. International Organization, 55, 215–250.Find this resource:

Zawahri, N., & Mitchell, S. M. (2011). Fragmented governance of international rivers: Negotiating bilateral versus multilateral treaties. International Studies Quarterly, 55(3), 835–858.Find this resource:

Zimmerman, W. (1973). Issue area and foreign-policy process: A research note in search of a general theory. American Political Science Review, 6, 1204–1212.Find this resource: