John R. Oneal and Bruce Russett, “The Classical Liberals Were Right: Democracy, Interdependence, and Conflict, 1950–1985,” International Studies Quarterly 40, no. 2 (1997); Russett, Oneal, and David R. Davis, “The Third Leg of the Kantian Tripod: International Organizations and Militarized Disputes, 1950–85,” International Organization 52, no. 3 (1998); Oneal and Russett, “Assessing the Liberal Peace with Alternative Specifications: Trade Still Reduces Conflict Journal of Peace Research 36, no. 4 (1999). Here we extend this line of research in three ways: (1) providing a conceptual synthesis of Kantian and realist theories that treats conflict as inherent but subject to important constraints; (2) extending the temporal domain for trade and IGOs into the nineteenth century; and (3) assessing realist theories regarding the role of the hegemon and Kantian theories about systemic influences in a way that addresses, among others, constructivist and evolutionary perspectives on the international system. Note that the Kantian influences may be mutually reinforcing in a dynamic system of feedback loops, as suggested by Wade Huntley, “Kant’s Third Image: Systemic Sources of the Liberal Peace,” International Studies Quarterly 40, no. 4 (1996); and Russett, “A Neo-Kantian Perspective: Democracy, Interdependence, and International Organizations in Building Security Communities,” in Emanuel Adler and Michael Barnett, eds., Security Communities in Comparative Perspective (New York: Cambridge University Press, 1998).
We and others have begun to address some of these links, such as greater trade between democracies, the possibility that trade is diminished between conflicting states, the effect of democracy, trade, and peace in increasing membership in international organizations, and the effect of conflict on democracy. On the first, see Harry Bliss and Russett, “Democratic Trading Partners: The Liberal Connection,” Journal of Politics 58, no. 4 (1998), and James Morrow, Randolph Siverson, and Tessa Tabares, “The Political Determinants of International Trade: The Major Powers, 1907–90,” American Political Science Review 92, no. 3 (1998); on the second, see Soo Yeon Kim, “Ties That Bind: The Role of Trade in International Conflict Processes” (Ph.D. diss., Yale University, 1998); on the third, see Russett, Oneal, and Davis (this fn.); and on the last, see Oneal and Russett, “Why An Identified Systemic Model of the Democratic Peace Nexus’ Does Not Persuade,” Defence and Peace Economics 11, no. 2 (2000).