distinguishing rivals that go to war from those that do not: a quantitative comparative case study...

Distinguishing Rivals That Go to War from Those That Do Not: A Quantitative ComparativeCase Study of the Two Paths to WarAuthor(s): John A. VasquezSource: International Studies Quarterly, Vol. 40, No. 4 (Dec., 1996), pp. 531-558Published by: Wiley on behalf of The International Studies AssociationStable URL: http://www.jstor.org/stable/2600890 .Accessed: 12/06/2014 16:17

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Wiley and The International Studies Association are collaborating with JSTOR to digitize, preserve and extendaccess to International Studies Quarterly.

http://www.jstor.org

This content downloaded from 91.229.248.152 on Thu, 12 Jun 2014 16:17:28 PMAll use subject to JSTOR Terms and Conditions

http://www.jstor.org/action/showPublisher?publisherCode=blackhttp://www.jstor.org/action/showPublisher?publisherCode=isahttp://www.jstor.org/stable/2600890?origin=JSTOR-pdfhttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsp

International Studies Quarterly (1996) 40, 531-558

Distinguishing Rivals That Go to War from Those That Do Not:

A Quantitative Comparative Case Study of the Two Paths to War

JOHN A. VASQUEZ

Vanderbilt University

Many interstate enduring rivalries experience wars, some do not. This analysis presents and tests an explanation of whether, why, and how rivals go to war. It is argued that rivalries between equal states that do not go to war are those in which territorial issues are not at stake. Rivalries in the absence of territorial issues tend to go to war only by being embroiled in an ongoing war by a third party. A series of tests with emphasis on rivalries between major states occurring during 1816-1986 supports the territorial explanation. Two distinct paths to war are empirically identified-one leading to a dyadic war involving a territorial dispute(s) and a second path by which rivals without a territorial dispute join an ongoing war because of contagion factors.

Enduring rivalries is a topic that has received increased attention in the last few years (see Wayman, 1983, 1996; Huth and Russett, 1991; Geller, 1993; Goertz and Diehl, 1993; Thompson, 1995; Bennett, 1996; Hensel, 1996). Most rivalries result in war, but a few do not. Is it possible to distinguish the few that do not go to war from the many that do? This article presents a theoretical answer to this query based on the territorial explanation of war and tests this explanation on rivalries between major states from 1816 to 1986. The theoretical analysis suggests that rivalries differ markedly in how they go to war, so much so that it is possible to distinguish two different paths to war. The identification of these paths provides a more complete understanding of why and how rivalries between equal states lead to war.

This article begins with a discussion of some of the conceptual issues involved in defining rivalry. It then develops a theoretical explanation of why and how rivalries go to war, presenting two propositions that can be tested empirically. The next section outlines the research design, and the fourth presents the findings.

Autthor's note: My thanks to Scott Bennett, Paul F. Diehl, Douglas M. Gibler, Marie T. Henehan, A. Bikash Roy, Tom Walker, and the reviewers and editors of ISQ for valuable comments. The final responsibility for the article remains mine alone, however.

C 1996 Inteirnational Studies Association. PuLblished by Blackwell Publishers, 238 Main Street, Cambridge, MA 02142, USA, and 108 Cowley Road, Oxford OX4 IJF, UK


http://www.jstor.org/page/info/about/policies/terms.jsp

532 Distinguishing Rivals

The Concept of Rivalry Commentators on international history, whether political scientists or historians, have often felt the need to use the term rivalry to characterize a special, competitive relationship that emerges between two parties that distinguishes it from the typical relationship that governs political actors. Thus, we have the Franco-German rivalry of the late nineteenth and early twentieth centuries, the rivalry between Prussia and Austria over Germany, and the recent Soviet-American rivalry. No one questions that these relationships deserve the label "rivalry," but what makes them conceptually distinct from other conflictive or competitive relationships one might find in history that are not usually considered rivalries?

Operational definitions of rivalry emphasize repeated disputes (i.e., the use or threat of force) as the major characteristic of rivalry. Goertz and Diehl (1993) review the various operational definitions currently in use and the effect different dispute thresholds have on the number of wars and rivalries included in a definition. While these operational definitions have been useful for analyzing data, they do not really provide a conceptualization of the dynamics of rivalry that give rise to the recurrent disputes in the first place. What is needed is a better, conceptual definition that will be able to predict the onset of disputes (see also Thompson, 1995:195-7).

Rivalry is defined here as: a relationship characterized by extreme competition, and usually psychologi cal hostility, in which the issue positions of contenders aregoverned primarily by their attitude toward each other rather than by the stakes at hand. Competition is the engine that drives the rivalry and, in political interactions (as opposed to purely commercial transactions), produces hostility at some level. As conflict recurs, contenders become more concerned with hurting or denying their competitor than with their own immediate value satisfaction, and with this, hostility deepens and goes beyond that associated with normal conflict. I

While competition and the hostility often associated with it are the most obvious characteristics of rivalry, the foundation on which rivalry rests lies with the issue(s) under contention (cf. Bennett, 1996). Technically, when issues are approached and defined in terms of what they mean for the other actor, this is called an actor dimension; as opposed to a stake dimension, which defines issues in terms of the intrinsic value the stake has to oneself (see Mansbach and Vasquez, 1981:60). The hallmark of a rivalry is the adoption of an actor dimension, which is driven by negative affect (i.e., hostility), rather than a stake dimension, which is driven by a cost-benefit analysis of the stake under contention. Normal conflict is guided ultimately by a selfish concern, whereas rivalry, because of the persistence of hostility, can get out of hand and make for disagreement and negative acts that from a strict cost-benefit analysis are not necessary. When an actor dimension is adopted, there is also a tendency for all issues (and the specific stakes that compose them) to become linked into one grand issue-us versus them.

Thus, as I have noted elsewhere (Vasquez, 1993:82): A rivalry is a competitive relationship among equals that links stakes into issues on the basis of an actor dimension. The actor dimension results fi-om a persistent disagreement and the use of negative acts which build up negative affect (psychological hostility). Hostility reinforces the actor dimension which gradually reduces all issues

I The level of hostility can be expected to var-y depending on how many rivalries a political actor is involved in and how it ranks rivals by the threats they pose. When there are multiple rivalries, there may be, as Deutsch and Singer (1964) argue, cross-cutting of certain issues which will moderate affect. Whereas when there is only one rivali-y cross-cutting is less likely, especially if all the issues are reduced to one of "us vs. them" or "good vs. evil" (see Mansbach and Vasquez, 1981 :ch. 7 for elaboration). Hence, political actors involved in only one rivalry, such as the U.S. and USSR from 1947 to 1964, will have a higher level of hostility and will be more guided by their mutual hostility than political actors involved in multiple rivalries, for example, the U.K.-Italy rivali-y prior to World War II.



JOHN A. VASQUEZ 533

to a single overarching issue. Simultaneously, concrete stakes are transformed into symbolic and transcendent ones, and proposals for the disposition of stakes and the resolution of an issue distribute costs and benefits on an unequal basis. This makes for more disagreement, greater use of negative acts, and an intensification of hostility, which in turn reinforces the actor dimension. An escalating conflict spiral results, which creates an atmosphere in which crises are likely to be born.

Rivalry becomes a way of life. The relationship is difficult to change because each side is involved in a vicious circle in which hostility makes actors define issues in ways that are intractable and threatening, and actors become hostile, in part, because of the way they have defined the issues that divide them.

Issues become intractable not simply because they are intrinsically difficult to resolve, but also because one side cannot just seize the stakes at hand through sheer force. Relative capability places the actors in a situation from which neither can make a decision without the agreement of the other. The result, typically, is stalemate, which fuels both hostility and recurring disputes. The advantage of such a conceptualization is that it gets at the dynamics underlying the "enduring disputation" (Wayman, 1983:18, note 6) of rivals and hence is able to predict when two political actors can be expected to engage in recurring disputes.

The inability of either side to impose its issue position leads me to assume, contrary to Wayman and Jones (1991) and Goertz and Diehl (1993), that relative equality is a prerequisite of rivalry. Without equality there cannot be a real competition, because one side would be capable of dominating the other. Another way of putting this is that interactions between equals are bound to be different from interactions between unequals, because the logic of equality of power or status is fundamentally different from the logic of inequality. This can be seen by looking at some of the major-minor dyads Wayman and Jones (1991) and Goertz and Diehl (1995) identify as rivals, such as Russia-Turkey (pre 1816-1918) and U.S.-Mexico (1896-1921) (Wayman and Jones, 1991) or U.S.- Haiti and India-Nepal (Goertz, 1994:221-2; Goertz and Diehl, 1995). The relationships and behavior of these dyads, I would submit, are fundamentally different from the Anglo-German rivalry, the Soviet-American rivalry, or the rivalry between France and Germany, Prussia and Austria, or Russia and Aus- tria-Hungary (cf. Thompson, 1995:197-200). Relations between unequals is better discussed based on an imperialist or asymmetric perspective than the perspective of rivalry.

From a psychological perspective, the relationship between relative equals should be different from that between unequals. In an unequal relationship, only the weak tend to take an actor dimension and are guided by extreme hostility (and a hostility based primarily on seething resentment rather than on the other aspects of hostility). Likewise, the strong have no need to fear their weaker opponent, and hence are more motivated by predation than security. The absence of mutual fear, insecurity, and hostility suggests that the fundamental psychological underpinnings of unequal relationships are different from those of equal relationships. Nevertheless, whether rivalries are better conceptualized by controlling for equality is a question that should be decided ultimately on the basis of empirical research rather than solely conceptual analysis. By examining only rivals between equals, this analysis provides a basis for a subsequent comparison with the behavior of protracted conflict between unequals.

This definition of rivalry, then, emphasizes three characteristics: First, the issue(s) which is the foundation of the rivalry. Second, the contention over this issue(s), which between equals gives rise to persistent disagreement in the form of an actor dimension. Third, psychological hostility, which arises naturally from persistent disagreement and is typical of the most enduring rivalries.




Within the empirical literature, rivalries have attracted interest because dyads that have recurrent disputes have a much higher probability of going to war than other dyads (see Diehl, 1985; Goertz and Diehl, 1992a; Wayman, 1996), with the possible exception of contiguous dyads (Bremer, 1992). No one has asked, however, what factors distinguish the many rivalries that go to war from the few that do not. This is an important question for both theoretical and methodological reasons. Theoretically, being able to explain the difference would add to our knowledge about the onset of war. Methodologically, the question provides a challenge and hence a test for appraising the explanatory power and empirical accuracy of various explanations of war.

Clearly, distinguishing interstate rivalries that go to war from those that do not is a task made immensely easier if one has an explanation of war in general. It is maintained here that the most important things about understanding whether rivalries result in war are: (1) the issues under contention-some issues, like territorial issues, are much more prone to war than others, for example, purely ideological issues; and (2) the pattern of interaction-that is, how the issues are handled.

From this perspective, the main difference between rivalries that have a war and those that do not is the ability to avoid crises involving territorial issues. Rival states that do not have territorial disputes with each other tend not to fight a major war with each other unless they are brought in by third parties. The next section elaborates the meaning of these propositions and provides a justification for them from the general theoretical explanation from which they are derived.

Explaining the Onset and Expansion of War

War is a very complex subject, in part because war does not result from a single set of causes. There are many paths to war. In another analysis (Vasquez, 1993), I have delineated the typical path by which relatively equal states have become embroiled in wars with one another in the modern state system. I had initially hoped that a single explanation of war over all of history could be constructed. Instead, I have come to the conclusion that there are different types of war and that each type can be preceded by different causal sequences. To explain war requires identifying the various paths that lead to war.

In trying to identify the causal sequences that precede wars, I have distinguished between underlying and proximate causes. Underlying causes are fundamental causes that set off a train of events (the proximate causes) that end in war. Of all the various issues over which wars can arise, I argue that territorial disputes between neighbors are the main source of conflict that can give rise to a sequence of actions that ends in war (see also Kocs, 1995). Since all neighbors usually must, at some point in their history, contend with this issue, and because this issue is an issue over which most neighbors are apt to fight, I see territorial disputes as an underlying cause of war. Whether or not they will give rise to war, however, will depend on how the issue is treated (the proximate causes). Since how states treat each other varies according to a number of characteristics, the proximate causes of war are much more varied than the underlying causes.

I identify proximate causes by looking at the foreign policy practices that lead to war. I argue that, in the modern global system, war is likely among equals if the practices of power politics are used to try to resolve territorial disputes. Power politics behavior, rather than preventing war, actually increases the probability that it will break out. This is because the main practices of power politics-alliances, military buildups, and the use of realpolitik tactics-increase insecurity and hostility, motivating each side to take a harder line. Coercion fails to produce compliance or compromise because the nature of the issue at stake is such that giving in (especially



JOHN A. VASQUEZ 535

to an equal) is unthinkable. Under such conditions, the use of power politics produces a set of interactions and domestic political environments that make war increasingly likely. Between equals, war is brought about by each side's taking a series of steps that increase hostility and make the issue at hand more intractable. This involves the disputants in a series of crises, one of which escalates to war. Evidence on which steps increase the probability of war and which characteristics of crises make them prone to escalation can be found in existing empirical research (see Vasquez, 1993:ch. 5).

The use of the foreign policy practices of power politics to handle certain territorial disputes, it is predicted, will increase the probability of war, but whether power politics will be used depends, in part, on the nature of the global political system in operation. The global institutional context, in particular, whether it provides norms and "rules of the game" for resolving issues, has a major impact on whether states will resort to power politics. Preventing war and creating peace involves learning how to build structures that provide mechanisms for resolving issues through diplomacy rather than armed force.

To summarize: In the modern state system, one of the main factors that bring about war between equals is the rise of territorial disputes, particularly between neighbors, that, in the absence or failure of a global institutional network to resolve the issue politically, make actors resort to the unilateral solutions provided by power politics.

From the above it follows that rivalries that involve territorial disputes are much more apt to result in war than rivalries that do not involve territorial disputes. Attempts to demark and define territory, especially borders, is an important source of rivalry. In fact, this territorial aspect is reflected in the very etymology of the term rival, which is derived from the Latin rivalis, which means "one using the same stream (rivus) as another" (American Heritage Dictionary, 2nd college ed.). Thus, in the first use of the term, rivals were those who both sought to use a life-sustaining piece of territory that often had to be shared.

In the modern global system, many neighbors ended up contending on territorial stakes, and one suspects that many rivalries originated in attempts to control the space between them. Hence, it should come as no surprise that most rivalries are between neighbors and appear related to territorial disputes. Less frequent are rivalries between noncontiguous states. Using the Wayman andJones (1991) sample, which identifies twenty-eight interstate rivalries between 1816 and 1986, it has been found that twenty-four of them were between neighbors, whereas only four were not (Vasquez, 1993:134-5).

One of the problems with testing the proposition that rivals involved in territorial disputes are more apt to go to war is that since war is multicausal, there will be rivals that go to war without having a territorial dispute. A valid test of the proposition will therefore have to incorporate this added complexity, but to do so requires identifying at least some of the additional conditions under which rivals go to war.

One of the major ways states without territorial disputes go to war is that they are drawn into a dyadic war that spreads to become multilateral; that is, a complex war (see Vasquez, 1993:71-4). Put another way, the rivals are brought into a war by third parties. Models of contagion and diffusion, then, become relevant for determining who will be at war and when. If having a rivalry focused on territorial questions is one path to war, a second path to war is for rivals without a territorial dispute to be drawn into a war. Furthermore, one would expect, on the basis of the above theoretical analysis, that this complex war would begin with a territorial dispute between the initial belligerents.

Existing empirical findings offer some clues as to the path by which interstate wars expand (see Bueno de Mesquita, 1978; Organski and Kugler, 1980; Yamamoto and Bremer, 1980; Wayman, 1984; Sabrosky, 1985; Siverson and Starr, 1991). Once




a war breaks out, other states are brought in because of alliance commitments or diffusion processes involving territorial contiguity (see Siverson and Starr, 1991), ongoing rivalries, the breakdown of political order, economic dependence, or simply the dynamic of the ongoing war itself (see Vasquez, 1993:ch. 7 for a full discussion).

Taken in conjunction with the first path to war, the following would be predicted:

1. The main factor that distinguishes rivals that go to war, at some point in their history, from those that do not is the presence of an ongoing territorial dispute. Territorial disputes make war more likely. Because there are other paths to war, this path would be expected to hold primarily for dyadic wars and initial belligerents in a multilateral war.

2. The main path by which rivals that do not have territorial disputes go to war is to be brought into an ongoing war by one of the initial belligerents. This means that rivals without territorial disputes are more likely to be involved in complex wars rather than dyadic wars with each other. In addition, it would be expected that there be some tendency for rivals drawn into a war to join that war after some decent interval following initial hostilities. The longer the interval, the easier it would be to justify the inference that it was the ongoing war and processes of diffusion that drew in the rivals or provided an incentive for these rivals to fight.

Nevertheless, the immediate entry of a rival into an ongoing war should not be taken as evidence against the second path to war. Alliances or commitments to defend a third party could bring in a state fairly soon, as in World War I and World War II, when a major state(s) comes to the aid of a minor state that is being pressured by one's rival. Russia did this with Serbia in 1914, and Britain and France did this for Poland in 1939.

This theoretical analysis clarifies some of the dynamics and complexities of why rivals go to war. Since there are two distinct paths to war, it is difficult for rivals that are equal to avoid war. Nevertheless, the presence of distinct paths helps explain why war is more probable in some rivalries than others. Thus, the analysis can explain why war was more probable between Germany and France-Russia in 1914 than between Germany and Britain. Also, unlike other hypotheses, it clearly specifies the process by which rivals will come to war and the type of war it will be (dyadic vs. complex).

Finally, the explanation suggests why some rivalries do not result in war and what the characteristics of these rivalries should be. From this perspective, the U.S. and USSR did not fight a direct (dyadic) war with each other because there was no territorial dispute between them. A complex war was avoided by each side's taking care to manage their rivalry so as to avoid the escalation and spread of wars in which they were a party.2

Theoretically, the analysis seems plausible and has a certain amount of explanatory power. What needs to be seen is whether it can pass systematic testing.

2 One of the r-easons the U.S. and USSR were so concerned about managing theii- rivalh-y and especially inter vention into ongoing wars was the danger of escalation to nuclear war (see Kahn, 1968). The absence of a territorial dispute between the U.S. and the USSR meant that the issues dividing the two, which were primarily ideological, were not worth r-isking all-out war. The implication of this analysis is that nuclear deterrence by itself did not prevent war, which means that in rivalries that have a salient territor-ial dispute, deterrence would have a much higher probability of failing (see Vasquez, 1991; see also Thompson, 1995:209).



JOHN A. VASQUEZ 537

Research Design Because the analysis delineates two distinct paths to war, it is important that hypotheses derived to test the explanation be properly specified. We can begin by asking, on the basis of the theoretical analysis, what distinguishes rivals that go to war from those that do not. First, it would be expected that rivalries that have never been at war would be those that do not have territorial disputes. Second, it would be expected that although some rivals that do not have territorial disputes would go to war, they would (1) be more apt to be involved in complex multilateral wars rather than dyadic wars, and they would (2) have more of a tendency than rivals involving territorial disputes to join an ongoing war rather than be involved at the beginning of the war. Based on this analysis, the following two general propositions are derived:

Proposition 1: Rivals that have territorial disputes are more apt to go to war directly with each other at some point in their history than those without territorial disputes. Hence, rivals that do not go to war should be those without territorial disputes.

Proposition 2: Rivals that go to war in the absence of territorial disputes should be involved in more multilateral wars than dyadic wars. Likewise, rivals that go to war in the absence of territorial disputes should be more likely to get involved in ongoing wars than at the beginning of wars.

Since the explanation from which these propositions are derived posits different paths to war depending on whether states are relatively equal or unequal, dyads consisting of unequal states (i.e., major-minor dyads) will not be examined. Even though wars of equality are thought to be governed by similar paths to war, especially in the presence of rivalry, there is some evidence to suggest that minor states behave differently from major states-sometimes more cautiously and at other times more aggressively (see Vasquez, 1993:127, 168, 191, 230-1, 316, 318, 339, note 17). For this reason, this analysis will be confined only to rivalries between major states. Such a procedure is not unusual in peace research (see Singer, Bremer, and Stuckey, 1972; Wayman, 1996). This also has the advantage of focusing on cases about which there is widespread historical knowledge. The standard Correlates of War list for major powers will be taken as an operational definition for distinguishing major from minor states.3

Any new theoretical approach requires that new data be collected, and this can slow down considerably the testing process. As a field, we are only beginning to get data on rivalries, and the efforts to date have produced disagreements on exactly what constitutes a rivalry conceptually and how it should be operationalized. It is no surprise that differences in definition should produce different lists of rivalries (see Goertz and Diehl, 1993). The differences in the lists are not as severe as one might suspect, however, since they center primarily on how many disputes to use as a threshold for determining what is or is not a "true" rivalry. An obvious solution to this definitional problem is to treat the amount of "enduring disputation" (Wayman, 1983:18, note 6) (i.e., the variation in the number of militarized disputes in a dyad) as an underlying dimension to measure the degree of rivalry. Goertz and Diehl (1995) move in this direction by establishing thresholds for sporadic or isolated conflict, proto-rivalries, and enduring rivalries (but see also Goertz and Diehl, 1994).

To date most quantitative analyses have employed the number of militarized interstate disputes (MIDs) as the basic indicator of an interstate rivalry (see Goertz

3 Major powers are identified by Small and Singer (1982:45) as: Austria-Hungar-y (1816-1918), Prussia (1816-1870) and its successor Germany (1871-1918, 1925-1945), Russia/USSR (1816-1917, 1922-present), France (1816-1940, 1945-present), England/U.K. (1816-present), Italy (1860-1943), Japan (1895-1945), U.S. (1898-present), and China (1 950-pr-esent).




and Diehl, 1993). This analysis will do the same; all three major lists of rivalries based on Correlates of War militarized interstate dispute (MID) data will be employed. These lists can be ordered by the degree to which their operational criteria reduce the potential set of interstate rivalries. This is accomplished by two sets of rules, one defining the number of disputes required and the second the length of time examined. The most restricted list is that of Wayman and Jones (1991:5), who operationally define an enduring rivalry as having at least five reciprocated militarized disputes during a twenty-five-year period, each of which must last for a minimum of thirty days. Rivalries end if there is no further reciprocated dispute over a twenty-five-year span. These criteria produce only seven dyadic rivalries between major states from 1816 to 1984. The main reason for this is that, unlike other operational definitions, Wayman and Jones's (1991) criteria require that a dispute be reciprocated in order to count as an indicator, whereas others look at the total number of disputes regardless of whether they are reciprocated. Wayman and Jones (1991) adopt this rule in part becauseJones (1988) shows that about 40 percent of the militarized disputes never receive a response from the target and because sometimes militarized disputes involving minor states cluster, making a dyad appear as an enduring rivalry when in fact it may not be.

The second most restrictive list is that of Goertz and Diehl's "enduring" rivalries which uses six militarized disputes within twenty years as a threshold. On the basis of an extensive analysis of disputes between a variety of states, Goertz and Diehl (1993:167) find a clear drop in the number of interstate rivalries if more than six disputes are used as a threshold. This operational definition results in eleven rivalries between major states from 1816 to 1976.

The least restrictive list is that of Wayman (1983, 1996) who identifies a rivalry existing between two major states if they have at least two militarized interstate disputes with each other over the course of a decade. A rivalry is said to end ten years after the last militarized dispute. One of the advantages of his approach is that it identifies more specific time periods when a dyad is a rivalry. This permits an examination of each period to see which path to war it follows. Such a specification helps alleviate the number-of-cases problem, which can be quite severe when identifying only rivals and not periods of rivalry. Wayman's (1996) criteria produce twenty-three rivals between major states and forty-four periods of rivalry.

It is assumed that as the number of militarized disputes increases, the kind of relationship depicted in the theoretical portion of the article is likely to exist; that is, it is assumed that the repetition of militarized confrontations is going to indicate a highly competitive relationship characterized by negative affect (hostility) and governed by an actor dimension.

Of course, the repetition of disputes does not directly tap hostility or the actor dimension, and no claim is made here that it does. Rather, the repeated MIDs are seen as an indirect indicator of these factors, which is not an implausible assumption, especially for the rivalries characterized by a large number of disputes. Whether the assumption is accurate is an empirical question that will need further research that is beyond the scope of this article.4 Suffice it to say here that the main purpose of this article is not to establish the empirical superiority of the particular conception of rivalry offered in the first section, but the superiority of the explanation of peace and war in which that conception of rivalry happens to be embedded. For such a test, it is better to use standard lists of rivalry, if it is assumed that these bear some

4 It is certainly the case that rivals characterized by the kind of hostility stipulated in the definition of rivalry employed here will have repeated MIDs. Hostility of this sort is posited as a sufficient condition for repeated confrontations. What is not clear is whether there exist dyads with repeated confrontations that lack hostility and are not governed by an actor dimension. The presence of the latter would make the use of the MID indicator more complicated.



JOHN A. VASQUEZ 539

reasonable correlation to the more complicated unmeasured aspects of the concept. The various rivalries that will be used in the data analysis are reported in Table 1 along with other relevant measures.

The real problem occurs in trying to find data on territorial disputes. Very little systematic work has been done on this question, although there are some data on territorial changes (Goertz and Diehl, 1992b) and lists of border conflicts (Day, 1987). One of the best analyses of the relationship between territorial issues and war is Holsti (1991), but his analysis is not based on precise operationalized measures. Eventually, data on territorial issues and disputes will need to be collected to test the propositions. In the present circumstances, territorial contiguity will be taken as an indirect measure. It is argued in Vasquez (1993) that at some point in their history, neighbors that are relatively equal will tend to establish their borders through the use of force. If this is the case, it can be expected that states that are contiguous and are rivals are in fact likely to be disputing over territorial issues. Of course, this will need to be checked historically in each case and documented extensively and/or coded in a scientifically reliable manner, but such a project would require a separate analysis.

For now, each case can be examined on the basis of a cursory historical review to see whether rivals are fighting over territorial issues. In this review, rivals will be considered as having a territorial dispute if: (1) they make direct claims to a piece of territory held or occupied by one of the rivals, or (2) they have competing claims regarding territory held by a third party. The small number of cases permits each to be checked to see whether it fits the logic of the hypothesis. The listing of the dyads in the contingency tables is thus an integral part of the data analysis and can be seen as a set of quantitative comparative case studies. Such a procedure is an efficient way of determining whether more rigorous, but time-consuming and costly, data collection is warranted.

Lastly, contiguity can serve as an indirect indicator, because from the theoretical perspective being presented here, it would be expected that if contiguous rivals did not experience war in the manner predicted, the explanation would be falsified. The use of contiguity therefore satisfies the condition of falsifiability.5

Employing the above operational indicators, the following hypotheses will be tested:

1. Rival dyads that are contiguous are more apt to go to war at some point in their history than rival dyads that are not contiguous.

2. Rivalries involving contiguous states are more apt to end in dyadic war than rivalries involving noncontiguous states (to be tested by removing cases of multilateral war).

3. Noncontiguous rivals that go to war are much more apt to be involved in multilateral wars than contiguous rivals that go to war.

4. Noncontiguous rivals that go to war are much more apt to join an ongoing war than contiguous dyads that go to war.

5. In comparison to contiguous rivals, noncontiguous rivals will either have no war or be involved only in multilateral wars with rivals.

Conversely, it is a limited indicator because it may not be acceptable to those who hold that contiguity may be associated with war not because territorial issues are more prone to violence, but because contiguity provides an opportunity for war due to proximity or frequent interactions. Theoretical refutations of these positionls are presented in Vasquez (1993:ch. 4). In order to resolve the debate over why neighbors fight-whether because of proximity, interactions, or territoriality-both sides of the debate must come up with a set of crucial tests (see Vasquez, 1995). The analysis in this article is not intended to provide such a test, but to assess a territorial explanation of why and how rivalries go to war, something that neither the proximity nor the interaction explanationi has attempted to do.




TABLE 1. Comparison of Major State Rivalry Dataa

Wayman Goertz Dyadicl Dyad Contig.b Wayman andJones and DiehlC WaTd Multi

FR-GER Y 1830-1842 1850-1880 1850-1945 Franco-Prussian M 1905-1933 1905-1939 WWI M 1936-1945 WWII M

FR-IT Y 1860-1876 1888-1903 1925-1950 WWII M

FR-RUS N 1830-1864 Crimean M 1917-1928 1948-1971

FR-AH N 1848-1869 Ital Unification M 1914-1918 WWI M

FR-JN N 1938-1950 No wars PRUS-AH Y 1865-1876 Seven Weeks M GER-RUS Y 1838-1860 [WWI, WWII]* RUS-AH Y 1912-1918 WWI M RUS/USSR-JN Y 1895-1913 1895-1945 1895-1976 Russo-Japanese D

1917-1930 1933-1955 Changkufeng D

Nomohan M WWII M

RUS/USSR-CH+ Y 1914-1939 1898-1986 1898-1929 Sino-Soviet D 1966-1984

UK-FR Y pre-1816-1840 Fr.Rev/Nap M 1825-1850 1888-1908

UK-RUS N 1849-1871 Crimean M 1877-1914 1877-1923 1917-1933 1946-1971

UK-GER N 1900-1931 1900-1939 WWI M 1938-1945 WWII M

UK-JN N 1932-1950 1932-1954 WWII M UK-IT N 1934-1950 1911-1940 WWII M IT-AH Y 1843-1887 1843-1918 1843-1915 Aust-Sardinian M

Ital Unification M Seven Weeks M

1904-1918 WWI M IT-GER N 1934-1945 [WWI]* IT-RUS N 1893-1905 [Crimean]*

1917-1928 1937-1951 WWII M

US-UK N 1837-1861 No wars 1902-1913

US-GER N 1915-1927 WWI M US-JN N 1932-1950 WWII US-USSR N 1917-1928 No wars

1946-1983 1946-1986 1946-1973 US-CH N 1900-1915 Boxer Rebellion M

1949-1984 1949-1974 1949-1974 Korean M

Number of cases: 23 dyads 7 dyads 11 dyads



JOHN A. VASQUEZ 541

TABLE 1. Continued

(a)Based on Wayman (1996), Wayman andJones (1991), and Goertz and Diehl (1995:Table 1). (b) Contiguity (Y = yes, N = no) is operationally defined as an adjacent land border or a separation

of less than 150 miles of water. Data derived from Palmer (1961) and Langer (1972). Under this standard Correlates of War project operational definition the US-USSR is contiguous after 1959 when Alaska is granted statehood. However, in this analysis because both the U.S. and the USSR are continental nations that are proximate only in areas distant from population centers they are treated as not contiguous for the entire period.

(c) Goertz and Diehl omit 12 rival dyads of Wayman: FR-IT, PRUS-AH, RUS-AH, UK-FR, GER-RUS, FR-RUS, FR-JN, IT-GER, IT-RUS, FR-AH, US-JN, US-GER. Last dispute date is used, not termination date.

(d) War data including participants and date of entry are taken from Small and Singer (1982:Table 4.2). The 1917 allied intervention is not treated as an interstate war by Small and Singer (1982:80, 202, 227), but listed as an extra systemic and international civilwar. This is consistentwith Gaddis' (1987:4-5, 223) interpretation that the U.S. and USSR have never fought a war.

(*) Wars fought outside rivalry period. (?) Because USSR-China have a rivalry when both are major states, 1966-1984, the earlier rivalry of

1914-1939 is retained in the sample even though China was not then a major state. Conversely, the "rivalry" of Japan and China, 1914-1947, which produces three wars, is not included because there was never a period of rivalry when both were major states.

The final measurement problem that needs to be discussed before testing these hypotheses is how to operationalize "war at some point in their history." The various periods of rivalry identified make this problematic because sometimes wars occur before or after a particular period of rivalry. The general rule adopted is to include a war as occurring at some point in the rivalry's history if it occurred during or after a period of rivalry, but not if it occurred before. Since most wars occurred during a rivalry period, this is not a major problem; however, some specific cases were affected. Thus, for Goertz and Diehl, who identify the U.K.-Russia rivalry as 1877-1923, the earlier Crimean War is not included, although it is included in the Wayman sample, which identified the 1849-1871 period as one of rivalry. Similarly, in the Italy-Germany rivalry, which is identified as a rivalry by Wayman for 1934-1945, World War I where Italy and Germany were on opposite sides is not included because it occurred before the period of rivalry. Lastly, the U.K.-France rivalry is identified correctly by Wayman and Jones as predating 1816, whereas Wayman has two specific periods of rivalry (1825-1850 and 1888-1908). Since most observers would regard the U.K.-France rivalry as one that went to war, the French Revolutionary/Napoleonic Wars are included in the analysis, with England seen as a joiner.

Findings

Before beginning a report on the tests of these hypotheses, a brief review of the differences among the three lists of rivalries as reported in Table 1 is in order. Using a high threshold for determining rivalry, Wayman and Jones (1991) identify seven rivals and Goertz and Diehl (1995) identify eleven rivals. Basically, Goertz and Diehl, who do not require reciprocation to include an MID, identify all the rivals Wayman and Jones identify with one exception-U.K.-France (pre 1816-1840). The latter is a legacy of the earlier century, where there would be no question historically of its status as a major rivalry. In addition to the six rivalries Wayman and Jones (1991) also identify, Goertz and Diehl include: U.K.-Russia, U.K.-U.S., U.K.-Germany, U.K.-Italy, and U.K.-Japan. The change in operational criteria brings in five




rivalries involving the U.K. All these cases are important historically; theoretically they are of interest because they involve noncontiguous states and a leading (and often the leading) naval power.

These differences are not as major as those between the two restricted lists (Wayman and Jones (1991) and Goertz and Diehl (1995)) on the one hand and the broader list of Wayman (1983, 1996), which includes any two states that have two MIDs within ten years. The former have considerably fewer cases than the latter (7 and 11 vs. 23), as would be expected given their operational criteria. Two important questions are raised by this difference: (1) Are the rivalries included by Wayman's broader inclusion criteria really "rivalries"? (2) Will the sample affect the findings?

With one exception, Wayman includes all the periods of rivalry that Goertz and Diehl include-the latter identify 1837-1861 as a period of rivalry between the U.K. and the U.S. whereas Wayman identifies only 1902-1913 as a period of rivalry. Both, however, include the dyad.

Of more significance is what Wayman includes and Goertz and Diehl's definition leaves out. Goertz and Diehl's criteria omit twelve of Wayman's rival dyads (see Table 1, note c). Historically, almost all of these twelve omitted dyads are typically thought of as "rivalries," and some are of major historical importance; for example, for the World War I period, Goertz and Diehl's criteria omit: RUS-AH (which starts the whole thing off), FR-AH, and US-GER. For the World War II period, FR-IT, FR-JN, and US-JN are omitted. Also not included are the inter-war period rivalries of IT-GER and IT-RUS. In the nineteenth century, the most significant rivalry missing is that of PRUSSIA-AUS- TRIA, as well as FR-RUS and the previously mentioned U.K.-France.

On the positive side, Goertz and Diehl's definition eliminates a number of rivalry periods that never go to war. Goertz and Diehl's definition also does not see the more subtle (or marginal) rivalries of FR-RUS (twentieth century) and USSR-CH (in the Cold War) as true "rivalries." Given these outcomes, which are known only after the fact, the more restrictive criteria appear to be identifying those rivals that are more intense and for whatever reason are not able to avoid repeated confrontations and war. Since it is known that repeated confrontations are associated with the onset of war (Wallensteen, 1981; Leng, 1983), comparisons of results using the two different samples may allow inferences about the effect of the number of repeated confrontations and presumably the intensity of the rivalry (and its underlying hostility) to be made. If this last assumption is granted, the more restricted sample of Goertz and Diehl may be considered a set of rivalries where hostility is higher, although any inferences made on this basis must be considered only suggestive because there is no direct measure of hostility being employed. The real question, of course, is whether the high and low operational thresholds make any difference in the statistical analysis.

HYPOTHESES 1 & 2. Rivalries prone to war

Table 2 provides a preliminary look at all three lists of rivalries to get a sense of how they might differ in their impact on Hypothesis 1. Hypothesis 1 predicts that contiguous states are more apt to go to war than noncontiguous states. This hypothesis is fine as a preliminary test, but it must be remembered that it ignores the two paths to war, particularly the second which is intended to describe how noncontiguous states come to war. Keeping this caveat in mind, it is clear that Hypothesis 1 is supported in all three samples with respective Yule's Q's of .67, .50, and .57 (and Phi's of .65, .46, and .37), although these do not always reach the .05 level of statistical significance.6

5 The Yule's Q's and Phi's should be seen as heuristic devices to aid interpretation. What is important is not the specific value of the statistic, but how it changes from the early tables to the later as controls are added. Yule's Q and Phi are appropriate for 2X2 tables using nominal data. Yule's Q is simply gamma calculated for a 2X2 table. Phi is



JOHN A. VASQUEZ 543

TABLE 2. Rivals and War

a. Wayman andJones (1991) (5 MID threshold) Sample

No War Some War

US-USSR US-CH Noncontiguous

1 1

0 5 UK-FR

Contiguous FR-GER IT-AH RUS/USSR-JN RUS/USSR-CH

Likelihood ratio, p = .08a Corrected Yule's Q = .67b

Phi=.65 p=.O9

b. Goertz and Diehl (1995) (6 MID threshold) Sample

No War Some War

US-USSR US-CH Noncontiguous US-UK UK-IT

UK-RUS+ UK-GER UK-JN

3 4

O 4

FR-GER Contiguous IT-AH

RUS/USSR-JN RUS/USSR-CH


Phi=.46 p=.12




TABLE 2. Continued

c. Wayman 1996 (2 MID threshold) Sample

No War Some War

US-CH UK-IT FR-RUS

Noncontiguous US-RUS UK-GER IT-RUS/USSR US-UK UK-JN US-JN FR-JN UK-RUS US-GER IT-GER+ FR-AH

4 10

0 9

FR-GER RUS-AH Contiguous FR-IT RUS/USSR-JN

GER-AH RUS/USSR-CH IT-AH UK-FR GER-RUS...


Phi=.37 p=.08

(a) Chi-square probability. (b) Since Yule's Q always mathematically produces a perfect relationship when there is a zero in just

one cell, it can be corrected by placing a 1 in that cell (for discussion of the procedure used to correct Yule's Q, see Vasquez and Henehan (1992:411-4)). In all instances that this was done, the 1 worked against the hypothesis.

(*) See notes b and d in Table 1. (+) UK-RUS fought in the earlier Crimean War with England, joining the war on March 31, 1854.

This war is prior to Goertz and Diehl's rivalry period of 1877-1923 and so is not included according to the operational rules. Wayman (2 MID), however, has a UK-RUS rivalry period 1849-1871 so the war is included in part c of Table 2.

(+ +) IT-GER fought earlier in World War I with Italy joining the war on April 23, 1915. Since this war is prior to Wayman's period of rivalry of 1934-1945, it is not included.

(+ + +) Note the GER-RUS dyad is the only one in which a war is fought after the rivalry period. GER-RUS fight each other in both World War I and World War II, but Wayman lists a rivalry for only 1838-1860. According to the operational rules, all wars fought after a rivalry period are included in the analysis.

These positive associations mean that contiguous rivals are more frequently apt to have some war in their history than are noncontiguous rivals. Another way of saying this is that noncontiguous rivals are more likely to avoid war altogether than are contiguous rivals. What is also evident in the tables, when the Phi scores are the focus of examination, is that the more restrictive lists of Wayman and Jones (1991)

based on chi-square divided by the sample size. It tends to be lower than Yule's Q when dealing with small samples, hence it is less appropriate here, except when Q needs to be corrected. Yule's Q has the disadvantage of being vei-y sensitive to zeros and must be corrected when a zero appears in one cell (see note b to Table 2). Significance levels are reported for each table as well as for individual Phi scores. A discussion of these statistics can be found in Norusis (1993:210, 217).



JOHN A. VASQUEZ 545

and of Goertz and Diehl (1995) (5-6 MID threshold, respectively) do better than the broader (2 MID threshold) sample of Wayman (1996). This pattern, which will become more pronounced and consistent in later tables, implies that the more disputatious rivals better fit the explanation of war being tested in this analysis.

An examination of the contiguous cases that go to war (in Table 2, a and b)-France-GER, Italy-AH, RUS\USSR-Japan, and RUS/USSR-China)-seems to support the notion that rivals that are contiguous are actually fighting over territorial issues. All of these dyads have had rather serious territorial disputes in the wars they have fought, as will be discussed below. The only exception to this is the UK-FR case, where no direct territorial dispute between these two parties gave rise to the French Revolutionary Wars, which England joined only later.7

In the Wayman and Jones (1991) sample (Table 2, a), there are only two rivalries involving noncontiguous states, and these split, thereby weakening the association, but each case does provide support for the larger theoretical analysis. The U.S.-So- viet case, of course, is very intriguing if one does not accept, as I and several others do not, the conventional explanation that the Cold War did not become hot because of nuclear deterrence (see Kugler, 1984; Mueller, 1989; Vasquez, 1991). It is consistent with Proposition 2 and implies that in the absence of territorial disputes, rivals may be able to avoid war. The U.S.-China rivalry, although an exception, adds support to this notion, because the only war for the rivalry period (1949-1974) Wayman and Jones (1991) identify is the Korean War, which is a war neither the U.S. nor China really wanted. China was drawn in because the battlefield got too close to its border, and the U.S. miscalculated somewhat and got carried away with its military success adding territorial objectives it did not have initially (see George and Smoke, 1974). To this was added the problem that MacArthur apparently had even more territorial objectives than Truman. To the extent that China took MacArthur and other American hard-liners seriously, then the U.S. and China had a perceived territorial dispute, making this rivalry more dangerous. All in all, however, the U.S., despite MacArthur, did not place any direct claims on Chinese territory, so the Korean War is a better illustration of how an ongoing war draws in noncontiguous rivals.

The slightly broader Goertz and Diehl sample (Table 2, b) strengthens these findings by adding two more instances of noncontiguous states that do not fight, but they also add three noncontiguous rivalries involving the U.K. that do have some war, thereby slightly lowering the overall strength of association.

7 An examination of the minor-minor rivals in the Wayman and Jones (1991) sample also supports the conclusion that contiguous rivals are much more likely to have war-s over territor-y than noncontiguous states:

No War War-

Noncontiguous 0 1

Contiguous 4 9

No noncontiguous minor-minor rivals, with the exception of US-Spain (I1850-1898), ar-e identified by Wayman and Jones (1991) (and this is not really an exception because in 1898 it is really a major-minor dyad). Of the thirteen minor-minor contiguous rivals, nine have some war and four do not. A perusal of the nine cases that go to war (GRK-TUR, IND-PAK, ISR-EGY, ISR-SYR, N.KOR-S.KOR, BOL-CHILE, BOL-PARA, PERU-CHILE, IRAN-IRAQ) suggests that most are in fact wars over territory, the possible exception being Ir-an-Iraq (see Levy and Froelich, 1985), and even that has important territorial aspects (see the relevant discussion in Langer-, 1972:131 1). Of equal interest in terms of future research are the four rivalries involving contiguous states that do not go to war (CHILE-ARG, ECUD-PERU, AFG-PAK, THAI-CAM). These are not necessarily anomalies since the territorial explanation does not claim that war is inevitable even if terr-itol-y is at stake; the key is how the issues ar-e handled. These cases are of inter-est in ter-ms of finding out exactly why they did not go to war.




Table 2, c turns to Wayman's (1996) larger list of rivalries based on a ten-year rather than twenty-five-year duration. Here the relationship is statistically significant with a solid Yule's Q of .57, but a weaker Phi of .37. Nevertheless, the contiguous rivals fit perfectly.8 An inspection of the nine contiguous cases shows that almost all have territorial disputes that lead to war.

These territorial disputes are of two distinct types: claims to territory held by either one of the rivals or claims involving territory held by a third party. The rivalry of France-Germany is a notorious example of the first type. Italy and Austria, of course, are fighting over Italian irredenta. France and Italy have competing territorial claims going back to the Italian Wars begun in 1495, and similar territorial issues still play a role in the Italian Wars of Unification. Territorial claims against France are later resurrected by Mussolini. Germany and Russia have a long-standing territorial rivalry in the area of Poland and the Baltic states, which becomes greatly aggravated by German ambitions (beginning during World War I and greatly extended in Hitler's Lebensraum plan) to create a Mitteleuropa incorporating much of the Ukraine (see Bell, 1986:260, 284-5, 288; Kaiser, 1990:370-4, 377-84). It is the latter objective that makes the 1941 attack fundamentally territorial (see Vasquez, 1996a). Russia-Austria/Hungary become entangled over controlling territory from the declining Ottoman Em- pire. The nature of their territorial claims on the Ottoman Empire, however, were such that the rivals probably could have avoided war, if it were not for the presence of other Slavic states that made territorial claims that Austria-Hungary found threatening. The rivalry of Prussia-Austria begins as struggle for hegem- ony in Germany, but moves to warfare over specific pieces of land and eventually ends with the territorial unification of Germany under Prussia without Austrian influence (see Carr, 1991). Finally, Russia and Japan, and Russia and China, skirmish over borders and territory in the Far East (see Carr, 1985:56-7, 65). This suggests that at the heart of these rivalries and the reasons they end up in war are territorial disputes.

The ten cases of noncontiguous rivalries going to war in Table 2, c (northeast cell) depress the statistical association. A comparison of the three samples in Table 2, especially between the two restrictive samples and the broader Wayman sample, suggests that reducing the threshold for identifying rivalry will include more "deviant" noncontiguous cases that have some war, but will not include any "deviant" cases of contiguous rivals without war. The "deviant" noncontiguous states with some war, however, do not undercut the territorial explanation of war, if there exists a separate path that brings these states into war.

Tables 3-7 attempt to assess this more complicated explanation by introducing various controls incrementally. This provides a way of testing to what extent the cases in the northeast cell are being brought to war by a different process. Since the restricted samples both produce similar results in Table 2, the remaining analyses

8 Unlike Wayman and Jones (1991), which has the UK-FR as a r-ivalr-y pr-edating 1816 and is used to identify this rivalry as having some war, the Wayman (1996) sample has two per-iods of rivalry, the first of which, 1825-1850, can be seen as a legacy from the Napoleonic Wa-s and thus is legitimately included in the some-war cell. The second period, 1888-1902, however, is more truly an exception and for that reason is of theoretical interest. This case suggests that colonial territorial disputes are simply not as war-prone as other territorial disputes (a finding consistent with Most and Starr (1980)). From this analysis one might derive the following propositions: Rivals disputing with each other over respective core territol-y are more apt to go to war than rivals disputing over peripheral (including colonial) territory. Fi-om this it further follows that: Rivals fighting over core territol-y are apt to fight more intensely than r-ivals fighting over- peripheral territory.



JOHN A. VASQUEZ 547

will compare only the Goertz and Diehl (6 MID threshold) sample with the Wayman (2 MID threshold).9

Table 3 begins this assessment of the two-paths-to-war explanation by removing the cases of multilateral war. It provides a test of Hypothesis 2, which predicts that rivalries of contiguous states are much more apt to end in dyadic war than rivalries involving noncontiguous states. The results of this test are quite stark; it turns out that all the cases of noncontiguous rivals going to war (in Table 2, b and c) are multilateral wars. For both samples the relationship is perfect. For each of the samples, the respective Yule's Q's both go up to 1.00 as do the Phi's (see Table 3, a and b). Just how much weight can be placed on this finding is the focus of the remaining three hypotheses, which are crucial for assessing the accuracy of a territorial explanation of why and how rivals go to war.

For now, it is clear that the bivariate tests on major-major rivalries produce a solid association (Table 2), and closer inspection supports the claim that contiguous rivals are fighting over territory. Furthermore, the claim that noncontiguous rivals are brought to war by a separate path is confirmed further by the dramatic results in Table 3. Both the tests and examination of specific cases provide evidence consistent with Proposition 1, which maintains that rivalries that have territorial disputes are more prone to direct wars than rivalries that are not focused on territorial disagreements.

HYPOTHESES 3-5. The two paths to war

Hypotheses 3-5 assume that some states go to war because they have serious grievances with one another that they expect to be settled only by war and that there are other states that go to war but either do not want to or are embroiled in a war started because of someone else's rivalry. Another way of looking at these two paths to war is to distinguish between going to war because of a direct bilateral dispute and going to war as a result of supporting a third party. The different causal sequences associated with the onset of war on the one hand, and the spreading of war on the other, need to be better incorporated into how we conceive of our hypotheses and construct our research designs.

There are basically two ways of testing the claim that certain states are more prone to being brought into a war, rather than being in a rivalry where one party initiates war. The first is to see whether noncontiguous states are more likely to be involved in multilateral than in dyadic wars. Hypothesis 3 tests this claim. The second is to see whether noncontiguous rivals are more apt to be war joiners in an ongoing war. Hypothesis 4 tests this claim. This hypothesis provides a purer test of the notion that noncontiguous rivals are less prone to war and must be brought into an ongoing war started for other purposes. Unlike participation in multilateral wars where several parties might share the same grievances, participation in a war after a decent interval suggests that states are brought to the war for reasons different from those of the initial belligerents and most likely by a different process. Both these tests are premised on the assumption that different kinds of rivalries are prone to different types of war.

Table 4 presents a test of Hypothesis 3 by predicting that if the territorial explanation of war is correct, then noncontiguous rivals should fight primarily multilateral wars and not dyadic wars; whereas contiguous rivals could fight either. While the bivariate format does not provide the most precise test, it should produce

9 The Goertz and Diehl sample is the source of many analyses on rivalry; therefore, if only one restricted list is selected, this one should be it. It also has the advantage of having four more cases than Wayman andJones and dropping a case which, because it involves censored data (pre-1816), is pi-one to miscoding on the dependent variable. As can be seen in Table 2, the Goertz-Diehl sample is not being picked because it will do better than the Waynmatn anid Jones sample.




TABLE 3. Rivals and Any Dyadic War (Multilateral Wars Removed)

a. Goertz and Dieehl (1995) (6 MID thlreshlold) Sample

No War Any Dyadic War

Noncontiguous US-USSR US-UK

2 0

0 2

Contiguous RUS/USSR-JN RUS/USSR-CH

Likelihood ratio, p = .01 8a Yule's Q = 1.00

Phi = 1.00 p = .045

b. Wayman (1996) (2 MID threshold) Sample

No War Any Dyadic War

Noncontiguous US-USSR US-UK FR-JN IT-GER+

4 0

0 2

Contiguous RUS/USSR-J N RUS/USSR-CH

Likelihood ratio, p = .006a Yule's Q = 1.00

Phi= 1.00 p=.Ol

(a) See Table 2. (+ +) See Table 2.

some association if the hypothesis is accurate.'0 A fairly stringent test is to predict that any noncontiguous rivalry that has at least one dyadic war in the post-Napoleonic period (1816-1980) would be taken as a case falsifying the hypothesis. This means that only

I() This test underestimates the strength of the proposition because it coun-ts contiguous dyads havinig dyadic wars in favor of the hypothesis, but counts contiguous dyads having only multilater al wars as evidence against the hypothesis, when in fact the territorial explanation does not deny the latter possibility.



JOHN A. VASQUEZ 549

TABLE 4. Contiguity and Large Wars

a. Goertz and Diehl (6 MID threshold) Samplle

At Least One Only Dyadic War Multilateral Wars

Noncontiguous UK-GER UK-JN UK-IT US-CH

0 4

2 2

RUS/USSR-CH FR-GER RUS/USSR-JN IT-AH

Contiguous

Likelihood ratio, p = .06a Corrected Yule's Q = -.60

Phi=-.58 p=.10


At Least One Only Dyadic War Multilateral Wars

UK-GER FR-RUS UK-IT IT-RUS

Noncontiguous UK-RUS US-CH UK-JN US-JN FR-AH US-GER

0 10

2 7

RUS/USSR-CH FR-GER PRUS-AH RUS/USSR-JN IT-FR RUS-AH

Contiguous IT-AH GER-RUS... UK-FR

Likelihood ratio, p = .07a Corrected Yule's Q = -.48b

Phi=-.36 p =.12




TABLE 4. Continued

(*) The Wayman (2 MID) sample has 23 cases; the 4 not included here have no wars for the relevant periods (FR-JPN, US-UK, US-USSR, UK-FR). Three "no wars" are excluded in the Goertz and Diehl sample.

(a)See Table 2. (b) See Table 2. (++ + ) See Table 2.

noncontiguous rivals that fight exclusively multilateral wars will be taken as evidence in favor of the proposition. The results in Table 4 bear out this prediction. Not a single noncontiguous rivalry (in either sample) fought each other directly and exclusively by fighting a dyadic war. While the contiguous dyads reflect a similar tendency, it is less pronounced. The relationship is not quite statistically significant, but the corrected Yule's Q's are fairly impressive: -.60 and a moderate -.48 (the Phi's are -.58 and -.36).11 Just how many exceptions the contiguous rivals truly embody can be assessed by determining whether the multilateral war was an outcome of a rivalry driven by a territorial dispute or some other rivalry.

Hypothesis 4 provides one way of getting at that question. It recognizes the fact that in a multilateral war, those states that are involved from the beginning are different from those who join later on. This second group comes to the war because of contagion factors or because the war diffuses. This is a distinct path to war that can be differentiated from the factors that brought about the initial onset of war. Table 5 tries to get at this path by comparing those rivals that are present at the beginning of the war with those that join in.

Hypothesis 4 predicts that noncontiguous rivals are much more apt than contiguous rivals tojoin an ongoing war. This is a better test of Proposition 2, because unlike Hypothesis 3 it makes a clear distinction between the behavior of noncontiguous and contiguous rivals. To be a warjoiner, an actor must enter the war by declaration or troop commitment at least three months after the initial declaration. Dates of entry are given in Table 5.

To test this hypothesis, specific periods of rivalry and wars had to be examined. Wayman's (1995) shorter periods lend themselves better to such a test, and the results of this sample are reported in Table 5. One of the problems with shorter periods, however, is that they could potentially bias the test if one or two rivals had many short periods of rivalry and dominated the data. This, however, is not the case as can be seen from the table.

The results in Table 5 are consistent with the hypothesis, showing a statistically significant relationship at the .058 level with a Yule's Q of -.61, but a weaker Phi of -.34. Thus, as contiguity goes up (i.e., from noncontiguous to contiguous), the tendency to join an ongoing war goes down. Only five of eighteen contiguous rivalries go to war by joining an already ongoing war. Conversely, eight of thirteen noncontiguous rivalries go to war by joining an ongoing war. Five cases go to war from the beginning, but these are all multilateral wars. Of the five cases, two are authentic examples of noncontiguous rivalries that go to war, even in the absence of direct territorial disputes. The UK-GER rivalry in 1939 and to a lesser extent the FR-AH rivalry in 1859 are of this ilk. The other three cases, however, may reflect measurement error in that at least one sidejoined an ongoing war, albeit fairly early.

I I The negative sign in this and subsequent tables simply reflects the order of the variables in the contingency table and is not substantively relevant to the hypothesis. The negative sign means that as contiguity goes up (i.e., from noncontiguous to contiguLous), fighting in only multilater al wars goes down.



JOHN A. VASQUEZ 551

TABLE 5. Contiguity and Diffusion of Wars

Wayman (1996) (2 MID threshold) Sample (based on periods and war pairs)

Fought from War Joiner in Beginning an Ongoing War

UK-GER 1914 UK-IT 1940 a UK-GER 1939 UK-RUS 1854 b

Noncontiguous FR-AH 1859 UK-JN 1941 c FR-AH 1914 FR-RUS 1854b US-CH 1900 IT-RUS/USSR 1941c

US-JN 1941 c US-GER 1917 US-CH 1950 d

5 8

13 5

FR-GER 1870 FR-GER 1914 FR-GER 1939 FR-IT 1940 a PRUS-AH 1866 RUS/USSR-JN 1945'C

Contiguous IT-AH 1849 IT-AH 1915 f IT-AH 1859 GER-RUS/USSR 1941 IT-AH 1866 UK-FR 1793 g RUS-AH 1914 RUS-JN 1904 RUS/USSR-JN 1938 RUS/USSR-JN 1939 RUS/USSR-CH 1929 GER-RUS 1914

Likelihood ratio, p = .058+ Yule's Q = -.61

Phi=-.34 p=.06

(a) Italy declared war on FR and UK 6/10/1940; WWII started on 9/1/1939. (b) The Crimean War started on 10/23/1853; FR and UK entered 3/31/1854. (c) In WWII GER and IT attacked USSR on 6/22/1941; Japan attacked US and UK on 12/7/1941;

WWII started 9/1/1939. (d) China intervened against the U.S. in the Korean War on 10/27/1950, about 4 months after the war

began on 6/24/1950. This is the shortest time span in this column. (e) The USSR declared war on Japan and attacked Japanese forces in Manchuria on 8/8/1945. (f) Italy entered WWI on 5/23/1915; WWI began 7/29/1914. (g) The French Revolutionary Wars began on April 20, 1792 and France declared war on England on

Feb. 1, 1793. (+) See note a to Table 2.

For example, the FR-AH rivalry preceding 1914 really only came to war because of entangling alliances. A strong historical argument can also be made that the Anglo-German rivalry preceding World War I did not produce the war, that Germany wanted to avoid war with the U.K., and that the U.K. was dragged in because of Belgium (see Vasquez, 1993:95-6). Finally, the US-CH case reflects U.S.




intervention in the Boxer Rebellion, an intervention which it is inconceivable that the U.S. would have undertaken on its own. The rather solid Yule's Q, then, probably is underestimating the relationship.

The cases in the warjoiner (northeast) cell of Table 5 are all fairly standard. They all involve states that are brought into an ongoing war after it started. The Second World War in the Pacific is treated as an extension of the European war, but even if one objects to this interpretation, the U.K. and U.S. can still be seen as being brought into an ongoing Sino-Japanese war because their policies conflict with Japanese objectives in China and the region (Iriye, 1987:118, 148, 150, 156, 162, 171; see also Vasquez (1996b) for more detail).

Table 6 tests Hypothesis 4 in the Goertz and Diehl sample. The longer time periods in the Goertz and Diehl sample mean that multiple wars often occur in the same time period. Rather than drop this sample, it was decided to code a dyad based on the typical (modal) way it entered wars (from the beginning or later). Only three of the eight cases were subject to this rule (IT-AH, RUS-JN, and US-CH-see Table 1 for the wars), and IT-AH and RUS-JN were easily classified on the basis of the modal rule.12 For cases that lacked a modal path, a second rule was followed: the war within or closest to the period of rivalry identified by Goertz and Diehl was taken as the basis of the coding. Only the US-CH case was determined by this rule. 13 On the basis of these rules, the dyads in the Goertz and Diehl sample were classified into the categories presented in Table 6. The results are similar to those in Table 5, but considerably stronger. The corrected Yule's Q is -.85 and Phi is -.77; as states become more contiguous, the tendency to join wars (as opposed to fighting from the beginning) goes down dramatically.

This is an interesting increase in the Q and Phi, given the reduction in the number of cases. It is also a serendipitous finding in that it was brought about because of a discrepancy in the way the two samples measure duration of rivalry. A comparison of the two samples permits an examination of the typical path a rivalry traverses on its way to war (without the noise of atypical cases). Table 6 provides strong evidence that the typical path to war for noncontiguous rivals is to enter an ongoing war, while the typical path to war for contiguous rivals is to fight from the beginning. Identifying the typical path to war a rivalry follows makes the relationship depicted in Hypothesis 4 much clearer.

The final table combines the effects of the two paths to war to test Proposition 2. Table 7 tests Hypothesis 5, which predicts that either noncontiguous rivals will not go to war or if they go to war they will do so by participating in multilateral wars. Contiguous rivals are expected to be much more likely than noncontiguous rivals to fight dyadic wars. As can be seen in Table 7, the results are statistically significant in the predicted direction for both samples, with respective (corrected) Yule's Q's

12 IT-AH fought in the beginning in 1849, 1859, and 1866, and only once entered war as ajoiner (in 1915). Of these wars, the former all relate to the Italian Wars of Unification, and these seem to capture better the major reasons for the IT-AH rivalry. RUS-JN fought from the beginning in 1904, 1938 (Changkufeng), and 1939 (Nomohan), and entered as a joiner dyad in Wor-ld War II in 1945. Again, the former wars seem more critical for the purposes of the dyadic rivalry.

3I' The U.S. and China, as can be seen in Table 5, fough-t two wars in the post-Napoleonic period-the Boxer Rebellion and the Korean War. While both fall within Wayman's periods, Goertz and Diehl identify only 1949-1974 as a period of rivalry, so the Korean War is used as a basis of the coding. China is seen as inter-vening in an ongoing war.

In case this rule was not sufficient, a third r-ule was developed (but never used): a dyad would be classified as ajoiner if it seemed to have inter-vened in an ongoing war being fought by two other parties (regardless of the time of entry) or to have fought from the beginning, if it was one of the main participants briinging about the war. Under this rule, both the Boxer Rebellion (for the U.S.) and Korea (for Chinese inter-vention) would be classified in the joiner cell.



JOHN A. VASQUEZ 553

TABLE 6. Contiguity and Diffusion of Wars

Goertz anid Diehl (1995) (6 MID threshold) Sample (based on modal patli to war) +

Fought from War Joiner in Beginning an Ongoing War

UK-GER UK-IT Noncontiguous UK-JN

US-CH 1 3

4 0

FR-GER IT-AH RUS/USSR-JN RUS/USSR-CH

Contiguous

Likelihood ratio, p =.01a Corrected Yule's Q = -.85

Phi=-.77 p =.03

(+) The Goertz and Diehl sample consists of 11 cases; the 3 not included here have no wars for the relevant rivalry period (UK-RUS, US-UK, US-USSR).

(a) See Table 2. (b) See Table 2.

of -.75 and -.60 (and Phi's of -.62 and -.38).14 Rivals that are noncontiguous (have a lower score on contiguity) are more likely either to avoid war or to fight each other only in multilateral wars.

These findings (in Table 7 as well as Table 6) are also consistent with Thompson's (1995) recent claims that spatial rivalries, involving contention over territorial issues, and positional rivalries, involving contention over global politico-economic issues, evince distinct behavioral patterns. The latter, which almost always involve noncontiguous states, are, according to Thompson (1995:208-9), mostly pacific and less likely to fight directly the farther apart they are geographically. Conversely, the spatial rivalries, which often involved contiguous states fighting over territory, fight each other fairly frequently. Thompson focuses on the principal rivalries from the fifteenth through the twentieth centuries, so that four of his six centuries are independent from the data used here, yet his conclusions are very similar to the patterns delineated in this analysis.

14 The second Phi, aswould be expected given its magnitude, does not quite make the .05 significan-ce level, although it comes close with p = .06. Note here, however, as in Table 4, that contiguous dyads tend to become involved in more multilateral wars than dyadic wars. This has th-e effect of weakening the association even though- the th-eoretical explanation does not say contiguous states will not fight multilateral wars. In this way, the test is underestimating the strength of the hypoth-esis.




TABLE 7. Contiguity and the Two Paths to War

a. Goertz and Diehl (1995) (6 MID threshold) Sample

Rivalry-Producing No War or Wars; At Least One Multilateral

Dyadic War War

UK-RUS UK-GER

US-USSR UK-IT Noncontiguous US-UK UK-JN

US-CH

0 7

2 2

Contiguous RUS/USSR-JN FR-GER RUS/USSR-JN IT-AH

Likelihood Ratio, p =027a Corrected Yule's Q = .75b

Phi=-.62 p =.038


Rivalry-Producing No War or Wars; At Least One Multilateral Dyadic War* War+

Noncontiguous 0 14c

Contiguous 2 7d

Likelihood Ratio, p = .04a Corrected Yule's Q = .60b

Phi=-.38 p =.06

(*) Cases from Table 4, part b. (+) Cases from Tables 3, part b, and 4, part b. (a) See Table 2. (b) See Table 2. (c) Four dyads never fight wars and 10 fight multilateral wars. (d) Seven fight multilateral wars.



JOHN A. VASQUEZ 555

Conclusion The tests in this article are very encouraging. They show that one of the main factors that distinguish rivalries that go to war from those that do not is whether the rivals are contiguous or noncontiguous. In addition, there is a strong tendency for noncontiguous rivals to go to war primarily by joining ongoing wars. This process usually occurs through a rival's being brought into an ongoing war, but it can also occur through states' participating in a multilateral war fairly soon after it is initiated. These findings provide clear empirical evidence that the existence of two distinct paths to war is not just a logical possibility, but a behavioral regularity that needs to be recognized in the construction of test designs. Other analyses of contiguity have neither tested nor shown this.

The use of two different operational definitions of rivalry-one fairly restricted (6 MID threshold) and the other fairly broad (2 MID threshold)-also produced interesting and unexpected findings, although all the hypotheses passed tests based on the two samples. Still, the more restricted Goertz and Diehl sample generally produced stronger findings and a better fit than the 2 MID sample of Wayman. This makes clear two findings that were not really known before the analysis. First, rivals in the Goertz and Diehl sample better depict the two paths to war. The major reason for this was uncovered serendipitously in the analysis presented in Table 6. When forced, for measurement reasons, to code rivals on the basis of their typical (modal) path to war, it was found that contiguous states generally fight dyadic wars whereas noncontiguous states, when they fight, generally fight multilateral wars, and often join the latter late rather than in the beginning. Without looking at the modal path to war rivals take, this relationship, although still present, is somewhat muted. The reason is that contiguous states are also often brought into large wars, even though that is not their typical path to war. Nevertheless, it is rare for major states whose core territory is noncontiguous to fight wars one on one, even though for naval states or colonial competitors there are few barriers against doing so.

Second, given the results, it is clear that rivals in the Goertz and Diehl sample better fit the territorial explanation being tested in this analysis. For whatever reason, these rivals, as opposed to the set identified by the broader 2 MID threshold, tend to go to war in a manner slightly more consistent with that predicted by the territorial explanation. This leads us to ask what distinguishes the two samples.

By definition, the Goertz and Diehl rivals have more confrontations and more of a persistent pattern of disputing. This suggests that less intense rivalries are more subject to anomalous patterns, but not so much as to make the predicted relationships disappear. Specifically, the real difference is that in the less intense rivalries, contiguous states are brought into multilateral wars more frequently than are the contiguous states who have intense rivalries (cf. Table 4, a and b). The latter fight more dyadic wars and wars over territory, as is predicted by the territorial explanation. Less intense and short-term rivalries appear to go to war with each other because of the wars of others. A number of the rivals that are omitted by Goertz and Diehl seem to be of this ilk-FR-IT, FR-RUS, IT-RUS, FR-AH, RUS-AH, US-JN, US-GER-although only further research can make this conclusion definite. If this is found to be the case, then it may be because such rivalries lack the level of hostility discussed in the first section of this article. At any rate, it is the case that the more restricted sample, which is presumed to contain the more hostile rivalries, better fits the propositions being tested.

Of more immediate theoretical importance is that the findings are consistent with the territorial explanation of rivalry and war, which states that rivals that have territorial disputes are much more apt to go to war than rivals that do not. These other rivals that go to war probably do so through a process of war diffusion. Despite the preliminary nature of these tests, they do show that this theoretical analysis can




accurately explain how rivalries result in war and that it is able to distinguish rivals that do not go to war from those that do.

Those who would object to this conclusion would reply that the use of contiguity as a measure indicates only that those that have more of an opportunity to fight will fight more frequently than those that do not. An inspection of the contiguous rivals that go to war, however, shows that all these dyads-FR-GER, IT-AH, PRUS-AH, GER-RUS, RUS/USSR-JN, RUS/USSR-CH-go to war not simply because they have the opportunity to do so, but because they all have very serious issues under dispute.'5 Furthermore, these issues are not of a random nature; all involve territorial disputes. The tests show that work on a territorial explanation of rivalry is worth investigating further and should not be dismissed a priori by a proximity explanation, although the proximity explanation is a legitimate alternative interpretation for some of these findings in the absence of precise measurement of the issue content of rivalries.

The most severe limitation of the tests is the use of contiguity as an indirect measure of territorial disputes. Getting data on the latter would be a way of discriminating between the territorial and the proximity-interaction explanations. In addition, more in-depth case studies ofwhether noncontiguous rivals are brought into wars because of the territorial disputes of their allies would provide an additional test of the explanation and further elucidation on whether and how territorial issues are behind rivalry and war (see Vasquez, 1996a, 1996b).

The findings of this analysis, particularly the uncovering of two paths to war, are also consistent with Thompson's (1995) analysis that some rivalries (and wars) are basically spatial and over territorial issues, while other rivalries (and major global wars) are over posi

distinguishing rivals that go to war from those that do not: a quantitative comparative case study...

Documents