International Studies Quarterly (2008)52,737-758 Power or Plenty?Economic Interests, Security Concerns,and American Intervention BENJAMIN O.FORDHAM Binghamton University (SUNY) This paper evaluates the effect of economic interests and security con- cerns on American intervention in civil and international conflict.Gener- alizations about the relative importance of these considerations have played critical role in the historiography of American foreign relations. Although statistical analysis is well suited for evaluating such generaliza- tions,quantitative researchers have devoted relatively little attention to the issue.Existing large-n research has generally found that security con- cerns matter more.but has not considered how the economic and secu- rity concerns thought to affect intervention might also influence each other.These subsidiary relationships complicate efforts to assess the rela- tive importance of these two influences on intervention.Evidence con- cerning intervention in international crises and civil wars indicates that, while alliance commitments and rival behavior have a greater immediate impact on American intervention,exports have an important indirect effect by shaping alliance commitments in the long run. The Correlates of War Project records 2,007 disputes between states during the 20th century,129 of which escalated to war.There were also 35 wars between states and non-state entities outside their borders as well as 141 civil wars.Over the same period,there were also many other incidents of violence that were con- sequential for world politics but not recorded in the most frequently used data sets.In spite of the fact that the American role in world politics steadily expanded over the course of the century,the United States intervened in rela- tively few of these international conflicts.What explains American decisions about whether or not to become involved? This is one of the most important questions facing scholars of American for- eign policy.Answers illuminate policy makers'perceptions of national interest, and may thus help explain decisions about a wider range of foreign policy ques- tions.This article will focus on the relationship between two of the most impor- tant sources of explanation for American intervention:security concerns and economic interests.Although economic and security concerns are often posed as competing alternatives,most observers would probably concede that both matter. The question here is what role each plays in the process leading to intervention. Author's note:I would like to thank Michelle Benson,David H.Clark,Michael Colaresi,Patrick Regan,Elizabeth Saunders,and participants in the World Politics workshop at Binghamton University for their comments and sug gestions on carlier versions of this paper,as well as Viner (1948)for assistance with the title of this work.Any remaining errors are my responsibility.The data used in this article can be obtained from the author at(http:// bingweb.binghamton.edu/-bfordham/),or from the International Studies Quarterly Dataverse Network page at (http://dvn.iq.harvard.edu/dvn/). 2008 Intemational Studies Association
Power or Plenty? Economic Interests, Security Concerns, and American Intervention Benjamin O. Fordham Binghamton University (SUNY) This paper evaluates the effect of economic interests and security concerns on American intervention in civil and international conflict. Generalizations about the relative importance of these considerations have played critical role in the historiography of American foreign relations. Although statistical analysis is well suited for evaluating such generalizations, quantitative researchers have devoted relatively little attention to the issue. Existing large-n research has generally found that security concerns matter more, but has not considered how the economic and security concerns thought to affect intervention might also influence each other. These subsidiary relationships complicate efforts to assess the relative importance of these two influences on intervention. Evidence concerning intervention in international crises and civil wars indicates that, while alliance commitments and rival behavior have a greater immediate impact on American intervention, exports have an important indirect effect by shaping alliance commitments in the long run. The Correlates of War Project records 2,007 disputes between states during the 20th century, 129 of which escalated to war. There were also 35 wars between states and non-state entities outside their borders as well as 141 civil wars. Over the same period, there were also many other incidents of violence that were consequential for world politics but not recorded in the most frequently used data sets. In spite of the fact that the American role in world politics steadily expanded over the course of the century, the United States intervened in relatively few of these international conflicts. What explains American decisions about whether or not to become involved? This is one of the most important questions facing scholars of American foreign policy. Answers illuminate policy makers’ perceptions of national interest, and may thus help explain decisions about a wider range of foreign policy questions. This article will focus on the relationship between two of the most important sources of explanation for American intervention: security concerns and economic interests. Although economic and security concerns are often posed as competing alternatives, most observers would probably concede that both matter. The question here is what role each plays in the process leading to intervention. Author’s note: I would like to thank Michelle Benson, David H. Clark, Michael Colaresi, Patrick Regan, Elizabeth Saunders, and participants in the World Politics workshop at Binghamton University for their comments and suggestions on earlier versions of this paper, as well as Viner (1948) for assistance with the title of this work. Any remaining errors are my responsibility. The data used in this article can be obtained from the author at (http:// bingweb.binghamton.edu/~bfordham/), or from the International Studies Quarterly Dataverse Network page at (http://dvn.iq.harvard.edu/dvn/). 2008 International Studies Association International Studies Quarterly (2008) 52, 737–758
738 Power or Plenty? The evidence considered here suggests that security concerns about the welfare of allies and the actions of rivals have a greater immediate impact on interven- tion decisions,but that economic interests also have important long-run indirect effects by shaping the things that get defined as security interests.The United States has been more likely to extend security guarantees to important trading partners than to less economically significant states.The process this evidence implies is one in which intervention decisions are made on the basis of security concerns rather than economic interests,just as decision makers typically claim they do.However,economic relationships shape these security interests over long periods of time in ways that may escape the attention of decision makers preoccu- pied with ongoing events. This article proceeds in four parts.The first reviews debates among historians and political scientists about the role of economic and security concerns in American foreign policy.The second sets out a research design for testing the influence of these two sources of explanation as well as the relationship between them.The third section presents the empirical results.A final section summa- rizes and concludes. Economic and Security Interests in Intervention Decisions What is the role of economic and security concerns in American decisions about intervention?Surprisingly,this question has received much greater attention from historians,who are typically less concerned about such broad patterns across space and time,than from political scientists,for whom such patterns are a central preoccupation.This section will first examine the way these two sets of researchers have addressed this question,then consider how each fits into the causal process leading to intervention. Historians,Political Scientists,and the Role of Economic and Security Concerns The relative importance of economic interests and security concerns has been a major bone of contention among historians of American foreign relations.Con- troversies among historians have generally focused on specific historical cases, but they also reflect broader theoretical differences about the forces that have shaped American foreign policy priorities.A political scientist (though probably not a historian)would say that these controversies concern competing models of the policymaking process.The debate over these models has often had an ideo- logical edge because of what they suggest about whose interests American for- eign policy has typically served.As the historian Emily Rosenberg(1993,37)has put it,"interpretations that stressed economics tended to be joined to radical critiques of American foreign policy and of America itself."Efforts to protect economic interests nearly always generate winners and losers in American society, while security is a public good that all Americans can enjoy. Models of the policy-making process play a different role in historical accounts of American foreign policy than in most political science research.Political scien- tists typically begin with an explicit model and then seek to test it empirically.By contrast,historians usually present a narrative account of the specific historical process that interests them without an explicit model.These narratives often incorporate material that is not relevant to a social-scientific test of the theoreti- cal model implicit in the work but that provides greater descriptive detail about what actually happened.The fact that historians'theoretical models of the for- eign policy process are implicit does not mean they are unimportant.Some theo- retical account of the underlying historical process is necessary to suggest relevant sources for research,to make connections among disparate pieces of evidence,and to fill in the gaps where the sources are silent
The evidence considered here suggests that security concerns about the welfare of allies and the actions of rivals have a greater immediate impact on intervention decisions, but that economic interests also have important long-run indirect effects by shaping the things that get defined as security interests. The United States has been more likely to extend security guarantees to important trading partners than to less economically significant states. The process this evidence implies is one in which intervention decisions are made on the basis of security concerns rather than economic interests, just as decision makers typically claim they do. However, economic relationships shape these security interests over long periods of time in ways that may escape the attention of decision makers preoccupied with ongoing events. This article proceeds in four parts. The first reviews debates among historians and political scientists about the role of economic and security concerns in American foreign policy. The second sets out a research design for testing the influence of these two sources of explanation as well as the relationship between them. The third section presents the empirical results. A final section summarizes and concludes. Economic and Security Interests in Intervention Decisions What is the role of economic and security concerns in American decisions about intervention? Surprisingly, this question has received much greater attention from historians, who are typically less concerned about such broad patterns across space and time, than from political scientists, for whom such patterns are a central preoccupation. This section will first examine the way these two sets of researchers have addressed this question, then consider how each fits into the causal process leading to intervention. Historians, Political Scientists, and the Role of Economic and Security Concerns The relative importance of economic interests and security concerns has been a major bone of contention among historians of American foreign relations. Controversies among historians have generally focused on specific historical cases, but they also reflect broader theoretical differences about the forces that have shaped American foreign policy priorities. A political scientist (though probably not a historian) would say that these controversies concern competing models of the policymaking process. The debate over these models has often had an ideological edge because of what they suggest about whose interests American foreign policy has typically served. As the historian Emily Rosenberg (1993, 37) has put it, ‘‘interpretations that stressed economics tended to be joined to radical critiques of American foreign policy and of America itself.’’ Efforts to protect economic interests nearly always generate winners and losers in American society, while security is a public good that all Americans can enjoy. Models of the policy-making process play a different role in historical accounts of American foreign policy than in most political science research. Political scientists typically begin with an explicit model and then seek to test it empirically. By contrast, historians usually present a narrative account of the specific historical process that interests them without an explicit model. These narratives often incorporate material that is not relevant to a social-scientific test of the theoretical model implicit in the work but that provides greater descriptive detail about what actually happened. The fact that historians’ theoretical models of the foreign policy process are implicit does not mean they are unimportant. Some theoretical account of the underlying historical process is necessary to suggest relevant sources for research, to make connections among disparate pieces of evidence, and to fill in the gaps where the sources are silent. 738 Power or Plenty?
BENJAMIN O.FORDHAM 739 The model implied by historians who stress security concerns strongly resem- bles the one commonly advanced by realists in the international relations litera- ture.It suggests a plausible narrative of the way American policy makers have made decisions about intervention.American leaders,like the leaders of all states,must ensure the physical safety of Americans from foreign attack as well as the political sovereignty and territorial integrity of the American state in a condi- tion of international anarchy.This task has always been far easier than that con- fronting the leaders of states not fortunate enough to be surrounded by large oceans and weaker neighbors.For most of American history,these circumstances provided Americans with what Woodward(1960)aptly labeled "free security." As technology eroded the defensive value of the Atlantic and Pacific Oceans dur- ing the 20th century,American policy makers were forced to adopt a more activ- ist foreign policy in order to provide the same level of security.Entanglement in war and conflict in Europe and Asia became more difficult to avoid,and eventu- ally the United States found itself playing a leading role in alliance systems and other security arrangements all over the globe.Narratives informed by this broad understanding of American foreign policy tend to focus on policy makers'evolv- ing perceptions of international conditions. Historians stressing the importance of economic interests in shaping American foreign policy begin with a different argument about the priorities of American leaders.They treat American leaders'claims about national security skeptically. The best policy for insuring American security has been unclear and highly con- tested in important historical cases.For this reason,security concerns provide a weak basis for explaining American choices about intervention.These historians focus instead on the interests of the political coalitions backing particular Ameri- can leaders,constructing an alternative explanation for the increasing global activism of the United States during the 20th century.Broadly summarized,the story is that the American economy led to increasing demands for the protection of important overseas trading partners and investment sites,and a concomitant increase in the capacity of the American state to satisfy these demands.Historical narratives arising from this perspective tend to explain policy in terms of politi- cal conflict among domestic factions with competing interests. Even though theoretical arguments about the role of economic and security concerns are rarely stated explicitly,their influence is not difficult to discern in the historiography of American foreign relations.During the 1920s and 1930s,the debate over the reasons for American intervention in World War I turned on the question of economic motives (Cohen 1967;Fordham 2007)."Revisionist''histori- ans rejected the Wilson administration's reasons for American entry,arguing instead that the large American stake in wartime exports to the Allied powers heav- ily influenced the decision to intervene on their side in 1917 (e.g.,Beard 1936; Grattan 1929;Tansill 1938).The economic importance of this trade led the Wilson administration to take a hard line on German submarine warfare.This hard line ultimately led to intervention.Many other historians rejected the revisionist claim about the role of economic interests.They argued instead that security considerations-including anger over American loss of life due to the sub- marine campaign,fears about the consequences of a German victory,and national prestige were largely independent of trade with the Allies and played a more important role in the decision to intervene (e.g.,May 1959;Seymour [1935]1967; Smith 1965).The approach of World War II politicized this debate.Advocates of non-intervention adopted many elements of the revisionist argument in their suc- cessful legislative effort to restrict trade and lending to belligerent states.Many prominent revisionist historians,such as Charles Beard,supported them. After World War II,a new,more general controversy arose over the role of economic interests in American intervention.William A.Williams (1959)influen- tially argued that the demands of commercial expansion had driven American
The model implied by historians who stress security concerns strongly resembles the one commonly advanced by realists in the international relations literature. It suggests a plausible narrative of the way American policy makers have made decisions about intervention. American leaders, like the leaders of all states, must ensure the physical safety of Americans from foreign attack as well as the political sovereignty and territorial integrity of the American state in a condition of international anarchy. This task has always been far easier than that confronting the leaders of states not fortunate enough to be surrounded by large oceans and weaker neighbors. For most of American history, these circumstances provided Americans with what Woodward (1960) aptly labeled ‘‘free security.’’ As technology eroded the defensive value of the Atlantic and Pacific Oceans during the 20th century, American policy makers were forced to adopt a more activist foreign policy in order to provide the same level of security. Entanglement in war and conflict in Europe and Asia became more difficult to avoid, and eventually the United States found itself playing a leading role in alliance systems and other security arrangements all over the globe. Narratives informed by this broad understanding of American foreign policy tend to focus on policy makers’ evolving perceptions of international conditions. Historians stressing the importance of economic interests in shaping American foreign policy begin with a different argument about the priorities of American leaders. They treat American leaders’ claims about national security skeptically. The best policy for insuring American security has been unclear and highly contested in important historical cases. For this reason, security concerns provide a weak basis for explaining American choices about intervention. These historians focus instead on the interests of the political coalitions backing particular American leaders, constructing an alternative explanation for the increasing global activism of the United States during the 20th century. Broadly summarized, the story is that the American economy led to increasing demands for the protection of important overseas trading partners and investment sites, and a concomitant increase in the capacity of the American state to satisfy these demands. Historical narratives arising from this perspective tend to explain policy in terms of political conflict among domestic factions with competing interests. Even though theoretical arguments about the role of economic and security concerns are rarely stated explicitly, their influence is not difficult to discern in the historiography of American foreign relations. During the 1920s and 1930s, the debate over the reasons for American intervention in World War I turned on the question of economic motives (Cohen 1967; Fordham 2007). ‘‘Revisionist’’ historians rejected the Wilson administration’s reasons for American entry, arguing instead that the large American stake in wartime exports to the Allied powers heavily influenced the decision to intervene on their side in 1917 (e.g., Beard 1936; Grattan 1929; Tansill 1938). The economic importance of this trade led the Wilson administration to take a hard line on German submarine warfare. This hard line ultimately led to intervention. Many other historians rejected the revisionist claim about the role of economic interests. They argued instead that security considerations—including anger over American loss of life due to the submarine campaign, fears about the consequences of a German victory, and national prestige were largely independent of trade with the Allies and played a more important role in the decision to intervene (e.g., May 1959; Seymour [1935] 1967; Smith 1965). The approach of World War II politicized this debate. Advocates of non-intervention adopted many elements of the revisionist argument in their successful legislative effort to restrict trade and lending to belligerent states. Many prominent revisionist historians, such as Charles Beard, supported them. After World War II, a new, more general controversy arose over the role of economic interests in American intervention. William A. Williams (1959) influentially argued that the demands of commercial expansion had driven American Benjamin O. Fordham 739
740 Power or Plenty? involvement in less developed areas of the world since the 1890s.Other histori- cal accounts of American foreign policy followed Williams'example,stressing the role of economic interests in spurring the overseas activity of the American state (e.g.,LaFeber 1963;McCormick 1967).This group of historians-also commonly referred to as "revisionists,"although few discussed American involvement in World War I-were also skeptical of the Cold War security concerns offered to justify most postwar interventions (e.g.,Kolko and Kolko 1972;LaFeber1967). Many other historians objected to interpretations stressing economic interests, offering accounts that emphasized security concerns over the spread of Soviet power.They held that the revisionists were unduly critical of American policy makers'motives,and that the security concerns these policy makers had cited were not mere window-dressing for underlying economic interests (e.g.,Gaddis 1972;Tucker 1971).As had been the case with interpretations of American inter- vention in World War I,the scholarly debate's resonance with contemporary policy issues-in this case,the Vietnam War-politicized it.Historiographical controversy over the role of economic and security concerns in Cold War foreign policy did not entirely lose its political edge even after the Cold War came to an end (e.g.,Cumings 1993;Gaddis 1996;Schrecker 2004). Political scientists are typically more interested in theoretical generalization than are historians,so it is somewhat surprising that the relative importance of economic and security concerns in American intervention has received less atten- tion from them.Case study research that most resembles (and often relies upon) the work of historians has paid the most attention to the issue.The divergent conclusions about the role of economic interests mirror those found among historians.While some have presented evidence that these interests have played a crucial role in some intervention decisions (e.g.,Cox 1994;Gibbs 1990; McKeown 2000),others accord greater importance to security concerns derived from state decision makers'conceptions of the national interest (e.g.,Krasner 1978;Lake1988). The relative importance of economic and security interests in American for- eign policy has received much less attention from quantitative researchers.What there is tends to support the importance of security concerns relative to eco- nomic interests.Some early studies found evidence that economic interests influ- enced decisions about intervention (e.g.,Odell 1974;Rosen 1974).However, subsequent work has generally found greater support for security concerns than for economic interests (e.g.,Meernik 1994;Pearson and Baumann 1977;Yoon 1997).Perhaps reflecting these findings,the considerable body of recent research on civil war intervention has set economic concerns aside and focused on other explanations for intervention,such as the nature of the conflict or stra- tegic interaction among potential interveners (e.g.,Findley and Teo 2006;Regan 1998,2000).Indeed,most recent quantitative analyses of intervention do not include economic variables at all. The neglect of the question of economic and security interests in quantitative research on intervention is unfortunate.This approach is especially well suited for answering questions about the relative importance of these concerns across large numbers of historical cases.These are precisely the kinds of generalizations that have sparked so much controversy among historians of American foreign relations.Even though most scholars engaged in quantitative empirical research understandably prefer to study theoretical arguments that apply to more than just the U.S.case,patterns confined to smaller slices of space and time still deserve attention.Given the nation's enormous role in the contemporary world, understanding the sources of American behavior is not simply a parochial con- cern.A more general explanation also accounting for the behavior of many other states might be preferable,but is not available.In its absence,testing more
involvement in less developed areas of the world since the 1890s. Other historical accounts of American foreign policy followed Williams’ example, stressing the role of economic interests in spurring the overseas activity of the American state (e.g., LaFeber 1963; McCormick 1967). This group of historians—also commonly referred to as ‘‘revisionists,’’ although few discussed American involvement in World War I—were also skeptical of the Cold War security concerns offered to justify most postwar interventions (e.g., Kolko and Kolko 1972; LaFeber 1967). Many other historians objected to interpretations stressing economic interests, offering accounts that emphasized security concerns over the spread of Soviet power. They held that the revisionists were unduly critical of American policy makers’ motives, and that the security concerns these policy makers had cited were not mere window-dressing for underlying economic interests (e.g., Gaddis 1972; Tucker 1971). As had been the case with interpretations of American intervention in World War I, the scholarly debate’s resonance with contemporary policy issues—in this case, the Vietnam War—politicized it. Historiographical controversy over the role of economic and security concerns in Cold War foreign policy did not entirely lose its political edge even after the Cold War came to an end (e.g., Cumings 1993; Gaddis 1996; Schrecker 2004). Political scientists are typically more interested in theoretical generalization than are historians, so it is somewhat surprising that the relative importance of economic and security concerns in American intervention has received less attention from them. Case study research that most resembles (and often relies upon) the work of historians has paid the most attention to the issue. The divergent conclusions about the role of economic interests mirror those found among historians. While some have presented evidence that these interests have played a crucial role in some intervention decisions (e.g., Cox 1994; Gibbs 1990; McKeown 2000), others accord greater importance to security concerns derived from state decision makers’ conceptions of the national interest (e.g., Krasner 1978; Lake 1988). The relative importance of economic and security interests in American foreign policy has received much less attention from quantitative researchers. What there is tends to support the importance of security concerns relative to economic interests. Some early studies found evidence that economic interests influenced decisions about intervention (e.g., Odell 1974; Rosen 1974). However, subsequent work has generally found greater support for security concerns than for economic interests (e.g., Meernik 1994; Pearson and Baumann 1977; Yoon 1997). Perhaps reflecting these findings, the considerable body of recent research on civil war intervention has set economic concerns aside and focused on other explanations for intervention, such as the nature of the conflict or strategic interaction among potential interveners (e.g., Findley and Teo 2006; Regan 1998, 2000). Indeed, most recent quantitative analyses of intervention do not include economic variables at all. The neglect of the question of economic and security interests in quantitative research on intervention is unfortunate. This approach is especially well suited for answering questions about the relative importance of these concerns across large numbers of historical cases. These are precisely the kinds of generalizations that have sparked so much controversy among historians of American foreign relations. Even though most scholars engaged in quantitative empirical research understandably prefer to study theoretical arguments that apply to more than just the U.S. case, patterns confined to smaller slices of space and time still deserve attention. Given the nation’s enormous role in the contemporary world, understanding the sources of American behavior is not simply a parochial concern. A more general explanation also accounting for the behavior of many other states might be preferable, but is not available. In its absence, testing more 740 Power or Plenty?
BENJAMIN O.FORDHAM 741 limited theoretical generalizations is useful,especially when doing so can advance a debate in such a closely allied field of study. Thinking Through the Role of Economic and Security Interests One of the striking features of the debate over the relative importance of eco- nomic interests and security concerns is that scholars rarely argue that either set of considerations is entirely irrelevant to policy choice.Even those who strongly emphasize one source of explanation over the other usually acknowledge that many factors contributed to intervention decisions.For example,in spite of the stark differences between revisionist historians of American intervention in World War I and their critics,members of both camps commonly acknowledged the influence of security concerns as well as economic interests in their narra- tives (Fordham 2007,283-84).For most scholars,interpreting the role of eco- nomic and security concerns is a matter of emphasis. The likelihood that both considerations may make a difference complicates efforts to explain intervention in ways that are not always appreciated in the exist- ing research.Most efforts to assess the relative importance of economic and secu- rity concerns have implicitly assumed that these two sources of explanation do not cause one another.This assumption is clearest in the quantitative political sci- ence literature,where the most common approach has been to regress decisions about intervention on indicators of economic and security concerns without pay- ing much attention to the relationships among the independent variables.The assumption is less visible but equally important in qualitative research on inter- vention.Historical researchers usually focus on archival evidence concerning the decision-making process.The assumption that economic and security concerns are independent justifies the inference that,when security concerns dominate policy deliberations,economic interests are relatively unimportant. There are good reasons to suppose that security concerns and economic inter- ests are not causally unrelated,however.Economic interests may help define security concerns,or security-motivated polices could shape economic interests. The fact that the relationship might run in either direction is crucial for assess- ing the relative importance of these two sets of concerns and for discerning their roles in the causal process.Previous research has found evidence that bilateral trade is greater among allies (Gowa and Mansfield 1993,2004;Long 2003;Mans- field and Bronson 1997).Gowa and Mansfield(1993)argue that trade generates security externalities by strengthening the economies,and thus the military potential,of the states involved.They suggest that states seek to manipulate these externalities by encouraging trade with their allies and limiting it with their potential enemies.If trade indeed follows the flag in this way,then part of trade's apparent effect on intervention decisions would really be due to the indi- rect influence of the security commitments on trading patterns. On the other hand,the causal arrow might point in the opposite direction: strong trade relations or other economic interests might make the formation of an alliance more likely.Policy makers should care about the security of economi- cally important markets or sites for investment because the benefits they draw from these economic relationships depend on it.This line of argument follows from liberal claims about the conflict-reducing effects of international commerce on trading partners (e.g.,Oneal and Russett 1997;Polachek 1980).The source of this effect is state leaders'concern about the loss of income to their citizens due to conflict's disruptive effects on trade.The same logic suggests that,to the extent that income from trade depends on the security and stability of a state's trading partners,states should be more likely to make costly commitments to assist those states.Major powers like the United States are especially likely to pro- tect their trading partners because they have the capacity to do so,something
limited theoretical generalizations is useful, especially when doing so can advance a debate in such a closely allied field of study. Thinking Through the Role of Economic and Security Interests One of the striking features of the debate over the relative importance of economic interests and security concerns is that scholars rarely argue that either set of considerations is entirely irrelevant to policy choice. Even those who strongly emphasize one source of explanation over the other usually acknowledge that many factors contributed to intervention decisions. For example, in spite of the stark differences between revisionist historians of American intervention in World War I and their critics, members of both camps commonly acknowledged the influence of security concerns as well as economic interests in their narratives (Fordham 2007, 283–84). For most scholars, interpreting the role of economic and security concerns is a matter of emphasis. The likelihood that both considerations may make a difference complicates efforts to explain intervention in ways that are not always appreciated in the existing research. Most efforts to assess the relative importance of economic and security concerns have implicitly assumed that these two sources of explanation do not cause one another. This assumption is clearest in the quantitative political science literature, where the most common approach has been to regress decisions about intervention on indicators of economic and security concerns without paying much attention to the relationships among the independent variables. The assumption is less visible but equally important in qualitative research on intervention. Historical researchers usually focus on archival evidence concerning the decision-making process. The assumption that economic and security concerns are independent justifies the inference that, when security concerns dominate policy deliberations, economic interests are relatively unimportant. There are good reasons to suppose that security concerns and economic interests are not causally unrelated, however. Economic interests may help define security concerns, or security-motivated polices could shape economic interests. The fact that the relationship might run in either direction is crucial for assessing the relative importance of these two sets of concerns and for discerning their roles in the causal process. Previous research has found evidence that bilateral trade is greater among allies (Gowa and Mansfield 1993, 2004; Long 2003; Mans- field and Bronson 1997). Gowa and Mansfield (1993) argue that trade generates security externalities by strengthening the economies, and thus the military potential, of the states involved. They suggest that states seek to manipulate these externalities by encouraging trade with their allies and limiting it with their potential enemies. If trade indeed follows the flag in this way, then part of trade’s apparent effect on intervention decisions would really be due to the indirect influence of the security commitments on trading patterns. On the other hand, the causal arrow might point in the opposite direction: strong trade relations or other economic interests might make the formation of an alliance more likely. Policy makers should care about the security of economically important markets or sites for investment because the benefits they draw from these economic relationships depend on it. This line of argument follows from liberal claims about the conflict-reducing effects of international commerce on trading partners (e.g., Oneal and Russett 1997; Polachek 1980). The source of this effect is state leaders’ concern about the loss of income to their citizens due to conflict’s disruptive effects on trade. The same logic suggests that, to the extent that income from trade depends on the security and stability of a state’s trading partners, states should be more likely to make costly commitments to assist those states. Major powers like the United States are especially likely to protect their trading partners because they have the capacity to do so, something Benjamin O. Fordham 741
742 Power or Plenty? not every state possesses.For example,the need to ensure continuing access to the region's oil resources might help explain current American security commit- ments in the Persian Gulf region. Historians of American foreign relations who emphasize the role of economic interests also suggest that the protection of important markets has sometimes led to American security commitments.For example,Hogan (1987,192)argues that the formation of the North Atlantic Treaty Organization was closely linked to efforts to bring about economic recovery in Western Europe and to integrate it into the international economic order American policy makers favored.Similarly, McGlothlen (1993)and Rotter (1987)link American security commitments in Asia to the effort to promote the recovery and integration of Japan.If arguments like these are correct,then part of the apparent effect of alliances on decisions about intervention is actually due to economic interests because these prompted the security commitment in the first place. The potential indirect effect of alliances through trade,and of trade through alliances,makes the magnitude and direction of the trade-alliance relationship important for assessing the effects of economic and security concerns on inter- vention.A single-equation model treating intervention as a function of all these variables together will not capture the indirect effects.A model that considers the potential indirect effects of these variables also suggests a different type of answer to the question of whether economic or security concerns are more important.Instead of emphasizing one or indicating that both influence policy makers in the same way,it holds out the possibility that the two considerations influence different stages of the policy-making process.The next section will present a research design for estimating these effects. Testing the Influence of Economic and Security Interests This section outlines a strategy for testing the role of economic and security con- cerns in various stages of the process leading to intervention.Figure 1 sets out the relationships that will be considered.The first stage of the test is to evaluate the direct effects of economic and security concerns on intervention decisions under certain circumstances.The causal paths of interest in this stage correspond to the arrows pointing to"U.S.Intervention'in the Figure.For the reasons discussed in the last section,concluding the analysis at this point,as previous quantitative analy- ses have done,neglects the important possibility that trade may influence interven- tion by shaping alliances,or vice versa.In order to capture this effect,the next step is to sort out the effects of trade and alliances on one another.Once this has been done,it is possible to estimate the total effect of the independent variables on intervention.The end result is a more realistic test of the relative importance of Economic Interests Rival Intervention U.S.Intervention Alliance commitment FIG.1.Influences on Intervention Decisions
not every state possesses. For example, the need to ensure continuing access to the region’s oil resources might help explain current American security commitments in the Persian Gulf region. Historians of American foreign relations who emphasize the role of economic interests also suggest that the protection of important markets has sometimes led to American security commitments. For example, Hogan (1987, 192) argues that the formation of the North Atlantic Treaty Organization was closely linked to efforts to bring about economic recovery in Western Europe and to integrate it into the international economic order American policy makers favored. Similarly, McGlothlen (1993) and Rotter (1987) link American security commitments in Asia to the effort to promote the recovery and integration of Japan. If arguments like these are correct, then part of the apparent effect of alliances on decisions about intervention is actually due to economic interests because these prompted the security commitment in the first place. The potential indirect effect of alliances through trade, and of trade through alliances, makes the magnitude and direction of the trade-alliance relationship important for assessing the effects of economic and security concerns on intervention. A single-equation model treating intervention as a function of all these variables together will not capture the indirect effects. A model that considers the potential indirect effects of these variables also suggests a different type of answer to the question of whether economic or security concerns are more important. Instead of emphasizing one or indicating that both influence policy makers in the same way, it holds out the possibility that the two considerations influence different stages of the policy-making process. The next section will present a research design for estimating these effects. Testing the Influence of Economic and Security Interests This section outlines a strategy for testing the role of economic and security concerns in various stages of the process leading to intervention. Figure 1 sets out the relationships that will be considered. The first stage of the test is to evaluate the direct effects of economic and security concerns on intervention decisions under certain circumstances. The causal paths of interest in this stage correspond to the arrows pointing to ‘‘U.S. Intervention’’ in the Figure. For the reasons discussed in the last section, concluding the analysis at this point, as previous quantitative analyses have done, neglects the important possibility that trade may influence intervention by shaping alliances, or vice versa. In order to capture this effect, the next step is to sort out the effects of trade and alliances on one another. Once this has been done, it is possible to estimate the total effect of the independent variables on intervention. The end result is a more realistic test of the relative importance of Fig. 1. Influences on Intervention Decisions 742 Power or Plenty?
BENJAMIN O.FORDHAM 743 economic and security concerns on intervention and a more complete account of where each fits into the causal process Testing the effects of economic and security concerns in this way requires solu- tions to two research design problems.First,data on incidents in which Ameri- can intervention was a possibility must be gathered.Because arguments about the role of economic and security concerns apply to many classes of events,I will examine data on both civil wars and international crises.Second,economic and security concerns must be operationalized in realistic ways.I will use data on the behavior of rival states,alliance commitments,and American exports.The remainder of this section will explain these research design choices. Opportunities for Intervention:Civil Wars and International Crises Testing the influence of economic and security concerns on intervention requires data on incidents where intervention was a possibility.In principle, intervention requires no triggering event.States can and do use force without provocation.For research purposes,however,it is useful to begin with a class of events that has sometimes precipitated intervention.Arguments about economic and security interests can then be tested by estimating the influence of observa- ble indicators of these concerns on the probability of intervention within this class of events.I will consider two such classes of events here:civil wars and inter- national crises. Civil wars are a useful setting in which to consider the determinants of inter- vention.Given the potential costs involved,decision makers cannot undertake these interventions lightly.On the other hand,if policy makers believe that con- ditions in the affected states are important,then civil wars are difficult to ignore. Data on civil wars are relatively abundant,but information on intervention in these conflicts is not.Policy makers may decide the stakes in a particular conflict are important,yet use economic or military aid rather than committing their armed forces.The central question here concerns what makes particular civil wars sufficiently important to draw serious American attention,even if they do not involve direct military action.Thus it makes sense to look at intervention more broadly than just the use of force.Unfortunately,military action is the only type of intervention coded in many existing data sets.Patrick Regan's (2000, 2002)data set on civil wars is an exception,containing information about several forms of intervention.Including the provision of economic and military aid,the United States intervened in 38 of the 150 civil wars included in Regan's data, which cover the 1944-99 period. Although interstate conflicts differ from civil wars in many important respects, scholars have made many of the same arguments about economic and security concerns motivating intervention in both.Examining intervention in interna- tional crises complements the analysis of civil war intervention,ensuring that the patterns identified are not unique to that class of conflict events.The Inter- national Crisis Behavior (ICB)project has identified 435 international crises 1A third research design issue concerns the possibility of selection bias in the samples of civil wars and intema- tional crises considered here.Selection bias would be an important issue if American trade or alliance commit- ments influenced the probability that a crisis or civil war broke out in the first place.For example,if credible American alliance commitments always deterred potential challengers from threatening American allies,or per- suaded potential rebels that their cause was hopeless,then crises and civil wars would only be observed when Ameri- can alliance commitments were not credible.The sample of observed crises and civil wars would contain only cases where the American alliance commitment was shaky,perhaps leading to the conclusion that alliance commitments were not strongly associated with subsequent American intervention on behalf of its endangered allies.Although this is an important problem in principle,censored probit selection models designed to handle it turned up little evidence that it made an important difference in practice.The rho parameter was not significantly different from zero,and coefficient estimates were nearly identical to those presented in the next section.A more thorough pre- sentation of these models can be found in the online appendix posted with the replication data
economic and security concerns on intervention and a more complete account of where each fits into the causal process. Testing the effects of economic and security concerns in this way requires solutions to two research design problems. First, data on incidents in which American intervention was a possibility must be gathered. Because arguments about the role of economic and security concerns apply to many classes of events, I will examine data on both civil wars and international crises. Second, economic and security concerns must be operationalized in realistic ways. I will use data on the behavior of rival states, alliance commitments, and American exports. The remainder of this section will explain these research design choices.1 Opportunities for Intervention: Civil Wars and International Crises Testing the influence of economic and security concerns on intervention requires data on incidents where intervention was a possibility. In principle, intervention requires no triggering event. States can and do use force without provocation. For research purposes, however, it is useful to begin with a class of events that has sometimes precipitated intervention. Arguments about economic and security interests can then be tested by estimating the influence of observable indicators of these concerns on the probability of intervention within this class of events. I will consider two such classes of events here: civil wars and international crises. Civil wars are a useful setting in which to consider the determinants of intervention. Given the potential costs involved, decision makers cannot undertake these interventions lightly. On the other hand, if policy makers believe that conditions in the affected states are important, then civil wars are difficult to ignore. Data on civil wars are relatively abundant, but information on intervention in these conflicts is not. Policy makers may decide the stakes in a particular conflict are important, yet use economic or military aid rather than committing their armed forces. The central question here concerns what makes particular civil wars sufficiently important to draw serious American attention, even if they do not involve direct military action. Thus it makes sense to look at intervention more broadly than just the use of force. Unfortunately, military action is the only type of intervention coded in many existing data sets. Patrick Regan’s (2000, 2002) data set on civil wars is an exception, containing information about several forms of intervention. Including the provision of economic and military aid, the United States intervened in 38 of the 150 civil wars included in Regan’s data, which cover the 1944–99 period. Although interstate conflicts differ from civil wars in many important respects, scholars have made many of the same arguments about economic and security concerns motivating intervention in both. Examining intervention in international crises complements the analysis of civil war intervention, ensuring that the patterns identified are not unique to that class of conflict events. The International Crisis Behavior (ICB) project has identified 435 international crises 1 A third research design issue concerns the possibility of selection bias in the samples of civil wars and international crises considered here. Selection bias would be an important issue if American trade or alliance commitments influenced the probability that a crisis or civil war broke out in the first place. For example, if credible American alliance commitments always deterred potential challengers from threatening American allies, or persuaded potential rebels that their cause was hopeless, then crises and civil wars would only be observed when American alliance commitments were not credible. The sample of observed crises and civil wars would contain only cases where the American alliance commitment was shaky, perhaps leading to the conclusion that alliance commitments were not strongly associated with subsequent American intervention on behalf of its endangered allies. Although this is an important problem in principle, censored probit selection models designed to handle it turned up little evidence that it made an important difference in practice. The rho parameter was not significantly different from zero, and coefficient estimates were nearly identical to those presented in the next section. A more thorough presentation of these models can be found in the online appendix posted with the replication data. Benjamin O. Fordham 743
744 Power or Plenty? between 1918 and 2001.2 Brecher and Wilkenfeld (1997,4-5)explain that these events were selected based on two criteria: (1)a change in type and/or an increase in intensity of disruptive,that is,hostile verbal or physical interactions between two or more states,with a heightened probability of military hostilities;that,in turn,(2)destabilizes their relationship and challenges the structure of an international system-global,dominant,or subsystem. Although any crisis could affect American economic or security interests,not all the incidents included in the ICB data are relevant here.In order to test hypotheses about intervention realistically,the events examined must be reason- ably comparable.Decisions about intervention in an ongoing crisis differ from decisions to initiate a crisis in the first place.Bremer (1992),Bennett and Stam (2003),and others treat initiation of wars differently from intervention in ongoing wars for this reason.Although decisions to initiate crises certainly reveal something about intervention,the fact that there are only 20 such cases in the ICB data set limits the analytical usefulness of these events.Only decisions to join ongoing crises will be considered here.Second,some of the crises included in the ICB data occurred during wars.For example,24 crises were part of World War II,14 of them beginning after the United States had become a belligerent. Just as decisions about initiation differ from decisions about intervention,inter- vention in events taking place during wars in which the United States was already a belligerent also differ.These crises are also omitted in the analysis that follows. Finally,crises in which the United States was the target of actions by other states are not appropriate for testing hypotheses about intervention because American leaders were not able to make a decision about their involvement.Overall,393 of the 435 crises that began before 2002 were selected for analysis here. Like Regan's data,the ICB data record major power actions short of direct military intervention.The ICB data include information on economic aid,propa- ganda activity,covert action,and statements by major foreign policy officials.As with civil wars,it makes sense to set the threshold for intervention lower than full-fledged military action,which is likely to be a last resort after less costly policy instruments have failed.For purposes of the analysis presented here,the United States and its rivals were coded as intervening if they undertook some action beyond official statements and propaganda.In terms of the ICB data, intervention included military action,the provision of military advisors,military or economic aid,and covert action.By this standard,the United States inter- vened in 94 of the 393 crises selected for analysis. Operationalizing Economic and Security Interests Because security interests can encompass a wide range of considerations,includ- ing many that are difficult to observe,operationalizing the concept is not easy The analysis here will consider two considerations that have the virtue of being both important and easy to observe.The first is the presence of an alliance with one of the affected states.The security of allies has often been a major concern of American policy makers.For purposes of this analysis,states are considered allies if they have a defensive or offensive alliance with the United States accord- ing to the Alliance Treaty Obligations and Provisions (ATOP)data set (Leeds et al.2002).Civil wars taking place in American allies should be more likely to prompt U.S.intervention.Similarly,international crises in which an American 2 The ICB data include 10 additional crises from 2002 through 2004,but data on the major independent variables used here are not available for these years
between 1918 and 2001.2 Brecher and Wilkenfeld (1997, 4–5) explain that these events were selected based on two criteria: (1) a change in type and ⁄ or an increase in intensity of disruptive, that is, hostile verbal or physical interactions between two or more states, with a heightened probability of military hostilities; that, in turn, (2) destabilizes their relationship and challenges the structure of an international system—global, dominant, or subsystem. Although any crisis could affect American economic or security interests, not all the incidents included in the ICB data are relevant here. In order to test hypotheses about intervention realistically, the events examined must be reasonably comparable. Decisions about intervention in an ongoing crisis differ from decisions to initiate a crisis in the first place. Bremer (1992), Bennett and Stam (2003), and others treat initiation of wars differently from intervention in ongoing wars for this reason. Although decisions to initiate crises certainly reveal something about intervention, the fact that there are only 20 such cases in the ICB data set limits the analytical usefulness of these events. Only decisions to join ongoing crises will be considered here. Second, some of the crises included in the ICB data occurred during wars. For example, 24 crises were part of World War II, 14 of them beginning after the United States had become a belligerent. Just as decisions about initiation differ from decisions about intervention, intervention in events taking place during wars in which the United States was already a belligerent also differ. These crises are also omitted in the analysis that follows. Finally, crises in which the United States was the target of actions by other states are not appropriate for testing hypotheses about intervention because American leaders were not able to make a decision about their involvement. Overall, 393 of the 435 crises that began before 2002 were selected for analysis here. Like Regan’s data, the ICB data record major power actions short of direct military intervention. The ICB data include information on economic aid, propaganda activity, covert action, and statements by major foreign policy officials. As with civil wars, it makes sense to set the threshold for intervention lower than full-fledged military action, which is likely to be a last resort after less costly policy instruments have failed. For purposes of the analysis presented here, the United States and its rivals were coded as intervening if they undertook some action beyond official statements and propaganda. In terms of the ICB data, intervention included military action, the provision of military advisors, military or economic aid, and covert action. By this standard, the United States intervened in 94 of the 393 crises selected for analysis. Operationalizing Economic and Security Interests Because security interests can encompass a wide range of considerations, including many that are difficult to observe, operationalizing the concept is not easy. The analysis here will consider two considerations that have the virtue of being both important and easy to observe. The first is the presence of an alliance with one of the affected states. The security of allies has often been a major concern of American policy makers. For purposes of this analysis, states are considered allies if they have a defensive or offensive alliance with the United States according to the Alliance Treaty Obligations and Provisions (ATOP) data set (Leeds et al. 2002). Civil wars taking place in American allies should be more likely to prompt U.S. intervention. Similarly, international crises in which an American 2 The ICB data include 10 additional crises from 2002 through 2004, but data on the major independent variables used here are not available for these years. 744 Power or Plenty?
BENJAMIN O.FORDHAM 745 ally is an actor should be more likely to precipitate American action.In the ICB data,crisis actors are states that perceive a heightened threat of war.Interveners who do not experience such a threat are not coded as actors. Second,like ensuring the security of allies,countering the actions of rivals is an important security interest.Crises or civil wars in which American rivals have intervened should be more likely to draw American intervention as well.In order to ensure that rival intervention is influencing American actions rather than the other way around,only rival interventions that occur prior to any U.S.interven- tion are included.The strategic rivals identified by Thompson (2001)are used here.These include states that are"sufficiently threatening competitors to qual- ify as enemies''(Thompson 2001,557).In the ICB data set,intervention data were available only on the Soviet Union,China,Germany,and Japan.Cuba, which Thompson identifies as a U.S.rival from 1959 through the present,was therefore not included in the analysis of crisis intervention. Operationalizing economic interests required several additional judgments. Limitations on available data led to the selection of exports to represent the value of economic interests threatened by crises and civil wars.Economic interests in a civil war or international crisis stem from expectations about the loss of future income from a disrupted commercial relationship.Foreign direct investment is arguably more important in this respect than trade, because it reflects assets actually owned in the affected area rather than sim- ply a flow that could potentially be diverted to safer markets.Another prob- lem suggested by Copeland (1996)is that the current level of trade may not always reflect expectations about future trade.Given the difficulty of finding data on trade expectations and foreign direct investment for the time period considered here,exports are the best available proxy.Economists have found that exports and foreign direct investments are complementary.Lipsey and Weiss (1981,1984),examined a sample of nearly 1,300 U.S.firms in 1970, finding a positive relationship between exports and the output of local subsidiaries of those firms in each of 14 industries.Subsequent research sug- gests that a combination of exports and local production through foreign affiliates makes sense for multinational corporations (e.g.,Helpman 1985;Rob and Vettas 2003).Because exporters at one stage of the product cycle will often become foreign investors in the same markets (Vernon 1966),exports also reveal something about expectations for future investment income. The trade data used here are from the Department of Commerce statistics published in annual volumes of the Statistical Abstract of the United States from 1878 through 1949.Those from the post-1949 period are from the International Monetary Fund.In the case of some newly independent states,the International Monetary Fund coded trade as zero for a few years after independence when the Department of Commerce reported only regional aggregates.Because exports were not zero in these cases,these figures were estimated based on each coun- try's share of regional trade in later years.Because conflict tends to depress trade,figures from the year before the onset of the civil war or crisis are used here.Because additional trade should arguably have a declining marginal effect on policy makers'perceptions of the economic stakes,export values,expressed in millions of constant 2,000 dollars,were logged. Empirical Results This section first considers direct effects on the probability of intervention in crises and civil wars,then the relationship between trade and alliances.Finally,the analy- sis considers the total effect of the major independent variables on intervention
ally is an actor should be more likely to precipitate American action. In the ICB data, crisis actors are states that perceive a heightened threat of war. Interveners who do not experience such a threat are not coded as actors. Second, like ensuring the security of allies, countering the actions of rivals is an important security interest. Crises or civil wars in which American rivals have intervened should be more likely to draw American intervention as well. In order to ensure that rival intervention is influencing American actions rather than the other way around, only rival interventions that occur prior to any U.S. intervention are included. The strategic rivals identified by Thompson (2001) are used here. These include states that are ‘‘sufficiently threatening competitors to qualify as enemies’’ (Thompson 2001, 557). In the ICB data set, intervention data were available only on the Soviet Union, China, Germany, and Japan. Cuba, which Thompson identifies as a U.S. rival from 1959 through the present, was therefore not included in the analysis of crisis intervention. Operationalizing economic interests required several additional judgments. Limitations on available data led to the selection of exports to represent the value of economic interests threatened by crises and civil wars. Economic interests in a civil war or international crisis stem from expectations about the loss of future income from a disrupted commercial relationship. Foreign direct investment is arguably more important in this respect than trade, because it reflects assets actually owned in the affected area rather than simply a flow that could potentially be diverted to safer markets. Another problem suggested by Copeland (1996) is that the current level of trade may not always reflect expectations about future trade. Given the difficulty of finding data on trade expectations and foreign direct investment for the time period considered here, exports are the best available proxy. Economists have found that exports and foreign direct investments are complementary. Lipsey and Weiss (1981, 1984), examined a sample of nearly 1,300 U.S. firms in 1970, finding a positive relationship between exports and the output of local subsidiaries of those firms in each of 14 industries. Subsequent research suggests that a combination of exports and local production through foreign affiliates makes sense for multinational corporations (e.g., Helpman 1985; Rob and Vettas 2003). Because exporters at one stage of the product cycle will often become foreign investors in the same markets (Vernon 1966), exports also reveal something about expectations for future investment income. The trade data used here are from the Department of Commerce statistics published in annual volumes of the Statistical Abstract of the United States from 1878 through 1949. Those from the post-1949 period are from the International Monetary Fund. In the case of some newly independent states, the International Monetary Fund coded trade as zero for a few years after independence when the Department of Commerce reported only regional aggregates. Because exports were not zero in these cases, these figures were estimated based on each country’s share of regional trade in later years. Because conflict tends to depress trade, figures from the year before the onset of the civil war or crisis are used here. Because additional trade should arguably have a declining marginal effect on policy makers’ perceptions of the economic stakes, export values, expressed in millions of constant 2,000 dollars, were logged. Empirical Results This section first considers direct effects on the probability of intervention in crises and civil wars, then the relationship between trade and alliances. Finally, the analysis considers the total effect of the major independent variables on intervention. Benjamin O. Fordham 745
746 Power or Plenty? The Direct Effects of Political and Economic Interests on Intervention Table 1 presents the results of four models of American intervention in civil wars and international crises.There are good reasons to prefer a parsimonious specifi- cation (e.g.,Achen 2002;Clarke 2005;Ray 2003),but it is also possible that esti- mates from such a minimalist specification reflect related influences on intervention decisions that were omitted from the model.Models 1 and 3 include only the variables of primary theoretical interest here:alliance commit- ments,rival intervention,and exports.Models 2 and 4 add several additional independent variables reflecting considerations that might create omitted vari- able bias in the more parsimonious specification.For example,the United States might be less likely to intervene in conflicts involving militarily powerful states, but more likely to intervene in those involving its neighbors,or democratic gov- ernments.The United States might have acted more aggressively during the Cold War,or on behalf of its NATO allies.Military action might also be more likely in times of economic distress.All of these considerations might also be related to the primary independent variables,especially trade,creating omitted variable bias.In practice,including these additional independent variables has a small effect on inferences about the variables of primary theoretical interest.The coef ficient estimates for alliance commitments and rival intervention are somewhat larger;trade remains statistically insignificant. The most important empirical finding from this stage of the analysis is that security concerns about alliance commitments and rival intervention had large direct effects on American intervention,while exports were not statistically signif icant.The two security concerns had very similar effects on intervention in both civil wars and international crises.Holding the continuous independent variables at their mean value,the predicted probability of civil war intervention in the absence of an alliance or intervention by a rival state was.11.The addition of an alliance would increase this probability to .45.Rival intervention would increase it to.32.For international crises,the baseline probability of intervention was.14. TABLE 1.Probit Models of Civil War and International Crisis Intervention International Crisis Civil War Intervention Intervention Rival intervention 0.81(0.30)* 0.94(0.33)* 0.44(0.16)* 0.61(0.17)* Alliance partners involved 1.09(0.31)* 1.12(0.44)* 0.32(0.10)* 0.35(0.14)* Log of exports in previous year -0.04(0.06) 0.11(0.09) 0.01(0.01) 0.04(0.02) (millions of 2,000 dollars) Other states CINC scores/U.S. -1.02(2.07) -0.74(0.38) CINC score Log of capital to capital distance 0.73(0.42)* -0.01(0.21) from U.S. Log of population of states in -0.31(0.15)* 0.01(0.04) civil war or crisis 21-point Polity IV democracy score -0.01(0.02) -0.02(0.01) Cold War 0.85(0.37)* 0.28(0.18) U.S.GNP growth rate -0.08(0.05) -0.00(0.02) U.S.inflation rate -0.03(0.05) -0.02(0.02)◆ Number of crisis actors -0.18(0.31) Number of NATO members involved -0.22(0.18) Constant -0.88(0.29)* -10.46(6.14)* -1.09(0.12)* -1.16(1.82) Observations 150 149 393 390 Pseudo R2 0.11 0.21 0.06 0.09 Note.Asterisks indicate statistical significance at the p<05 level.One civil war and three interational crises had to be omitted from estimation in the second model because the states involved were not system members,creating missing data on many independent variables
The Direct Effects of Political and Economic Interests on Intervention Table 1 presents the results of four models of American intervention in civil wars and international crises. There are good reasons to prefer a parsimonious specifi- cation (e.g., Achen 2002; Clarke 2005; Ray 2003), but it is also possible that estimates from such a minimalist specification reflect related influences on intervention decisions that were omitted from the model. Models 1 and 3 include only the variables of primary theoretical interest here: alliance commitments, rival intervention, and exports. Models 2 and 4 add several additional independent variables reflecting considerations that might create omitted variable bias in the more parsimonious specification. For example, the United States might be less likely to intervene in conflicts involving militarily powerful states, but more likely to intervene in those involving its neighbors, or democratic governments. The United States might have acted more aggressively during the Cold War, or on behalf of its NATO allies. Military action might also be more likely in times of economic distress. All of these considerations might also be related to the primary independent variables, especially trade, creating omitted variable bias. In practice, including these additional independent variables has a small effect on inferences about the variables of primary theoretical interest. The coef- ficient estimates for alliance commitments and rival intervention are somewhat larger; trade remains statistically insignificant. The most important empirical finding from this stage of the analysis is that security concerns about alliance commitments and rival intervention had large direct effects on American intervention, while exports were not statistically significant. The two security concerns had very similar effects on intervention in both civil wars and international crises. Holding the continuous independent variables at their mean value, the predicted probability of civil war intervention in the absence of an alliance or intervention by a rival state was .11. The addition of an alliance would increase this probability to .45. Rival intervention would increase it to .32. For international crises, the baseline probability of intervention was .14. Table 1. Probit Models of Civil War and International Crisis Intervention Civil War Intervention International Crisis Intervention Rival intervention 0.81 (0.30)* 0.94 (0.33)* 0.44 (0.16)* 0.61 (0.17)* Alliance partners involved 1.09 (0.31)* 1.12 (0.44)* 0.32 (0.10)* 0.35 (0.14)* Log of exports in previous year (millions of 2,000 dollars) )0.04 (0.06) 0.11 (0.09) 0.01 (0.01) 0.04 (0.02) Other states CINC scores⁄ U.S. CINC score )1.02 (2.07) )0.74 (0.38) Log of capital to capital distance from U.S. 0.73 (0.42)* )0.01 (0.21) Log of population of states in civil war or crisis )0.31 (0.15)* 0.01 (0.04) 21-point Polity IV democracy score )0.01 (0.02) )0.02 (0.01) Cold War 0.85 (0.37)* 0.28 (0.18) U.S. GNP growth rate )0.08 (0.05) )0.00 (0.02) U.S. inflation rate )0.03 (0.05) )0.02 (0.02)* Number of crisis actors )0.18 (0.31) Number of NATO members involved )0.22 (0.18) Constant )0.88 (0.29)* )10.46 (6.14)* )1.09 (0.12)* )1.16 (1.82) Observations 150 149 393 390 Pseudo R2 0.11 0.21 0.06 0.09 Note. Asterisks indicate statistical significance at the p < .05 level. One civil war and three international crises had to be omitted from estimation in the second model because the states involved were not system members, creating missing data on many independent variables. 746 Power or Plenty?