KANTIAN PEACE S and(3)international organizations constrain decision makers by pro- moting peace in a variety of ways.Since the modern international sys- tem is far from a pacific federation of democratic states,we expect both realist and Kantian factors to affect interstate relations.We explicitly consider how realist and liberal influences at both the dyadic and the systemic level have altered the functioning of the international system, addressing the role of the leading state and the influence of the chang- ing Kantian variables over time. Evidence for the pacific benefits of economic interdependence and membership in intergovernmental organizations(IGOs)is less widely accepted than is that for the democratic peace,and it has been sub- jected to less extensive critical scrutiny.We alone have assessed the ef- fect of IGOs on confict at the dyadic level of analysis.Moreover, theoretical expectations regarding the impact of trade and IGOs are more diverse than those concerning democracy.No one hypothesizes that democracies are more likely to fight each other than are other poli- ties;but the liberal view of the pacific effects of trade is contradicted by those who expect confict over the division of the gains from trade and by the dependency school and its intellectual predecessors and descen- dants,who expect conflict between large and small states.As for IGOs, a plausible view might be that states form or join international organi- zations to manage-albeit often without success-disputes with their adversaries,the UN being an example.More commonly,realists regard international institutions as nearly irrelevant to the security issues at the heart of high politics,with no effect independent of existing power re- lations.10 Even among those who hold that trade or IGOs play a positive role in promoting peace,the reasons advanced vary.Rational choice theorists emphasize political actors'complementary economic interests in maintaining peaceful interstate relations-interests that are reflected in the decisions of national leaders.Fearful of the domestic political consequences of losing the benefits of trade,policymakers avoid the use of force against states with which they engage in economically impor- tant trade.But one can also devise constructivist explanations about how the communication associated with trade builds cross-national sentiments of shared identity.11 A useful review is Susan McMillan,"Interdependence and Conflict,"Mershon International Stud- ies Review 41,no.1(1997). 10 John Mearsheimer,"The False Promise of International Institutions,"International Security 19 (Vinter199495). 1 Emanuel Adler and Michael Barnett,"Security Communities in Theoretical Perspective,"in Adler and Barnett(fn.6);Alexander Wendt,Social Theory of International Politics (New York:Cam- bridge University Press,1999).For microlevel evidence that trading contacts expand elites'views ofKANTIAN PEACE 5 and (3) international organizations constrain decision makers by pro moting peace in a variety of ways. Since the modern international sys tem is far from a pacific federation of democratic states, we expect both realist and Kantian factors to affect interstate relations. We explicitly consider how realist and liberal influences at both the dyadic and the systemic level have altered the functioning of the international system, addressing the role of the leading state and the influence of the chang ing Kantian variables over time. Evidence for the pacific benefits of economic interdependence and membership in intergovernmental organizations (iGOs) is less widely accepted than is that for the democratic peace, and it has been sub jected to less extensive critical scrutiny. We alone have assessed the ef fect of IGOs on conflict at the dyadic level of analysis. Moreover, theoretical expectations regarding the impact of trade and IGOs are more diverse than those concerning democracy. No one hypothesizes that democracies are more likely to fight each other than are other poli ties; but the liberal view of the pacific effects of trade is contradicted by those who expect conflict over the division of the gains from trade and by the dependency school and its intellectual predecessors and descen dants, who expect conflict between large and small states.9 As for IGOs, a plausible view might be that states form or join international organi zations to manage?albeit often without success?disputes with their adversaries, the UN being an example. More commonly, realists regard international institutions as nearly irrelevant to the security issues at the heart of high politics, with no effect independent of existing power re lations.10 Even among those who hold that trade or IGOs play a positive role in promoting peace, the reasons advanced vary. Rational choice theorists emphasize political actors' complementary economic interests in maintaining peaceful interstate relations?interests that are reflected in the decisions of national leaders. Fearful of the domestic political consequences of losing the benefits of trade, policymakers avoid the use of force against states with which they engage in economically impor tant trade. But one can also devise constructivist explanations about how the communication associated with trade builds cross-national sentiments of shared identity.11 9 A useful review is Susan McMillan, "Interdependence and Conflict," Mershon International Stud ies Review 41, no. 1 (1997). 10 John Mearsheimer, "The False Promise of International Institutions," International Security 19 (Winter 1994-95). 11 Emanuel Adler and Michael Barnett, "Security Communities in Theoretical Perspective," in Adler and Barnett (fn. 6); Alexander Wendt, Social Theory of International Politics (New York Cam bridge University Press, 1999). For microlevel evidence that trading contacts expand elites' views of