Erik Gartzke

Investing in the Peace: Economic Interdependence and International Conflict

Research appears to substantiate the liberal conviction that trade fosters global peace. Still, existing understanding of linkages between cone ict and international economics is limited in at least two ways. First, cross-border economic relationships are far broader than just trade. Global capital markets dwarf the exchange of goods and services, and states engage in varying degrees of monetary policy coordination. Second, the manner in which economics is said to inhibit cone ict behavior is implausible in light of new analytical insights about the causes of war. We discuss, and then demonstrate formally, how interdependence can ine uence states’ recourse to military violence. The risk of disrupting economic linkages— particularly access to capital— may occasionally deter minor contests between interdependent states, but such opportunity costs will typically fail to preclude militarized disputes. Instead, interdependence offers nonmilitarized avenues for communicating resolve through costly signaling. Our quantitative results show that capital interdependence contributes to peace independent of the effects of trade, democracy, interest, and other variables. Students of world politics have long argued that peace is a positive externality of global commerce. Theorists like Montesquieu and Kant and practitioners like Woodrow Wilson asserted that economic relations between states pacify political interaction. Mounting evidence in recent years appears to substantiate these claims. Multiple studies, many identie ed with the democratic peace, link interstate trade with reductions in militarized disputes or wars. 1 While we concur with the evolving

War Is in the Error Term

At least since Thucydides, students of international relations have sought rational explanations for the advent of war. Rationalist explanations assume purposive action; states are said to make reasoned decisions about the use of force. Although rationalist explanations have proven persuasive, durable, and offer the basis for cumulative theorizing, they also imply substantial limits on what we can know about war. I show that the most general rationalist explanation for war also dictates that the onset of war is theoretically indeterminate. We cannot predict in individual cases whether states will go to war, because war is typically the consequence of variables that are unobservable ex ante, both to us as researchers and to the participants. Thinking probabilistically continues to offer the opportunity to assess international conflict empirically. However, the realization that uncertainty is necessary theoretically to motivate war is much different from recognizing that the empirical world contains a stochastic element. Accepting uncertainty as a necessary condition of war implies that all other variables—however detailed the explanation—serve to eliminate gradations of irrelevant alternatives. We can progressively refine our ability to distinguish states that may use force from those that are likely to remain at peace, but anticipating wars from a pool of states that appear willing to fight will remain problematic. For example, we may achieve considerable success in anticipating crises, but our ability to predict which crises will become wars will probably prove little better than the naive predictions of random chance. The need for uncertainty to account for war means that the same conditions thought to account for war must also exist among states not destined to fight. Otherwise, states themselves will differentiate between opponents in a way that either removes the motives for war or restores uncertainty. It has long been accepted that social processes possess an element of uncertainty, but the centrality of uncertainty to rationalist explanations for war means that the advent of war is itself stochastic. War is literally in the “error term.â€

Preferences and the Democratic Peace

A debate exists over whether ~and to what degree! the democratic peace is explained by joint democracy or by a lack of motives for conflict between states that happen to be democratic. Gartzke ~1998! applies expected utility theory to the democratic peace and shows that an index of states’ preference similarity based on United Nations General Assembly roll-call votes ~affinity! accounts for much of the lack of militarized interstate disputes ~MIDs! between democracies. Oneal and Russett ~1997b, 1998, 1999! respond by arguing that UN voting is itself a function of regime type—that democracy “causes” affinity. Oneal and Russett seek to demonstrate their thesis by regressing affinity on democracy and other variables from a standard model of the democratic peace. I replicate results reported by Oneal and Russett and then extend the analysis in several ways. I find that the residuals from Oneal and Russett’s regression of affinity remain highly significant as a predictor of the absence of MIDs. Further, significance for democracy is shown to be fragile and subject to variable construction, model specification, and the choice of estimation procedure. A fundamental positive goal of international relations is the explication of costly contests—students of world politics seek to understand why states fight. A fundamental normative goal of international relations is of course the alleviation of such contests. The democratic peace—the observation that liberal dyads seldom engage in militarized disputes—is exciting precisely because it offers important opportunities for addressing both of these goals. Still, unification of the two goals remains contingent on the character of the explanation. Any account that fits the facts is potentially useful in positive terms, but to fulfill the normative objective, accounts must offer causal variables either that are socially manipulable or that trend in a desirable direction. If the causes of the democratic peace lie in liberal politics or economics, then the foreign policies of leading powers or the inexorable march of time may yield an expanding sphere of pacific relations. If instead the democratic peace is substantially explained by variables that are unresponsive to autonomous policy efforts or that are more likely to wander than to trend, then the prospects for long-term peace remain in greater doubt.

Determinants of Nuclear Weapons Proliferation

Nuclear weapons proliferation is a topic of intense interest and concern among both academics and policy makers. Diverse opinions exist about the determinants of proliferation and the policy options to alter proliferation incentives. We evaluate a variety of explanations in two stages of nuclear proliferation, the presence of nuclear weapons production programs and the actual possession of nuclear weapons. We examine proliferation quantitatively, using data collected by the authors on national latent nuclear weapons production capability and several other variables, while controlling for the conditionality of nuclear weapons possession based on the presence of a nuclear weapons program. We find that security concerns and technological capabilities are important determinants of whether states form nuclear weapons programs, while security concerns, economic capabilities, and domestic politics help to explain the possession of nuclear weapons. Signatories to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) are less likely to initiate nuclear weapons programs, but the NPT has not deterred proliferation at the system level.

Political System Similarity And The Choice of Allies

Does the nature of a nations political institutions influence the types of countries with which it allies? Some previous research has suggested that democracies tend to ally with other democracies. This study reexamines alliance patterns by assessing the broader linkage between regime type and alliance partnership. The authors present a refinement of previous research designs, using new data from Polity III and the updated correlates of war (COW) alliance data sets to analyze all alliances from 1815 to 1992. The bipolar alliance structures of the cold war (NATO and the Warsaw Pact) appear to be aberrations in their strong ideological content. In general, there is very little correlation between alliance dyads and regime type. Surprisingly, democracies are less likely to ally with one another than highly autocratic regimes. Regimes of most types seem to prefer to ally with partners of dissimilar type. The authors conclude that this is due to so-called gains from trade within alliance dyads.

Measure for Measure: Concept Operationalization and the Trade Interdependence-Conflict Debate

While most quantitative studies find a negative relationship between economic interdependence and interstate disputes, research by Barbieri finds that interdependence precipitates conflict. Participants in the debate suggest several causes, but we show that alternative variable constructions are sufficient to account for the discrepant findings. A simple formal equivalence unites respective operationalizations of dyadic interdependence used by Oneal & Russett (trade dependence, trade ij /GDP i ) and Barbieri (trade share, trade i /trade i ) with the consensus construction of monadic trade openness (trade i /GDP i ). We also show that Barbieris trade share is negatively correlated with openness. Arguments in the article are verified through large-sample quantitative regression analyses of the two competing dyadic variable constructions and trade openness on MID onset. The results of these dyadic regression analyses show that trade share increases the probability of MID onset, trade dependence decreases the probability of MID onset and, correspondingly, that trade openness is negatively correlated with MID onset.

Identity and conflict: Ties that bind and differences that divide

Conventional wisdom suggests that cultural differences make conflict more likely. Culture can unite and divide, but there exists little agreement among scholars over how identity forms among states, what distinctions are most salient, and when conflict is more likely. Researchers have tended to ‘confirm’ the role of identity in an ex post facto fashion, looking only at actual conflicts with cultural differences, without considering the opportunities for conflict among groups. We address a series of problems with existing conceptions of identity and ethnicity. We distinguish between shared and different culture by religion, language, and ethnicity. Rather than equating states with just the dominant groups, we also consider how relations involving secondary groups present in other states can give rise to conflict. We examine empirically the relationship between cultural similarities and differences and international dispute behavior in the post-World War II era. Our results suggest that culture and identity influence dispute patterns, but in ways that run counter to conventional beliefs. We find little evidence that conflict is more common between states where the dominant groups come from different cultural affiliations. If anything, our results suggest that violence is more likely among states with similar cultural ties, even when controlling for other determinants of conflict. Moreover, dyads where a group is politically privileged in one state but a minority in another tend to be particularly conflict prone. We conclude with suggestions for reorienting the study of identity and conflict in more constructive ways than the clash of civilization thesis.

The Myth of Cyberwar: Bringing War in Cyberspace Back Down to Earth

Cyberwar has been described as a revolution in military affairs, a transformation of technology and doctrine capable of overturning the prevailing world order. This characterization of the threat from cyberwar, however, reflects a common tendency to conflate means and ends; studying what could happen in cyberspace (or anywhere else) makes little sense without considering how conflict over the internet is going to realize objectives commonly addressed by terrestrial warfare. To supplant established modes of conflict, cyberwar must be capable of furthering the political ends to which force or threats of force are commonly applied, something that in major respects cyberwar fails to do. As such, conflict over the internet is much more likely to serve as an adjunct to, rather than a substitute for, existing modes of terrestrial force. Indeed, rather than threatening existing political hierarchies, cyberwar is much more likely to simply augment the advantages of status quo powers.

Bargaining, Nuclear Proliferation, and Interstate Disputes

Contrasting claims about the consequences of nuclear weapons rely on different interpretations about how leaders respond to risk, uncertainty, and the balance of power. Nuclear optimists use deterrence theory to argue that proliferation can promote stability and inhibit the use of force. Pessimists argue that proliferation precipitates nuclear hubris, accident, or anger that heightens the risk of war. It is also possible that nuclear weapons have no net effect on dispute propensity. Since states fashion their own bargains, nuclear status is bound to influence the distribution of influence. Proliferation also reflects existing tensions, biasing upward the apparent impact of nuclear weapons on conventional conflict. Instrumenting for the decision to proliferate, the authors find that nuclear weapons increase diplomatic status without much affecting whether states fight.

A Strategic Approach to Nuclear Proliferation

Authors’ Note: We are grateful for generous financial support from the Department of Political Science at the University of California at San Diego, the Government Department at Georgetown University, the University of California’s Institute on Global Conflict and Cooperation, and the Project on Managing the Atom and the International Security Program both at the Belfer Center for Science and International Affairs at Harvard University. Journal of Conflict Resolution Volume 53 Number 2 April 2009 151-160