International Military Alliances, 1648-2008

International Military Alliances, 1648-2008


Edited by: Douglas M. Gibler


This inaugural title in the Correlates of War series from CQ Press catalogs every official interstate alliance signed from the Peace of Westphalia in 1648 through the early 21st century, ranking it among the most thorough and accessible reviews of formal military treaties ever published. Maps and introductions showcase the effects of alliances on the region or international system in century-specific chapters, while individual narratives and summaries of alliances simultaneously provide basic information, such as dates and member states, as well as essential insights on the conditions that prompted the agreement. Additionally, separate and/or secret articles are highlighted for additional context and interest.

  • Citations
  • Add to My List
  • Text Size

  • Chapters
  • Front Matter
  • Back Matter
  • Copyright

    View Copyright Page


    I pen these lines with pleasure, vindication, and anticipation. The pleasure is in introducing International Military Alliances, 1648–2008, the inaugural title in the Correlates of War Series. Douglas Gibler, a resourceful, thorough, and capable scholar, has devoted a significant share of his early career to producing this valuable opus, which carries us as far back as the Treaty of Westphalia in investigating the complex and elusive link between alliances and war.

    When my students and I launched the Correlates of War project, there was no question that a long historical sweep would be essential. It was at the height of the Cold War. We had survived the Cuban missile crisis; the assassination of President John F. Kennedy was just ahead; and I was dissatisfied with the way in which the Soviet-Western rivalry was being interpreted on both sides of the iron curtain. The policy analysts and scholars were firmly attached to their respective scenarios; the historians and political scientists were largely content to draw their lessons of history from the recent past, and few of us were embarrassed to trot out the Munich crisis of 1939 and the 1941 attack on Pearl Harbor as the bellwether events of our age. We clearly needed to take a longer view. Although I was quite willing to go back to 1815 and the Congress of Vienna, some thought that the nineteenth century offered little of value in helping us understand the twentieth century: it was not relevant; it was a different world.

    But some—I think immediately of Jack Levy and Claudio Cioffi—thought that we needed to go farther back in international history. It is to Doug Gibler's credit, and that of his mentor, John Vasquez, that he took up the challenge. The scholarly inadequacies that had prevailed during the Cold War had been exacerbated by a limited frame of historical reference. To the extent that this inaugural study in the Correlates of War series will lead to an increase in systematic and more scientific research over a more respectable time horizon—and we may hope that it will—it stands also to lead to a more nuanced understanding of world politics during the past two centuries. Given how badly we have grasped the realities since, let us say, the guns of August 1914, this longer view should help reduce unnecessary conflicts in the future, not to mention the ones that are unfolding in our immediate global environment.

    Some may express doubts as to the scientific value of these volumes. As far back as the Wages of War, which Melvin Small and I published in 1972, some of our more enthusiastic quantitative colleagues noted that for research purposes accessing the ever-expanding sets of data by computer is more efficient than scanning, copying, or otherwise downloading all these data matrices from the hard-copy pages of a real book. This is true, especially since the National Science Foundation has begun to require that any project it funds be made publicly available in relatively short order. However, it is one thing to have the numbers and quite another to comprehend their significance, such as the theoretical premises behind the data acquisition, the reasoning that justifies the data populations and samples, and perhaps the coding rules themselves. With International Military Alliances and the large number of data sets now available through the Correlates of War team at Penn State and other universities, the user of such data is no longer “flying blind” or, shall we say, need not do so. An increasingly large fraction of data sets are described and justified in journal articles and data descriptions, and that is as it should be.

    As a result, we can expect less sheer number crunching and a healthy increase in that scientifically desirable combination of theoretical awareness and sophisticated statistical analysis. International Military Alliances will surely accelerate that trend, and I commend it with pleasure and confidence.

    —J. David Singer

    Correlates of War, founder

    Introduction: Research and Methodology

    These two volumes compile and describe in detail every interstate formal alliance signed since the Peace of Westphalia in 1648. There are more than 450 alliances from 1648 to the present that meet the criteria of formal interstate alliances, and for each case commentary is provided in the form of several paragraphs on the background and history surrounding the formation of the alliance as well as, in some cases, the effects of the alliance on the region or international system. In addition, commentary often notes when states joined or left an alliance and when (or if) the alliance was abrogated. This detailed commentary supports the actual text of the alliance, if available in English, or an English translation of key alliance terms if no English text is available.

    This book is intended for students, researchers, and casual readers as well. For students, the case descriptions and the treaty texts should provide an important supplement for many graduate and undergraduate classes in international relations and diplomatic history. For researchers, the commentaries often include discussions of key coding decisions, and the treaty texts will provide a single resource for invaluable information on all international military alliance commitments. Finally, for the casual reader, the summaries are written in a nontechnical style intended to guide the reader who is trying to understand the historical importance of particular alliance treaties.

    What follows in this chapter is an introduction to the book that is organized around the central question that has motivated the majority of alliance scholars: How do international alliances affect the prospects for war? The introduction begins by defining what scholars mean by the term military alliance and then describes the historical debates that have associated alliances with both peace and war. The collection of alliance data, such as the data set included in this volume, has been the key impetus for alliance scholars to move beyond impassioned, anecdotally driven debates that resolved few questions. When J. David Singer and Melvin Small introduced the first alliance data in 1966, scholars were finally able to systematically test the effects of alliances.

    Although a great deal of knowledge about alliances has been amassed in more than forty years since the first systematic study, problems persist in the research on alliances. One of the central problems of alliance research is that scholars have not adequately considered that alliances vary substantially as a class. Thus, the final sections of this introduction describe several different ways of conceptualizing alliances, including one framework based on the characteristics of the states making an alliance and one framework based on Singer and Small's original typology of alliance terms. A short guide to the entries in these volumes is provided in the section on how to use this book that follows this introduction.

    What Is an International Alliance?

    An alliance is a formal contingent commitment by two or more states to some future action. The action involved could entail almost anything—detailed military planning, consultation during a crisis, or a promise by one state to abstain from an upcoming war. Once reached, the agreement is usually in written form and is made public to other states in the system at the discretion of the states making the alliance. Though less important today, secret alliances and commitments have affected the outcomes of many crises, battles, and wars. For example, the Hitler-Stalin pact (1939), with its many secret accords, immediately sealed the fate of the much weaker Poland.

    Alliances have been widely discussed by students of international relations because hundreds or perhaps thousands of interactions may take place between states in any given year, but few interactions create the impact meted out by alliance formation. This impact allows alliance behavior, unlike most other forms of international actions, to be quite open to systematic investigation (Singer and Small 1966, 1). Despite the ease of tracing these actions, however, researchers have often disagreed over what constitutes an alliance commitment. Issues of trade and legal reciprocity are often ignored even though these may constitute a large portion of an alliance relationship (Ward 1973), and alliances never formalized by treaty are omitted from most alliance data sets.

    Although conceptual problems persist, empirical studies have developed a consensus that operationalization of the alliance variable depends on two factors. First, alliance members have to be independent nation-members of the international system (for example, so-called alliances between international terrorist organizations do not qualify), and second, a treaty text has to exist that identifies a military commitment that is defensive, a neutrality arrangement, or an “understanding” such as an entente (Singer and Small 1966). Lists of the alliances that meet these criteria have been printed in various forms (Singer and Small 1966, 1968, 1972; Small and Singer 1982; Gibler and Sarkees 2004). A current listing is available from the Correlates of War project.

    Alliances, Peace, and War

    Traditional international relations theories have associated alliances with both peace and war. Alliances that “correctly” balance the system are supposed to lead to peace, while incorrect balancing makes war more likely. This section describes these theories.

    Alliances and Peace?

    Alliance theory originally developed as an extension of balance of power theory; alliances were formed to make sure that the capabilities of major state coalitions remained relatively equal. Equality of power was believed to promote peace because it was thought that no sane leader would risk a war if there was a 50 percent chance of losing; war comes with preponderance, that is, when a state has an easier chance of winning. At the state level each nation has the choice to either arm itself or pursue a policy of alliances when confronted with the prospect of a possible threat (Most and Siverson 1986; Walt 1987; Waltz 1979). If a nation chooses to arm, it risks an endless spiral of increasing armaments that could result in an arms race. According to balance of power theory, choosing alliances allows states to respond more quickly and with more precision to increased threats from other states. Diplomats and international leaders are able to use alliance networks to properly balance the capabilities of opposing nations to maintain peace in the international system. Alliances, in this framework, function only to serve the balance of power.

    Alliance commitments are also said to reduce the level of uncertainty in the system and minimize the likelihood of war that may result owing to misperception and miscalculation (Singer, Bremer, and Stuckey 1972, 23). These commitments can also reduce the chances of catastrophic shifts in the systemic balance of power (Osgood 1967, 86). Some balance of power theorists claim that alliances are also necessary to avoid the most dangerous wars. A belligerent world power, seeking domination of the system, would likely restrain itself when confronted with an alliance system poised against it. Alliances, then, are an indispensable means of maintaining equilibrium in the system (Gulick 1955, 61–62).

    Alliances are also thought to preserve peace in other ways. Major states may use alliances to constrain revisionist alliance partners, or an alliance can preserve peace by enhancing the prestige of a failing power whose collapse could be destabilizing to the international system (Liska 1962, 31–32, 37–40). Many neo-realists argue that these alliances become meaningless in periods of bipolarity because the major state has enough capabilities to ignore the belligerent policies of its weaker allies (Waltz 1979, 169). Nevertheless, even intense periods of bipolarity have seen the growth of intricate alliance systems.

    Alliances and War?

    Waltz's observation that the major state must have enough power to ignore the policies of its allies was a response to anecdotal evidence that weaker allies tended to bring major state allies into expanded wars—an observation that has since been confirmed by more systematic investigations (Siverson and King 1979, 1980; Yamamoto and Bremer 1980).

    That minor states bring major states into war is only one hypothesis linking alliances to war in the traditional literature. Traditional arguments linking alliances to war are as numerous and varied as those associating alliances with peace. For example, a state seeking alliances to show resolve could be interpreted by another state as attempting a strategy of encirclement. The targeted state would naturally respond by seeking counteralliances (Kaplan 1957, 24; Wright 1965, 774). Although such alliance partners may have been hard to find prior to the signing of the initial alliance, the developing cleavages could make other states more likely to become involved (Ray 1995, 375). The polarized system or region could also simply clarify the situation and make it easier for the aggressor to determine its odds of winning. As Bueno de Mesquita (1981, 151) notes, “The reduction of uncertainty brought about by such information may be all that is needed to facilitate an aggressor's desire to attack another state.”

    Balance of power theory can also support the existence of large, systemwide wars against potential dominance caused by alliance formation. In the example given above, the revisionist state is seeking dominance of the system but is confronted with an alliance against it. Instead of being rebuffed by this alliance, the revisionist state continues its policies and fights the war.1 As Levy (1989, 230) notes, a number of general wars during the past five centuries appear to fit this proposition. These include the “wars against Philip of Spain in the late sixteenth century, against Louis XIV in the late seventeenth century, against revolutionary and Napoleonic France a century later, and against Germany twice in this century” (Levy 1989, 230–231).

    As is obvious from these debates, no clear understanding of the relationship between alliance formation and war has ever been developed. Alliances in the traditional literature have been revered as sources of peace when they have acted as balancing agents and reviled as sources of war when the same alliance system breaks down. Based mostly on logic and historical anecdote and often mired in post hoc balance of power explanations, the traditional literature has not produced a convincing, consistent, theoretical explanation of the relationship between alliances and war. Not until the investigatory process turned empirical did researchers begin to start a process of accumulation that has provided many of the answers to the alliance-war puzzle.

    Importance of Good Data

    Part of the problem leading to such differences across theories and results was the relative dearth of data on interstate alliances. For most of the early studies, no consistent agreement existed on what constituted a military alliance, and certainly no repository of data existed with which to test the various theories. That all changed in 1966 when J. David Singer and Melvin Small released the first data set on international alliances. This release, along with the release of an expanded data set three years later, established detailed coding criteria upon which all Correlates of War formal international alliance data sets have since been assembled: First, at least two members of the alliance must be qualified system members; second, the alliance must be a defense pact, neutrality or non-aggression pact, or an entente; and third, the effective dates of alliance have to be identified. Implicit within this definition is the formality of the agreement; a formal alliance is a written agreement that identifies at least the members and the obligations of each alliance member (Singer and Small 1966, 1–6; Singer and Small 1968).

    There were also several less well-known characteristics of the Correlates of War alliance data sets that were consequences of both Singer and Small's research goals and of the computer technology of the time. Singer and Small were primarily interested in investigating the relationship between alliances and the onset of interstate war. Thus, no alliances were included that “were consummated by nations while participating in war or within three months prior to such participation, unless those alliances emerged from the war intact” (Singer and Small 1968, 262). Beginning dates and ending dates of the alliances were also given only in terms of month and year. The alliance type was coded as “1” defense pact, “2” neutrality or non-aggression pact, or “3” entente. Type 1 alliances imposed a higher level of obligation on the signatories than the Type 2 alliances, and both Types 1 and 2 imposed greater obligations than Type 3 alliances. As Singer and Small (1968, 280n10) note, however, Type 3 ententes and Type 2 non-aggression or neutrality pacts often had a greater historical impact on the international system than Type 1 defense pacts, depending on the states involved in the alliance.

    Finally, although the journal articles presented the data in an alliance list format, the data were more generally released in the form of alliance bonds (by the Inter-University Consortium for Political and Social Research, for instance). Singer and Small had a particular interest in dyadic alliance relationships and their impact on war initiation; thus, only the highest level of alliance obligation between a pair of states in a given year was coded. This forced multiple alliance types to be ignored, and lower-level agreements ended with the signing of a defense pact. Similarly, ententes signed while a defense pact was in force were not included.

    These coding decisions were tied to both a specific research agenda and the extant computer technology. As technology has changed, the data have been improved and expanded. Revisions of the data also began to include alliances created during wartime and alliances that reflected simultaneous alliance obligations. There was also an attempt to add greater specificity to the beginning and ending dates of alliances. Thus, the data contained in these volumes represent a much larger sample of the interstate alliances formed since 1816 than did earlier works.

    Also contained in these volumes is an extension of the original data to include the years between 1648 and 1815. This extended data set was developed for several reasons, but most important, after the outstanding early work of J. David Singer, Melvin Small, and the Correlates of War project, most studies limited themselves to analyses from the post-Napoleonic period to 1965, 1980, or to whatever year the data had been updated. This was unfortunate because often many inferences were drawn from temporally limited data sets, which did not include even the largest wars of the nineteenth century. This was probably why most alliance researchers noted that the nineteenth century was much more peaceful for alliance formation than the twentieth century.

    The year 1648 was chosen as the beginning of the extended data set for several reasons. First, the Peace of Westphalia has often been considered the beginning of the international state system as it was the first peace to recognize both territorial sovereignty and autonomy—the liberties of states (Holsti 1991). Second, it represented a period during which alliance formation was quite frequent (because of the states’ newfound freedom, presumably) and varied (Parry 1978). Third, the century and a half after Westphalia provided an opportunity to accumulate a data set that was large enough to be theoretically interesting yet still remain small enough to be manageable. In other words, an additional 160 years of data could answer questions regarding the uniqueness of the nineteenth century but was limited enough in scope to be completed in a timely fashion. Fourth, the manageability of a data set extension to Westphalia was greatly aided by new treaty sources accumulated during the past twenty years—sources that were not available to previous alliance scholars. Parry (1978, index volume I, ix), for example, provided a compilation “comprehending all treaties from the Peace of Westphalia of 1648” up to the year 1851.

    Combined, the two data sets represent a comparable set of more than 450 cases of alliances that span more than four centuries. These cases, especially the early Correlates of War data sets, were of great importance for answering many of the questions in the traditional literature on alliances. Instead of relying on arguments supported by anecdotes, the new data sets allowed international relations scholars to systematically test, revise, and retest their theories, a process that has ultimately contributed to a great deal of accumulated knowledge about the effects of alliance formation. The next section describes many of the most influential of these studies.

    Systematic Studies of Alliances

    One of the first empirical tests of the alliance-war relationship was Singer and Small's (1966) examination of the behavior of major states. They found that states ranking high on alliance activity also rank high on war engagement, initiation, and battle deaths. This study provided the first systematic evidence that alliances were associated with war, which contradicted the traditional, realist balance of power literature. Following this work, Wallace (1973) and Bueno de Mesquita (1975, 1978) examined the effects polarization has had on war onset. Wallace found that very high or very low levels of polarity in the system produced war. Refining the indicators of polarity, Bueno de Mesquita showed that the “tightness” of an alliance system is not necessarily related to war onset. He found, however, that increases in the tightness of alliances are correlated with war. Discrete alliances, on the other hand, are not associated with war.1

    Levy (1981) reformulated the questions about alliance formation and war and with a limited extension of the Correlates of War data found that, with the exception of the nineteenth century, most alliances are followed by war. More significantly, a relationship between power and alliance formation was found: all so-called great power alliances in the sixteenth, seventeenth, and twentieth centuries were followed by war within five years (Levy 1981, 597–598, tab. 7).

    Alliances between major states may also be linked to increased probabilities of war in a second and less obvious way, according to Vasquez (1993, 163–164). Schroeder (1976) has discussed how major, “predatory” states may sign non-aggression pacts in order to remove potential adversaries before attacking smaller states. Moul (1988, 34–35) shows that there is an increased likelihood for unequal states to go to war in the presence of a non-aggression pact with another state. These pacts of restraint, or pacta de contrahendo, limit the expansion of war but promote hostilities between unequals.

    The studies by Moul (1988) and Schroeder (1976) are important indicators that alliances can, in some instances, be used as methods of limiting the expansion of war. In most cases, however, alliances have been shown to be an important link in the spread of war after war begins. For example, Siverson and King (1979, 1980) have shown that participation in a multilateral war is often determined by alliance ties. The presence of alliances contributes to expanded wars as smaller states bring their major state allies into their wars. A similar analysis links alliances to the types of wars fought. Vasquez (1997) has shown that wars among noncontiguous, rival states almost always happen in the presence of an alliance. The original territorial issue that begins a conflict will drag noncontiguous allies into an expanded war; the implication is that, had the alliance not existed, the war was much more likely to remain bilateral.

    Alliances may also have some unanticipated effects regarding which side states choose to fight on in a coming war. A small literature exists on the probability of friends becoming foes. Expected utility theory notes that it is sometimes rational for allied states to end up in war with each other instead of against a common foe (Bueno de Mesquita 1981). Most arguments start between friends or acquaintances, and it follows that alliances may increase the probability of war between states. Ray (1990), however, has noted that this probability is quite small and is dependent on both the definition of war and the definition of alliance (in both cases, dyadic or multilateral). Bremer (1992) has seemingly ended this controversy by controlling for the proximity of the allies. Noting that allies are more likely to fight each other than unallied states, Bremer also finds that the addition of contiguity into a multivariate analysis eliminates the relationship between alliance ties and war. Although the logic of opportunity is consistent with Bueno de Mesquita's argument, Bremer's findings suggest that allies are becoming foes not because of their alliances but because they are neighbors. Allies that are not neighbors are not likely to go to war with each other. Bremer (1992) did find, however, that allies that were highly militarized had an increased chance of fighting each other. This suggests that Bremer may have statistically isolated the cases in which alliances promoted war between signatories.

    Despite these results, the dangers of alliance formation should be noted. Alliances generally increase rather than decrease the chances of war against nonallied states, and even Bremer's research has shown that alliances can increase the chances of war even against allies in certain situations. Both these findings run counter to realist prescriptions advocating the quickly formed alliance, and both underscore the dangerous potential that alliances can have for naive policymakers.

    The findings presented above, which show that alliances are often associated with war, have been tempered, however, by their inability to explain a large number of anomalous, peaceful alliances. Nineteenth-century alliances, for example, were much more likely to be followed by peace than by war. Maoz (2000) and Levy (1981), among others, have clearly shown that many alliances are not followed by war. The presence of these peaceful alliances makes it difficult to come to any definitive conclusions on alliances as a correlate of war.

    Conceptualizing Alliances

    One major reason for the lack of conclusive evidence regarding the relationship between alliances and war is the lack of proper conceptualization. For example, almost all the studies that use the Correlates of War data have grouped many different types of alliances as similar cases. This groups the Hitler-Stalin pact (1939) together with peace settlements that settled major wars, like the Quadruple Alliance of 1815 signed during the Congress of Vienna. As with these two cases, the effects of most alliances are of course going to be dependent on the intentions of the leaders making the alliances. The difficulty, however, rests in determining the intentions these leaders had when the alliances were formed.

    Although some scholars have concentrated on the actual terms of the alliances for differentiating across alliance types (see Singer and Small 1966; Leeds et al. 2002), a more fundamental way of understanding leader intentions comes with a quick look at some simple characteristics of the states that sign an alliance. Alliances can be formed with almost any type of state in the international system; thus, important information can be found in the types of states that a leader chooses for allies. Think of it this way: if a leader chooses to ally with a state of lesser power, that leader is probably not interested in using the alliance to aggregate the power of the states against a common foe. Similarly, if a leader chooses to ally with a state with foreign policies that have differed from the leader's policies, it would be unlikely that the leader expects to trust the ally enough to fight together in defense. Figure 1 puts these two core concepts—interests and capabilities—together in tabular form.

    Group A, the category of extended deterrence alliances, consists of alliances dominated by one state in a bilateral alliance or by a few states in a multilateral alliance. General agreement among alliance members suggests that these asymmetric alliances are likely to be vehicles of extended deterrence. The smaller states gain security against rivals or possible predatory major states, but because the smaller states already agree with the policy position of the major state, the major state is likely to gain few tangible benefits in the exchange. Intangible benefits then become the focus of the alliance for the major state and include such things as war avoidance, protection of similar interests, and perhaps the ability to foster even more agreement in smaller alliance partners.

    The North Atlantic Treaty Organization (NATO), established in 1949, is one of the prime examples of this type of alliance. On average, alliance members generally agree on major policy initiatives; however, this particular alliance continues to be dominated by the United States. During the cold war, Western Europe received increased security benefits against possible Soviet aggression, and the United States maintained the ability to have some say in European politics as part of preserving the peace. Calls for expansion of NATO emphasize the ability of the alliance to provide security for smaller states as they democratize and become more “Western” in their interests (Gibler 1999; Gibler and Sewell 2006).

    Group B alliances, imposed alliances, differ from NATO and other alliances with shared similar interests because the interalliance level of agreement is not high. This low level of agreement obviously makes it difficult for these alliances to form, but if they do form, they are likely to offer the major state tangible benefits in return for the provision of security. Tangible benefits are likely to include the provision of military bases, oil, or geostrategic position that traditional theorists such as Morgenthau and Thompson (1985, 204 ff) suggested, but these alliances may not be the choice of the minor state. In other words, the major state demands a military presence in a particular area and is willing to provide its brand of security to the minor state alliance partner in exchange for access to the area. These were the alliances of the Soviet Union and satellite states following World War II as well as the nonideological alliances of the United States during the cold war. Throughout history, the search for spheres of influence has been manifested in this alliance type.

    Group C alliances, capability-aggregating alliances, represent the alliances commonly thought of in balance of power theory. These alliances are formed by states with similar interests and similar capabilities and are likely to be used to either avert or win a coming conflict. The benefit of security is spread throughout the alliance, but it is often unclear, at least for adversaries, whether the alliance is going to be defensive or offensive. The targets or neighbors of these alliances have to look for clues as to the intentions of the alliance members. In the case of postwar defense pacts that are often meant to ensure the peace that was signed, the international context sometimes determines the use of these kinds of alliances.

    Group D alliances, single issue alliances, are similar to Group B alliances as they comprise states with little or no harmony of interests; in this group, however, the alliances cannot be imposed because capabilities are relatively dispersed throughout the alliance. These alliances tend to be specific agreements pertaining to only a few issues because overall issue agreement does not exist. The pacts of restraint identified by Schroeder (1976) and Moul (1988) are likely to be of this type. Major states with disparate interests may agree only that a conflict should be limited, and the alliance serves as permission for the coming attack and a guarantee against the expansion of conflict. For example, Hitler and Stalin agreed on very little before their 1939 non-aggression pact. The alliance itself then focused on the limited issues of division of territory and neutrality in the coming war. Group D alliances are asymmetric in the provision of benefits but symmetric in the distribution of capabilities throughout the alliance.

    Notice the advantages of combining both capabilities and interests together in this model. Capabilities in isolation cannot discern the differences between the pacts of restraint and the capability-aggregating alliances—the Hitler-Stalin pact looks the same as the Anglo-French alliance prior to World War II because both are among relative equals. Similarly, capabilities cannot differentiate among the imposed alliances creating spheres of influence and the alliances meant to provide deterrence for friendly states. The distribution of interests in alliances adds a tremendous amount of information to aid the understanding of specific alliances, and it does so in a relatively simple way.

    This framework allows readers to quickly evaluate the alliances found in these volumes. The terms of an alliance (defense pact, neutrality or non-aggression pacts, and ententes) provide a great deal of information, but often these terms are not enough to gauge how an alliance treaty was to be used by the signatories. If the terms of the alliance are combined with the interest-capability framework, however, readers of these volumes can easily deduce that a major state is not expecting a smaller state to come to its aid when they sign a defense pact. Or, similarly, defense pacts between similarly capable states with vastly different interests are usually meant to resolve particular issues of contention.

    The remainder of this chapter describes the collection of alliance treaties included in these volumes. The following section begins with an outline of the method used to identify potential treaties and includes a discussion of how this process complements the original data sets developed in the 1960s. The final part of the section explains the criteria that determine when a formal international treaty is an international alliance, and, thus, it provides an important guide for all the treaties included in these volumes.

    Identifying and Describing Alliances in These Volumes

    This section describes the alliances that are included in these volumes. As noted, the 1648 to 1815 cases were identified in the author's research (Gibler 1999). The 1816 to 2000 data included revisions of the original Correlates of War data that became version 3.0 of that data set (Gibler and Sarkees 2004). Finally, the alliances signed after 2000 that are included in the second volume represent the beginning of a revision (version 4.0) of the Correlates of War data set.

    Defining Formal Alliances

    For the purposes of this data set, written agreements are major indicators used to determine the existence of an alliance. This is perhaps the greatest change from the original alliance data sets. Although Singer and Small relied primarily on the written alliance agreement in defining alliance types, they also supplemented this research with interpretations by diplomatic historians, particularly if the treaty text contained any ambiguities (Singer and Small 1966, 5; 1968, 261). However, historical opinion is no longer as decisive for these data because historical scholarship on particular cases has changed greatly over time, and the alliances were often used in ways contrary to the actual terms of the treaty. For example, ententes were sometimes more likely to resemble defense pacts than agreements to consult during crises. Therefore, instead of a reliance on the secondary historical record, only formal, written treaties that meet Singer and Small's original definition of alliance are included in these volumes, with two important exceptions.

    First, written treaties that do not pass the ratification process are not included. Several South American treaties during the nineteenth and early twentieth centuries failed to win legislative approval following negotiations, and at least one treaty was eliminated because the alliance negotiator, Bismarck, intentionally failed to sign the final treaty.1

    Second, several alliances were identified as meeting the Singer and Small definition, but the actual treaty text could not be located. For example, the terms of a few recent alliances were confirmed by multiple press accounts, but the actual treaty texts have not been deposited with the United Nations or otherwise released in full to the public. The texts for a few nineteenth-century treaties have not been reprinted, were never cataloged in the various treaty collections, and should probably be considered lost. Alliances with no surviving treaty texts were included in this data set only when their existence and characteristics could be confirmed by at least two secondary sources. This decision rule adds only one alliance before 1945—an alliance between France and Sardinia in 1859. In all, forty-one other alliances are included on the basis of secondary sources only; all were signed after 1945, with more than half formed after 1980.

    Sources Used

    The generation of this data set began with the various data sources currently available—the original Correlates of War data set and the various independent updates. These data sources were augmented with new United Nations data and several new anthologies that were released after the last revision of the Correlates of War data. In addition, Lexis-Nexis, Keesing's, and Facts on File were used for every year available (the years vary according to each source) to update the twentieth- and twenty-first-century alliances.

    Secondary historical sources were used to collect background information on the duration of each alliance (exact abrogation or termination dates), and, as mentioned above, secondary sources were also used to identify the existence of a formal alliance when no treaty texts could be identified. For more than 95 percent of the alliances identified using secondary sources, at least one secondary source contained excerpts of the alliance; thus, confirmation of the terms was consistent with treaties for which the full text was available.1 Once again, in emulation of the Singer and Small data collection procedures, secondary sources for these volumes were chosen carefully to ensure global coverage during the entire time period.1

    Alliance Sources and Avoiding Missed Alliances

    Researchers at the Correlates of War project have always believed that using multiple sources from a broad array of geographic and historical perspectives is the best way to try to identify the universe of formal alliances (Singer and Small 1966). Unfortunately, it is not easy to avoid omissions in this type of research because alliances may exist that were never registered, were never included in anthologies, and were never mentioned by historians. The prospect of these missing alliances is troubling, but the vigorous data collection procedures used give an accurate representation of the universe of alliances during the years since 1816.

    As a reliability test of the methods used to collect these alliances, twenty state-year periods of ten years were chosen randomly and were then independently investigated by several coders not involved in the original construction of the data set. These in-depth investigations also focused on secondary sources not originally used in the construction of the data set. In all but one of these twenty investigations, the alliance portfolio produced by these more intense investigations matched the original alliance portfolio. In the only aberrant investigation, a single alliance was added to the current data set. Given these reliability results, one can be fairly confident that the prospects for Type I errors in this data set are low.

    The original Correlates of War data collection was compiled using the League of Nations Treaty Series, Britain's Foreign and State Papers, as well as various historical monographs. To avoid subjecting the data collection to particular geographic or cultural biases, researchers included samplings of works from several different historical schools and from several different areas of the globe (Singer and Small 1968, 1–2). Maintaining this extreme effort to reduce bias was not necessary with the data extension, however, because of the recent compilation of the Consolidated Treaty Series. This series, edited by the late Clive Parry, presents a complete collection of printed treaties since 1648 in their original languages and with French and English translations where they exist. Parry (1978, preface) included treaties regardless of where they were signed or which states (or non-states) were the signatories.

    Although the Parry collection (1978) does represent the universe of written treaties from 1648 to 1851, the accuracy of each alliance found in the Parry collection has been verified using external sources. The original sources, cited by Parry, were consulted to verify the authenticity of the treaty text, and independent historical monographs and chronologies—especially Albrecht-Carrié (1958), Babuscio and Dunn (1984), Dupuy and Dupuy (1977), and Langer (1972)—were searched for information about each document. To qualify as an alliance in the 1648 to 1815 data set, the document had to meet the requirements of system membership, alliance commitment, and be mentioned in at least two secondary sources independent of Parry's collection (once again, for most of the alliances these sources were Langer [1972], Albrecht-Carrié [1958], and Dupuy and Dupuy [1977]).

    Criteria for Identifying Formal Interstate Alliances

    As mentioned above, the Correlates of War definition of a formal international alliance has three explicit criteria: first, the alliance must be signed by two qualified system members; second, the alliance treaty must contain language that would qualify it as a defense pact, a neutrality or non-aggression pact, or an entente; and third, the effective dates of alliance have to be identifiable. Each of these criteria is discussed in turn.

    System membership

    The original Correlates of War state system membership criteria were first developed in Russett, Singer, and Small (1968) and were later expanded in Singer and Small (1972) and in Small and Singer (1982). The criteria include states that (1) have a population greater than 500,000, and (2) are “sufficiently unencumbered by legal, military, economic, or political constraints to exercise a fair degree of sovereignty and independence” (Singer and Small 1972, 20). The second criterion was operationalized prior to 1920 as recognition by Britain and France, and after 1920 as formal recognition by any two major states or membership in the League of Nations or United Nations.1 The latest version of these data is available at

    These volumes draw upon an original data set of system membership for the period between 1648 and 1815. Corresponding to the Correlates of War data set for the post-1815 period, this data set is divided according to whether a system member is either a major or minor state in the system. Each of these membership statuses is discussed in turn.

    Because Correlates of War definitions of system membership exist only for the post-1815 periods, this data set required a functional equivalent that would be compatible with the traditional definitions of major and minor status. Levy (1983) provides an important beginning as he relies on careful historical research to identify the composition of what he terms the “modern great power system.” A great power, according to Levy (1983, 16), is “a state that plays a major role in international politics with respect to security-related issues.” Great powers possess the military might to impose their will on lesser states and the ambition to have their own interests commingle with “systemic interests” (that is, the international balance of power). These states are also quite active in the international system, and this activity engenders a certain respect by other great powers in addition to formal recognition by most other states. As Levy (1983, 18) notes, the Treaty of Westphalia “named France and Sweden as the guarantors of the peace settlement” for good reason. These two states possessed all of the above characteristics, making them the great powers of that era.

    Levy's definition of great powers is used to indicate major status for the period between 1648 to 1815. This is a valid substitute measure because of the similarity between Levy's list of great powers and the Correlates of War list of major states for the post-1815 period. These two data sets differ only with respect to major status entry dates for four states,1 but they never differ regarding the identification of which states are considered major.1

    To meet the Correlates of War definition of minor status a state must have “all the traditional earmarks of nationhood” in addition to meeting two specific criteria: “(a) a population exceeding half a million and (b) de facto diplomatic recognition from the two nations that come closest to being the international community's legitimizers during the period under investigation….” (Singer and Small 1968, 3). Singer and Small argue that Britain and France were those two states for much of the post-1815 time period. As noted, however, the Treaty of Westphalia left Sweden and France as guarantors of the peace in 1648. Therefore, Sweden was added to the list of Britain and France as legitimizing states for the 1648 to 1721 time period. After 1721, when Sweden lost its major status, Britain and France remained as legitimizing states.1

    The population threshold for several candidate states was checked using various demographic histories (especially Babuscio and Dunn 1984; Cook and Paxton 1981).1 A lower population threshold was initially considered appropriate because of the lower world and European populations of this era, but this idea was dismissed as a revised population threshold for two reasons. First, no scaled population threshold was used by Singer and Small (1968), even though their data set spanned more than 150 years. Therefore, compatibility issues dictated an extension of the half-million threshold to 1648. Second, a more practical justification existed in the fact that few ambiguous cases present themselves; most treaties during this time period (the set of cases of which alliances are a subset) had major states as parties. Few treaties involved only minor powers (six out of eighty-two), and when they did, the minor powers always exceeded the half-million population threshold. These facts, combined with the aim of making the new data set compatible with the existing Correlates of War data, made it appropriate to maintain the population threshold for the entire 1648 to 1815 time period. The entire list of international system members and their dates of entry and exit are available in the index.1

    System membership affects the alliance data in several ways. Alliances created by one system member with one or more extra-systemic groups are excluded from this data set. However, if one of these groups gains system membership during the tenure of the alliance, the alliance is coded in the Correlates of War data as beginning on the second earliest system entry date in the alliance.1 For example, the United Kingdom and Iraq signed an alliance on June 30, 1930, but Iraq was not a system member. Therefore, the alliance has been coded as beginning on October 3, 1932, when Iraq gained system membership. When a state loses system membership—through civil war, loss in war, or political union—the alliance ceases to exist for that state. If only one member of the alliance remains a system member, the entire alliance is coded as ending.

    Alliance type

    Alliance type defines the level of support that an alliance member pledges to other alliance members. Defense pacts (Type I) commit states to intervene militarily on the side of any treaty partner that is attacked.1 Neutrality and non-aggression pacts (Type II) specify that parties remain militarily neutral if any cosignatory is attacked. The neutrality pact is usually more specific than the more sweeping non-aggression pact. Finally, ententes (Type III) pledge consultation or cooperation, or both, during a crisis, including armed attack. Broad, sweeping statements that pledge eternal friendship or observations of similar principles do not qualify as ententes in this version of the alliance data.

    Because the unit of the observation is the alliance itself, treaty texts that contain multiple alliance obligations are classified according to the most serious obligation. However, separate treaty texts that pledge different levels of cooperation and whose durations overlap extant alliance bonds are considered separate alliances. For example, a text that obligates members to defend each other if attacked and also pledges consultation is considered a defense pact. But alliance members that in March pledge to consult and in May pledge to defend each other in case of attack are considered members of both an entente and a defense pact unless the defense pact replaces the prior agreement.

    Alliance duration

    In determining the effective dates of alliance, the start date corresponds with the signature date of the treaty, even though ratification may have come much later. Alliances not ratified are excluded from the data set.

    Termination dates are more difficult to determine, although end dates could be either specified in the agreement, the result of a formal abrogation, the result of informal abrogation via explicitly recognized violations of the terms of the treaty, or via the assumption of new and incompatible obligations by one or more of the signatories (Singer and Small 1966). Many treaty texts state that alliances will last “in perpetuity” or will be renewed every ten or twenty years after the date of signature, provided both states agree. Although original alliances are often registered with international bodies (at least since the League of Nations), renewals are not often registered, and terminations rarely are. Given the complexity of determining when an alliance relationship ends, a clear set of procedures was developed that provides for greater consistency of application.

    First, the coding of the termination dates begins with the text of the treaty and its stated end date. Second, primary and secondary sources were consulted to determine whether a renewal took place. Third, primary and secondary sources were examined to determine whether abrogation occurred prior to the expected end of the alliance. Typical events causing abrogation include elevated levels of conflict like intense crises or wars or regime changes such as the disintegration of the Soviet Union and its satellite states. Given these rules, the termination date for a formal alliance is the stated end date if no renewal or abrogation took place. Otherwise, the end date of the alliance corresponds with the end date of the final renewal or the date of abrogation of the alliance.

    Termination dates are very difficult to determine for most of the alliances between 1648 and 1815. Formal abrogation seldom occurred, and alliance ties often shifted quickly between and even during conflicts. Therefore, the alliances included in these volumes from 1648 to 1815 are listed without termination dates. If an event occurred that clearly demonstrated the end of the alliance—most often a conflict between the allies—this is noted in the summary preceding the text of the treaty.

    Reference List

    Albrecht-Carrié, René. 1958. A Diplomatic History of Europe since the Congress of Vienna. New York: Harper & Brothers.

    Babuscio, Jack, and Richard Minta Dunn. 1984. European Political Facts, 1648–1789. New York: Facts on File.

    Bremer, Stuart. 1992. “Dangerous Dyads: Conditions Affecting the Likelihood of Interstate War, 1816–1965.” Journal of Conflict Resolution 36 (June): 309–341.

    Bueno de Mesquita, Bruce. 1975. “Measuring Systemic Polarity.” Journal of Conflict Resolution 19: 77–96.

    Bueno de Mesquita, Bruce. 1978. “Systemic Polarization and the Occurrence and Duration of War.” Journal of Conflict Resolution 22 (June): 241–267.

    Bueno de Mesquita, Bruce. 1981. The War Trap. New Haven: Yale University Press.

    Cook, Chris, and John Paxton. 1981. European Political Facts, 1789–1848. New York: Facts on File.

    Dupuy, R. Ernest, and Trevor N. Dupuy. 1977. The Encyclopedia of Military History. New York: Harper and Row.

    Gibler, Douglas M. 1999. “An Extension of the Correlates of War Formal Alliance Data Set, 1648–1814.” International Interactions 25 (1): 1–28.

    Gibler, Douglas M., and Meredith Reid Sarkees. 2004. “Measuring Alliances: The Correlates of War Formal Interstate Alliance Dataset, 1816–2000.” Journal of Peace Research 41, no. 2: 211–222.

    Gibler, Douglas M., and Jamil Sewell. 2006. “External Threat and Democracy: The Role of NATO Revisited.” Journal of Peace Research 43, no. 4: 413–431.

    Gleditsch, Kristian S., and Michael D. Ward. 1999. “Interstate System Membership: A Revised List of the Independent States since 1816.” International Interactions 25: 393–413.

    Gulick, E. V. 1955. Europe's Classical Balance of Power. New York: Norton.

    Holsti, Kalevi. 1991. Peace and War: Armed Conflicts and International Order, 1648–1989. Cambridge: Cambridge University Press.

    Kaplan, Morton. 1957. System and Process in International Politics. New York: Wiley.

    Langer, William. 1972. An Encyclopedia of World History. Boston: Houghton Mifflin.

    Leeds, Brett Ashley, Jeffrey M. Ritter, Sara McLaughlin Mitchell, and Andrew G. Long. 2002. “Alliance Treaty Obligations and Provisions, 1815–1944.” International Interactions 28: 237–260.

    Levy, Jack. 1981. “Alliance Formation and War Behavior: An Analysis of the Great Powers, 1495–1975.” Journal of Conflict Resolution 25 (December): 581–613.

    Levy, Jack. 1983. War in the Modern Great Power System, 1495–1975. Lexington: University of Kentucky Press.

    Levy, Jack. 1989. “The Causes of War: A Review of Theories and Evidence.” In Behavior, Society, and Nuclear War, vol. 1, ed. Philip E. Tetlock et al., 209–333. New York: Oxford University Press.

    Liska, G. 1962. Nations in Alliance. Baltimore: Johns Hopkins University Press.

    Maoz, Zeev. 2000. “The Street-Gangs of World Politics: The Origins, Management, and Termination of International Alliances.” In What Do We Know about War? ed. John A. Vasquez, 114–141. Lanham, Md.: Rowman and Littlefield.

    Morgenthau, Hans J., and Kenneth W. Thompson. 1985. Politics among Nations: The Struggle for Power and Peace. 6th ed. New York: Knopf.

    Most, Benjamin, and Randolph Siverson. 1986. “Substituting Arms and Alliances, 1870–1914: An Exploration in Comparative Foreign Policy.” In New Directions in the Study of Foreign Policy, ed. Charles F. Hermann, Charles W. Kegley Jr., and James N. Rosenau, 131–157. Boston: Allen and Unwin.

    Moul, William. 1988. “Great Power Nondefense Alliances and the Escalation to War of Conflicts between Unequals, 1815–1939.” International Interactions 15 (1): 25–43.

    Organski, A. F. K., and Jacek Kugler. 1980. The War Ledger. Chicago: University of Chicago Press.

    Osgood, R. E. 1967. “The Expansion of Force.” In Force, Order, and Justice, ed. R. E. Osgood and R. W. Tucker. Baltimore: Johns Hopkins University Press.

    Parry, Clive. 1978. The Consolidated Treaty Series. Dobb Ferry, N.Y.: Oceana.

    Pogonowski, Iwo Cyprian. 1987. Poland: A Historical Atlas. New York: Hippocrene Books.

    Pribram, Alfred Franzis, Archibald Cary Coolidge, Denys P. Myers, and John Gilman D'Arcy Paul. 1920. The Secret Treaties of Austria-Hungary, 1879–1914. English ed. Cambridge: Harvard University Press.

    Ray, James Lee. 1990. “Friends as Foes: International Conflict and Wars between Formal Allies.” In Prisoners of War? Nation-States in the Modern Era, ed. Charles Gochman and Alan Sabrosky, 73–92. Lexington, Mass.: Lexington Books.

    Ray, James Lee. 1995. Democracy and International Conflict: An Evaluation of the Democratic Peace Proposition. Columbia: University of South Carolina Press.

    Russett, Bruce J., David Singer, and Melvin Small. 1968. “National Political Units in the Twentieth Century: A Standardized List.” American Political Science Review 62: 932–951.

    Sabrosky, Alan Ned. 1985. “Alliance Aggregation, Capability Distribution, and the Expansion of Interstate War.” In Polarity and War, ed. A. Sabrosky, 145–189. Boulder, Colo.: Westview.

    Schroeder, Paul. 1976. “Alliances, 1815–1945: Weapons of Power and Tools of Management.” In Historical Dimensions of National Security Problems, ed. Klaus Knorr, 227–262. Lawrence: University Press of Kansas.

    Singer, J. David, Stuart Bremer, and John Stuckey. 1972. “Capability Distribution, Uncertainty, and Major Power War, 1820–1965.” In Peace, War, and Numbers, ed. B. Russett, 19–48. Beverly Hills, Calif.: Sage.

    Singer, J. David, and Melvin Small. 1966. “Formal Alliances, 1815–1939: A Quantitative Description.” Journal of Peace Research 3, no 1: 1–32.

    Singer, J. David, and Melvin Small. 1968. “Alliance Aggregation and the Onset of War, 1815–1945.” In Quantitative International Politics: Insights and Evidence, ed. J. D. Singer, 247–286. New York: Free Press.

    Singer, J. David, and Melvin Small. 1972. The Wages of War, 1816–1965: A Statistical Handbook. New York: Wiley & Sons.

    Siverson, Randolph, and Joel King. 1979. “Alliances and the Expansion of War.” In To Augur Well, ed. J. David Singer and M. Wallace, 37–49. Beverly Hills, Calif.: Sage.

    Siverson, Randolph, and Joel King. 1980. “Attributes of National Alliance Membership and War Participation, 1815–1965.” American Journal of Political Science 24 (February): 1–15.

    Small, Melvin, and J. D. Singer. 1982. Resort to Arms: International and Civil Wars, 1816–1980. Beverly Hills, Calif.: Sage.

    Vasquez, John. 1993. The War Puzzle. Cambridge: Cambridge University Press.

    Vasquez, John. 1997. “The Realist Paradigm as a Degenerating Research Program: An Appraisal of Neotraditional Research on Waltz's Balancing Proposition.” American Political Science Review 91 (3).

    Wallace, Michael D. 1973. “Alliance Polarization, Cross-Cutting, and International War, 1815–1964.” Journal of Conflict Resolution 17 (December): 575–604.

    Walt, Stephen. 1987. The Origins of Alliances. Ithaca: Cornell University Press.

    Waltz, Kenneth. 1979. Theory of International Politics. Reading, Mass.: Addison-Wesley.

    Ward, Michael D. 1973. Research Gaps in Alliance Dynamics. Vol. 19 of Monograph Series in World Affairs, book 1. Denver: University of Denver.

    Wright, Quincy. 1965. A Study of War. 2d ed. Chicago: University of Chicago Press.

    Yamamoto, Yoshinobu, and Stuart A. Bremer. 1980. “Wider Wars and Restless Nights: Major Power Intervention in Ongoing War.” In The Correlates of War, vol. 2, ed. J. D. Singer, 85–119. New York: Free Press.

    The revisionist fights for a number of reasons (even if its capabilities do not match those of the coalition against it): the adversaries show a lack of resolve, the revisionist state is risk acceptant, or perhaps the revisionist believes a surprise attack could swing the balance of power in its favor.

    Bueno de Mesquita has discounted these findings as a potential level of analysis fallacy, that is, one or two states could be driving the systemic polarization results even though the remaining states in the system are moving away from polarization. Nevertheless, the polarization studies seem to provide evidence that intense polarization is a necessary systemic condition for large-magnitude wars (Vasquez 1993, 248–258). Although polarization is not necessarily associated with the war proneness of single alliances, alliances formed during periods of intense polarization do have an increased chance of being followed by large-magnitude wars. This interpretation is consistent with the findings of Siverson and King (1979) and Sabrosky (1985) on war expansion as well as Organski and Kugler's analysis of world wars (1980, 49–56).

    See Pribram et al. (1920) for a description and terms of the proposed May 6, 1873, treaty with Russia.

    In the few cases where excerpts were unavailable, the summary of the alliance in the secondary sources had to differ in some way. This rule prevents the perpetuation of erroneous reporting through multiple sources.

    For a list of all sources, see Appendix II of Gibler and Sarkees (2004).

    See Gleditsch and Ward (1999) for a discussion and critique of these criteria; however, use of the Gleditsch and Ward coding rules would not greatly alter the composition of the alliance data set. For example, during the years 1816–1944, only five treaties involving ten states had durations that overlapped the Gleditsch and Ward (1999) data but not the Correlates of War system membership data.

    Levy codes the United States as a great power in 1899, but the Correlates of War Project gives it major status in 1898. Likewise, Levy's definition differs by one year compared with Correlates of War for China and Italy (1949 instead of 1950, and 1861 instead of 1860). The only major difference between these two data sets is the coding of Japan. Levy states that Japan achieves great power status in 1905; the Correlates of War project identifies Japan as a major state in 1895.

    Conversations with Jack Levy and historian Paul Schroeder led me to change the major status exit date of Spain from 1808 to 1743. The new date is the last year of Spain's inconclusive war against England and is thought to be a better marker of Spain's exit as a great power (Dupuy and Dupuy 1977, 661).

    Diplomatic recognition was determined through an examination of the historical record. States having extensive contact (for example, exchange of diplomats or dignitaries or treaty agreements) with one of the legitimizers were considered to be formally recognized.

    “Candidate” states were defined as those states that were believed to have the possibility of crossing any of the three inclusion criteria. Among the “states” considered were: Hesse-Cassel, Ireland, Scotland, Romania, Greece, and Bulgaria. Hesse-Cassel never crossed the population threshold. The other states were never fully independent according to the Singer and Small coding rules.

    Singer and Small identify twenty-three states as system members in 1815. At least seven of these twenty-three qualified as major states prior to the 1815 period and are, therefore, considered system members at least from the point at which they achieved major status. Wüurttemberg crossed the population threshold at least by 1759 (extrapolated from two data points fifteen years apart). Baden, Hesse Electoral, and Hesse Grand Ducal were recognized by France and Great Britain by treaty in 1803. The United States was recognized as an independent state by 1784. All other states met both criteria for minor status by 1648.

    The three states of Genoa, Poland, and Venice are included in the pre-1815 data even though Singer and Small omit Genoa and Venice from their lists of system members and include Poland only after 1919. These states met the Singer and Small criteria in periods prior to 1815 but not afterward (that is, they fell from system membership either permanently or for some time). For these three states, the system entry date signifies the date the population threshold was reached (because all had achieved diplomatic recognition). The exit date lists the point at which the state fell to conquerors (Poland) or was incorporated into another state (Genoa and Venice), that is, when the state failed to meet one of the three criteria for system membership.

    Poland also presents a special case for another reason. For most of the period following the War of Polish Succession (1733–1735) to its final dissolution in 1795 (by the Third Partition), Poland was under the limited control of an absentee Saxon king directly influenced by Russia (Pogonowski 1987; Langer 1972). Even though the Polish nobles did not have total control of their foreign policy during this period, the year 1795 remains as the exit date because most foreign policy decisions were still made on Poland's behalf as a separate state. All of the treaties during this period, for example, were made explicitly by “Saxony-Poland.” This period in Poland's history is assumed to be similar to its eventual post–World War II future under communist rule, that is, foreign policy decisions influenced by the Soviet Union but with Poland still a separate state.

    The alliances are always listed according to the date of signature in these volumes. Treaties made by entities that never achieve system membership during the tenure of the treaty are excluded from the Correlates of War data set and are not listed in these volumes.

    Leeds et al. (2002) detail the exact obligations and provisions required for each treaty member according to the alliance treaty. As such, they code treaties that require military cooperation outside the borders of the member states as agreements that carry offensive obligations. Many of these treaties also include provisions for the defense of one or more state in case of attack and are included in the Correlates of War data set as defense pacts. As with the original formal alliance data sets (Singer and Small 1966; Singer and Small 1968), treaties that include only offensive obligations are excluded from this data set.

    How to Use This Book

    These volumes contain the 456 treaties that meet the Correlates of War definition of a formal, interstate alliance signed between the years 1648 and 2008. A summary is included for each alliance as well as the text of the treaty, when available, or a summary of the commitment terms.

    The treaties in this book are arranged as follows: The alliance number and title of each treaty are listed first. The treaties appear in chronological order; numbers are assigned as a locating tool to assist readers. The first digit in the treaty number indicates the chapter in which that treaty appears. The treaty title usually refers to the name given the treaty by the signatories. In cases where no clear title exists, a title that provides some descriptive information is listed.

    The alliance members, signature date and city refer to who signed the treaty and when and where they did so. The date signed often precedes the date the treaty was ratified and the date on which it came into force. In the few cases in which alliances were formed by an exchange of letters between capitals, both cities are included. For each alliance signed between 1816 and 2000, an end date is also included. This represents the estimated date on which the treaty could no longer be considered in force by the signatories. These end dates are often affirmed by the signatories, but in the majority of instances, judgment on the basis of the events taking place during the alliance determined coding of the day the alliance was terminated. Alliances still in force are listed as such. End dates are not included for the 1648–1815 period. Relations between signatories were often too ambiguous to code consistently the exact end dates for these alliances.

    The alliance type is the original Correlates of War designation of alliances: defense pact (Type I), neutrality or non-aggression pact (Type II), or entente (Type III). Exact coding rules for these types are provided in an earlier section of the introduction. Briefly, defense pacts require signatories to come to the aid of their alliance partners, while neutrality pacts require alliance partners to remain militarily neutral should some international crisis occur. Non-aggression pacts are usually pledges by signatories that they will refrain from international acts of violence or that they will stop supporting insurgent groups that target other alliance members. Ententes pledge cooperation and consultation should international crises occur.

    Source includes the citation for the original text of the treaty or for the secondary sources that describe an alliance that is unpublished or for which the complete treaty text is not available in English. For most of the alliances between 1648 and 1918, the original source for documentation is Clive Parry's excellent Consolidated Treaty Series (Dobbs Ferry: Oceana Publications, Inc., various years). For these alliances, the alliance source is cited as Consolidated Treaty Series, volume number, page number. (Thus, “Consolidated Treaty Series, vol. 1, p. 1” refers to a treaty starting on page 1 of Volume 1 of Parry's series.) For treaties signed after World War I and World War II, this title relies on the League of Nations Treaty Series and the United Nations Treaty Series, respectively; these texts are referenced using the source series and the treaty number from that series. For a large minority of treaties, these three large series have been supplemented with source material from other compendiums; in these cases full bibliographic citation to the original text is listed. Finally, some unpublished alliances are coded on the basis of secondary information, including news reports and contemporary histories; for these cases, the source of the description of the terms is provided.

    The summary is a two- to three-paragraph description of the history surrounding the alliance treaty. Why was the alliance formed? Were the terms invoked during conflict? What were the effects of the alliance? For the 1815–2000 alliances, information is included that will allow researchers to determine the cause of alliance termination in the Correlates of War alliance data set.

    Finally, each entry includes the alliance text when an English translation is available. If only excerpts are available, those excerpts are inserted. For all other entries, summaries of key alliance terms are provided.

    Additional notes on language and features:

    Readers will notice that in some older entries, a letter similar to today's letter f is often used in place of the letter s. This reflects the typesetting practices of the time and has been reproduced in this volume. A phrase like “His most Christian Majesty” would be rendered as “His moft Chriftian Majefty” in the transcript in these volumes. Typographical and grammatical errors present in the alliance source documents have been reproduced in these volumes as well.

    In addition to the entries, features have been provided to assist further study. A timeline cataloging major events in political and military history is located at the front of each volume, along with guides listing alliances by region and in chronological order. The shorter general table of contents is further supplemented at the start of each chapter, where readers will find a list of documents within that chapter, effectively adding five century-based tables of contents to the book.

    Timeline of Significant Events

    17th Century

    18th Century

    19th Century

    20th Century

    21st Century

  • Bibliography

    Official Sources

    Australian Treaty Series

    Belgian State Diplomatic Documents

    British and Foreign State Papers

    British State Papers

    Bulgarian State Papers

    Dokumente zur Aussenpolitik der Deutschen Demokratischen Republik [Documents on the foreign policy of the German Democratic Republic]

    French State Papers

    India State Papers

    ITAR-TASS (official news agency of Russia),

    Keesing's Record of World Events. Cambridge, 1931–2008

    League of Arab States,

    League of Nations Treaty Series

    North Atlantic Treaty Organization,

    Parliamentary Papers (Accounts). London. 1816, vol. 17, p. 429

    Peking Review (official publication of Communist Party of China; current title is Beijing Review)

    Recueil des traités de la France [Digest of the treaties of France]. Edited by A. de Clercq. Paris: Amyot, Pedone, 1864–1907.

    Soviet Documents on Foreign Policy. Jane Tabrisky Degras. Oxford: Oxford University Press, 1951.

    Tratados Publicos y Acuerdos Internacionales de Venezuela [Public treaties and international agreements of Venezuela]

    United Nations Treaty Series

    U.S. State Department Documents

    U.S. State Department Bulletins

    Nongovernment and Unofficial Sources

    Consolidated Treaty Series. Edited by Clive Parry. Dobbs Ferry, N.Y.: Oceana Publishing, 1979.

    Danmark-Norges traktater, 1523–1750: med dertil hørende aktstykker [Denmark-Norway treaties, 1523–1750: with related records]. 11 volumes. Copenhagen: G. E. C. Gad, 1907–1949.

    Documents on German Foreign Policy, 1918–1945. Arlington, Va.: Open-Door Press, 1976.

    Documents on International Affairs. Edited by D. C. Watt and John Major et al. London, New York: Oxford University Press for the Royal Institute of International Affairs, 1965.

    European Diplomatic History: Documents and Interpretations, 1815–1914. Edited by Herman N. Weill. New York: Exposition Press, 1972.

    European Treaties Bearing on the History of the United States. Edited by Frances G. Davenport. Washington, D.C.: Carnegie Institution, 1917–1937.

    Founding of the German Empire by William I. Edited by Heinrich von Sybel; translated by Marshall Livingston Perrin and Gamaliel Bradford Jr. New York: T. Y. Crowell & Co., 1890–1891.

    Hertslet's Commercial Treaties. London: Butterworth (vol. 1–19) and H. M. Stationery Office (vol. 20–31), 1840–1925.

    Imperial Russia: A Source Book, 1700–1917. Edited by Basil Dmytryshyn. Gulf Breeze, Fla.: Academic International Press, 1971.

    International Legal Materials. Washington, D.C.: American Society of International Law, 1962–2008.

    Key Treaties for the Great Powers, 1814–1914. Edited by Michael Hurst. New York: St. Martin's Press, 1972.

    Le Relazioni Diplomatiche Fra L'Austria E Il Regno Di Sardegna [Diplomatic relations between Austria and the Kingdom of Sardinia]. Series 2: 1830–1848. Volume 1. Edited by Narciso Nada. Rome: Instituto Storico Italiano Per L'eta Moderna E Contemporanea, 1972.

    Major International Treaties, 1914–1973: History and Guide with Texts. Edited by John Grenville. London: Metheun, 1974.

    Middle East and North Africa in World Politics, A Documentary Record. Edited by Jacob Hurewitz. New Haven: Yale, 1979.

    Nouveau Recueil General De Traites, Conventions Et Autres Transactions Remarquables, Servant A La Connaissance Des Relations Estrangeres Des Puissances Et Etats Dans Leurs Rapports Mutuels: Redige Sur Copies, Collections Et Publications Authentiques [New general digest of treaties, conventions and other important transactions, with foreign powers and states in their mutual relations: written copies, collections and authentic publications]. Series 1. Volume 14, 1843–1852. Edited by G. F. de Martens. Gottingue: Librairie De Dieterich, 1856.

    Österreichische Staatsverträge [Austrian state treaties]. 2 volumes. Edited by Alfred Franzis Pribram. Innsbruck: Wagner'sche Universitäts-Buchhandlung; Vienna: Adolf Holzhausen, 1907–1913.

    Pan-Africanism: A Short Political Guide. Edited by Colin Legum. New York: F. A. Praeger, 1965.

    Readings in European International Relations since 1879. Edited by W. Henry Cooke and Edith P. Stickney. New York: Harper & Bros., 1931.

    Recueil des Traites et Conventions conclus par la Russie avec les Puissances etrangeres [Collection of treaties and conventions concluded by Russia with foreign powers]. 15 volumes. Edited by Fedor F. Martens. St. Petersburg: Ministry of Communications, 1874–1909.

    Recueil des principaux traités d'alliance, de paix, de trêve, etc., conclus par les puissances de l'Europe, tant entre elles qu'avec les puissances et états dans d'autres parties du monde depuis 1761 jusqu’à présent (1801) [Reports of major treaties of alliance, peace, truce, etc., concluded by the powers of Europe, both among themselves and with powers and states in other parts of the world since 1761 until now (1801)]. 7 volumes. Edited by G. F. de Martens. Göttingen: J. C. Dieterich, 1791–1801.

    Survey of International Affairs: The Far East, 1942–1946. Edited by F. C. Jones, Hugh Borton, and B. R. Pearn. London, New York: Oxford University Press, 1955.

Back to Top