The Nexus of Market Society, Liberal Preferences, and Democratic Peace: Interdisciplinary Theory and Evidence MICHAEL MOUSSEAU Koc ¸ University Drawing on literature from Anthropology, Economics, Political Science and Sociology, an interdisciplinary theory is presented that links the rise of contractual forms of exchange within a society with the proliferation of liberal values, democratic legitimacy, and peace among democratic nations. The theory accommodates old facts and yields a large number of new and testable ones, including the fact that the peace among democracies is limited to market-oriented states, and that market democraciesFbut not the other democraciesFperceive common inter- ests. Previous research confirms the first hypothesis; examination herein of UN roll call votes confirms the latter: the market democracies agree on global issues. The theory and evidence demonstrate that (a) the peace among democratic states may be a function of common interests derived from common economic structure; (b) all of the empirical research into the democratic peace is underspecified, as no study has considered an interaction of democracy with economic structure; (c) interests can be treated endogenously in social research; and (d) several of the premier puzzles in global politics are causally relatedFincluding the peace among democracies and the association of democratic stability and liberal political culture with market-oriented economic development. Europe is uniting around the values we share –– peace and stability, democracy and human rights. –– U.S. president Clinton, remarks at the NATO 50th Anniversary Summit, April 22, 1999 1 Among policymakers and the media we frequently encounter references to the ‘‘like-minded, market-oriented democracies’’ (Cohen, 1998). ‘‘A community of market democracies,’’ goes the fashionable platitude, ‘‘upholds common standards of human rights y where nations cooperate to make war unthinkable.’’ 2 The Author’s note: An earlier version of this paper was presented at the 1998 Annual Meeting of the Peace Science Society (International), New Brunswick, NJ. For helpful comments I thank Erik Gartzke, Douglas Lemke, Patrick James, and the anonymous reviewers. Of course, all errors are my own. For research assistance I thank Melis So ¨g ˇu ¨ttekin. 1 The White House, 1999. Remarks by the president on foreign policy, 5 June. www.pub.whitehouse.gov/urires/ I2R?urn:pdi://oma.eop.gov.us/1999/4/, 22/13.text. 2 Quotes are of U.S. president William Clinton. See Ibid. and ‘‘Address by the President to the 48th session of the United Nations General Assembly, 27 September 1993’’(www.pub.whitehouse.gov/urires/I2R?urn:pdi://oma.eop.- gov.us/1993/9/, 27/4.text). r 2003 International Studies Association. Published by Blackwell Publishing, 350 Main Street, Malden, MA 02148, USA, and 9600 Garsington Road, Oxford OX4 2DQ, UK. International Studies Quarterly (2003) 47, 483–510