¹ For the major initial statements of the thesis, see Babst, Dean, “A Force for Peace” Industrial Research 14 (April 1972)Google Scholar; Small, Melvin and Singer, David, “The War-Proneness of Democratic Regimes, 1816–1965,” Jerusalem Journal of International Relations 1, no. 4 (1976)Google Scholar; Rummel, R., “Libertarianism and International Violence” Journal of Conflict Resolution 27 (March 1983)CrossRefGoogle Scholar; Doyle, Michael, “Kant, Liberal Legacies, and Foreign Affairs,” Philosophy and Public Affairs 12 (Summer and Autumn 1983)Google Scholar; Chan, Steve, “Mirror, Mirror on the Wall: Are the Free Countries More Pacific?” Journal of Conflict Resolution 28 (December 1984)CrossRefGoogle Scholar; Domke, William, War and the Changing Global System (New Haven: Yale University Press, 1988)Google Scholar; Maoz, Zeev and Abdolali, Nasrin, “Regime Type and International Conflict, 1816–1976” Journal of Conflict Resolution 33 (March 1989)CrossRefGoogle Scholar; Maoz, Zeev and Russett, Bruce, “Normative and Structural Causes of Democratic Peace, 1946–1986” American Political Science Review 87 (September 1993)CrossRefGoogle Scholar; Russett, Bruce, Grasping the Democratic Peace (Princeton: Princeton University Press, 1993)Google Scholar.

² For the critics, see Layne, Christopher, “Kant or Cant: The Myth of the Democratic Peace,” International Security 19, no. 2 (1994)CrossRefGoogle Scholar; idem, “Lord Palmerston and the Triumph of Realism: Anglo-French Relations, 1830–48,” in Elman, M., ed., Path to Peace: Is Democracy the Answer? (Cambridge: MIT, 1997)Google Scholar; Spiro, David, “The Insignificance of the Liberal Peace,” International Security 19, no. 2 (1994)CrossRefGoogle Scholar; Cohen, Raymond, “Pacific Unions: A Reappraisal of the Theory that ‘Democracies Do Not Go to War with Each Other,’” Review of International Studies 20 (July 1994)CrossRefGoogle Scholar; Oren, Ido, “From Democracy to Demon: Changing American Perceptions of Germany during World War I,” International Security 20, no. 2 (1995)Google Scholar; Farber, Henry and Gowa, Joanne, “Politics and Peace,” International Security 20, no. 2 (1995)CrossRefGoogle Scholar. For the DP theorists' response, see Russet (fn. 1), 16–19; Owen, John, “How Liberalism Produces Democratic Peace,” International Security 19, no. 2 (1994)CrossRefGoogle Scholar, idem, Liberal Peace, Liberal War (Ithaca, N.Y.: Cornell University Press, 1997)Google Scholar; Ray, James, Democracy and International Conflict: An Evaluation of the Democratic Peace Proposition (Columbia: University of South Carolina, 1995)Google Scholar; Maoz, Zeev, “The Controversy over the Democratic Peace: Rearguard Action or Cracks in the Wall?” International Security 22, no. 1 (1997)CrossRefGoogle Scholar; Russett, Bruce and Oneal, John, Triangulating Peace: Democracy, Interdependence and International Organizations (New York: W. W. Norton, 2001), 111–14Google Scholar. For the expansion of the initial thesis to MID in general, see Raymond, Gregory, “Democracies, Disputes, and Third-Party Intermediaries” Journal of Conflict Resolution 38 (March 1994)CrossRefGoogle Scholar; Dixon, William, “Democracy and the Peaceful Settlement of International Conflict” American Political Science Review 88 (March 1994)CrossRefGoogle Scholar; Rousseau, David, Gelpi, Christopher, Reiter, Dan, and Huth, Paul, “Assessing the Dyadic Nature of the Democratic Peace, 1918–1988” American Political Science Review 90 (September 1996)CrossRefGoogle Scholar; Rioux, Jean-Sebastien, “A Crisis-Based Evaluation of the Democratic Peace Proposition” Canadian Journal of Political Science 31 (June 1998)CrossRefGoogle Scholar; Mousseau, Michael, “Democracy and Compromise in Militarized Interstate Conflicts, 1816–1992,” Journal of Conflict Resolution 42 (April 1998)CrossRefGoogle Scholar.

³ Mansfield, Edward and Snyder, Jack, “Democratization and the Danger of War” International Security 20, no. 1 (1995)CrossRefGoogle Scholar; Snyder, Jack, From Voting to Violence: Democratization and Nationalist Conflict (New York: W. W. Norton, 2000)Google Scholar; Mansfield, Edward and Snyder, Jack, “Incomplete Democratization and the Outbreak of Military Disputes,” International Studies Quarterly 46 (December 2002)CrossRefGoogle Scholar; Gaubatz, Kurt, Elections and War: The Electoral Incentives in the Democratic Politics of War andPeace (Stanford, Calif.: Stanford University Press, 1999)Google Scholar, chap. 2; Huth, Paul and Allee, Todd, The Democratic Peace and Territorial Conflict in the Twentieth Century (New York: Cambridge University Press, 2002)Google Scholar. Others have contended that it was regime change in general rather than the democratic transition that accounts for greater belligerency, or they dispute the evidence on various grounds: Maoz, Zeev, “Joining the Club of Nations: Political Development and International Conflict, 1816–1976” International Studies Quarterly 33 (June 1989)CrossRefGoogle Scholar; Walt, Stephen, Revolution and War (Ithaca, N.Y.: Cornell University Press, 1996)Google Scholar; Enterline, Andrew, “Driving while Democratizing” International Security 20, no. 4 (1996)Google Scholar; idem, “Regime Changes and Interstate Conflict, 1816–1992,” Political Research Quarterly 51 (June 1998)Google Scholar; Enterline, Andrew and Greig, Michael, “Beacons of Hope? The Impact of Imposed Democracy on Regional Peace, Democracy, and Prosperity” Journal of Politics 67 (November 2005)CrossRefGoogle Scholar; Gleditsch, Kristian and Ward, Michael, “War and Peace in Space and Time: The Role of Democratization” International Studies Quarterly 44 (March 2000)CrossRefGoogle Scholar; Ward, Michael and Gleditsch, Kristian, “Democratizing for Peace” American Political Science Review 92 (March 1998)CrossRefGoogle Scholar; Russett and Oneal (fn. 2), 51–52, 116–22; Oneal, John, Russett, Bruce, and Berbaum, Michael, “Causes of Peace: Democracy, Interdependence, and International Organizations, 1885–1992” International Studies Quarterly 47 (September 2003), 383–84CrossRefGoogle Scholar; Mitchell, Sara and Prins, Brandon, “Beyond Territorial Contiguity: Issues at Stake in Democratic Militarized Interstate Disputes,” International Studies Quarterly 43 (March 1999)CrossRefGoogle Scholar; Rousseau, David, Democracy and War (Stanford, Calif.: Stanford University Press, 2005)Google Scholar, chap. 6.

⁴ Maoz and Abdolali (fn. 1); Chan, Steve, “In Search of Democratic Peace: Problems and Promise” Mershon International Studies Review 41 (May 1997), 83CrossRefGoogle Scholar.

⁵ The correlation between the level of liberalism and peace was first suggested by Rummel (fn. 1) and incorporated in his Power Kills: Democracy as a Method of Nonviolence (New Brunswick, N.J.: Transaction, 1997)Google Scholar, 5 and chap. 3; echoed by Ray (fn. 2), 16. Historical gradualism is tentatively noted in the 1992 article by Bruce Russet and Zeev Maoz, incorporated in Russet (fn. 1), 72–73; more fully developed in Maoz (fn. 2); and is integral in Russett and Oneal (fn. 2), 111–14. Some critics have attributed the absence of war among the democracies to the coalition effect of the alliances that they formed against joint enemies—the Axis powers and the Soviet bloc: Siverson, Randolph and Emmons, Julian, “Birds of a Feather: Democratic Political Systems and Alliances Choices” Journal of Conflict Resolution 35 (June 1991)CrossRefGoogle Scholar; Farber and Gowa (fn. 2); Gowa, Joanne, Ballots and Bullets: The Elusive Democratic Peace (Princeton: Princeton University Press, 1999)Google Scholar; Simon, Michael and Gartzke, Erik, “Political System Similarity and the Choice of Allies” Journal of Conflict Resolution 40 (December 1996)Google Scholar; Lai, Brian and Reiter, Dan, “Democracy, Political Similarity, and International Alliances, 1812–1992” Journal of Conflict Resolution 44 (April 2000)Google Scholar; Henderson, Errol, Democracy and War: The End an Illusion (Boulder, Colo.: Lynne Rienner, 2002)Google Scholar, chap. 2.

⁶ Russet and Maoz, in Russet (fn. 1), 86. Generally regarding today's Third World: Friedman, Edward, “The Painful Gradualness of Democratization: Proceduralism as a Necessary Discontinuous Revolution,” in Handelman, H. and Tessler, M., eds., Democracy and Its Limits: Lessons from Asia, Latin America, and the Middle East (Notre Dame, Ind.: University of Notre Dame, 1999)Google Scholar.

⁷ On the pros and cons, see Waltz, Kenneth, Theory of International Politics (Reading, Mass.: Addison, 1979), 212–15Google Scholar; Doyle (fn. 1), 231–32; Mansfield, Edward, Power, Trade, and War (Princeton: Princeton University Press, 1994)Google Scholar; Barbieri, Katherine, “Economic Interdependence: A Path to Peace or a Source of Interstate Conflict?” Journal of Peace Research 33 (February 1996)CrossRefGoogle Scholar; Copeland, Dale, “Economic Interdependence and War: A Theory of Trade Expectations” International Security 20, no. 4 (1996)CrossRefGoogle Scholar; Mansfield, Edward and Pollins, Brian, eds., Economic Interdependence and International Conflict (Ann Arbor: University of Michigan, 2003)CrossRefGoogle Scholar; Polachek, Solomon, “Why Democracies Cooperate More and Fight Less: The Relationship between Trade and International Cooperation,” Review of International Economics 5 (August 1997)CrossRefGoogle Scholar; Barbieri, Katherine and Schneider, Gerald, “Globalization and Peace: Assessing New Directions in the Study of Trade and Conflict” Journal of Peace Research 36 (July 1999)CrossRefGoogle Scholar.

⁸ This was originally demonstrated by Domke (fn. 1); and impressively elaborated by Russett and Oneal (fn. 2).

⁹ The most comprehensive and up-to-date estimates are found in Maddison, Angus, The World Economy: A Millennial Perspective (Paris: OECD, 2001), 28CrossRefGoogle Scholar, 90, 126, 183–86, 264–65; it more or less renders all earlier work obsolete.

¹⁰ The best studies are Mousseau, Michael, “Market Prosperity, Democratic Consolidation, and Democratic Peace” Journal of Conflict Resolution 44 (August 2000)CrossRefGoogle Scholar; idem, “The Nexus of Market Society, Liberal Preferences, and Democratic Peace” International Studies Quarterly 47 (December 2003)Google Scholar; idem, “Comparing New Theory with Prior Beliefs: Market Civilization and the Democratic Peace,” Conflict Management and Peace Science 22, no. 1 (2005)Google Scholar; Mousseau, Michael, Hegre, Havard, and Oneal, John, “How the Wealth of Nations Conditions the Liberal Peace” European Journal of International Relations 9 (June 2003)CrossRefGoogle Scholar. With respect to the first (and last) of these articles, however, Bruce Russett has suggested to me that a close look shows that joint democracy loses statistical significance only at a GDPpc level of the lowest 10 percent of democratic dyads. Nevertheless, the coefficient for effect on conflict remains negative until one hits a GDP level that contains only a single democracy. This would seem to make the statistical finding very thin. See also Polachek, “Why Democracies Cooperate More and Fight Less”; Hegre, Håvard, “Development and the Liberal Peace: What Does It Take to Be a Trading State?” Journal of Peace Research 37 (January 2000)CrossRefGoogle Scholar. The correlation had already been suggested by Benoit, Kenneth, “Democracies Really are More Pacific (in General),” Journal of Conflict Resolution 40 (December 1996)CrossRefGoogle Scholar; the article is limited to the years 1960–80.

¹¹ Henderson, Errol and Singer, David, “Civil War in the Post-Colonial World, 1946–92” Journal of Peace Research 37 (May 2000)CrossRefGoogle Scholar; Henderson (fn. 5), chap. 5.

¹² The seminal modern work is Lipset, Seymour, Political Man (New York: Anchor, 1963)Google Scholar, esp. chaps. 1–2; see also Dahl, Robert, Polyarchy (New Haven: Yale University Press, 1971)Google Scholar, chap. 5; Huntington, Samuel, The Third Wave: Democratization in the Late Twentieth Century (Norman: University of Oklahoma, 1991), 59–72Google Scholar; Diamond, Larry, “Economic Development and Democracy Reconsidered,” in Marks, G. and Diamond, L., eds., Reexamining Democracy (Newbury Park, Calif.: Sage, 1992)Google Scholar.

¹³ Mousseau (fn. 10, 2000); Marks and Diamond (fn. 12), passim.

¹⁴ Zakaria, Fareed, “The Rise of Illiberal Democracy,” Foreign Affairs 76, no. 6 (1997)CrossRefGoogle Scholar; Diamond, Larry, Developing Democracy (Baltimore: Johns Hopkins University Press, 1999)Google Scholar, esp. 34–60, 279–80; Karatnycky, Adrian, “The Decline of Illiberal Democracy” Journal of Democracy 10 (January 1999)CrossRefGoogle Scholar.

¹⁵ See fnn. 3 and 4 above.

¹⁶ Bruce Russett and William Antholis, “The Imperfect Democratic Peace of Ancient Greece,” reprinted in Russett (fn. 1), chap. 3.

¹⁷ Weart, Spencer, Never at War: Why Democracies Will Not Fight One Another (New Haven: Yale University Press, 1998)Google Scholar. This was criticized by Eric Robinson, a leading expert on early Greek democracies; , Robinson, “Reading and Misreading the Ancient Evidence for Democratic Peace” Journal of Peace Research 38 (September 2001)Google Scholar, resulting in a short exchange in the same issue: Weart, 609–13; Robinson, 615–17. See also the criticism by the leading authority on the Greek polis and fourth-century BC Athenian democracy: Hansen, Mogens and Nielsen, Thomas, An Inventory of Archaic and Classical Poleis (Oxford: Oxford University Press, 2004), 84–85Google Scholar.

¹⁸ Weart (fn. 17) postpones any mention of the first Athenian Empire to as late in his book as possible and then summarily disposes of this inconvenience (p. 246). The problem was better acknowledged by Russett and Antholis (fn. 17); Bachteler, Tobias, “Explaining the Democratic Peace: The Evidence from Ancient Greece Reviewed” Journal of Peace Research 34 (August 1997)CrossRefGoogle Scholar.

¹⁹ The ancient sources for fourth-century BC Greece are varied and patchy. N. Hammond can serve as a useful synthesis; , Hammond, A History of Greece to 322 BC (Oxford: Oxford University Press, 1986)Google Scholar. David Hume offers a thoroughly misleading account of the above war and the Battle of Mantinea (which he does not even name!) that clearly refutes his thesis; , Hume, “Of the Balance of Power,” in , Hume, Essays: Literary, Moral and Political (London: Routledge, 1894), 198Google Scholar; Weart (fn. 17), 25–26.

²⁰ Yakobson, Alexander, Elections and Electioneering in Rome (Stuttgart: Steiner, 1999)Google Scholar.

²¹ Weart (fn. 17) does not at all discuss Rome, and not because of absentmindedness. For he mentions Rome once, in his appendix of problematic cases (p. 297), where he lamely excuses himself from discussing it on the grounds that we lack information about Carthage.

²² Doyle (fn. 1), 212.

²³ Cf. Rosecrance, Richard, The Rise of the Trading State: Commerce and Conquest in the Modern World (New York: Basic Books, 1986)Google Scholar; idem, The Rise of the Virtual State (New York: Basic Books, 1999)Google Scholar.

²⁴ Russett and Oneal (fn. 2), chap. 1.

²⁵ Melvin Small and David Singer give no basis for comparison to earlier times, while also encompassing the widest range of development—in effect different worlds: preindustrial and industrial; Small and Singer, Resort to Arms: International and Civil Wars, 1816–1980 (Beverly Hills: Sage, 1982)Google Scholar. But see Levy, Jack, War in the Modern Great Power System, 1495–1975 (Lexington: University Press of Kentucky, 1983)Google Scholar, esp. 112–49. Levy concentrates on the great powers' wars among themselves, that is, the major wars by the most advanced states. See also Luard, Evan, War in International Society (London: Tauris, 1986), 53Google Scholar, 67.

²⁶ Small and Singer (fn. 25), 156–57, 198–201; Levy (fn. 25), 136–37, 150–68; Luard (fn. 25), 67–81.

²⁷ John Mueller overlooks the decline of war in the century before 1914 and fails to account for the deeper sources of the “obsolescence”; , Mueller, Retreat from Doomsday: The Obsolescence of Major War (New York: Basic Books, 1989)Google Scholar. Lars-Erik Cederman detects a decline in belligerency among nonde-mocracies after 1945, but the main decline occurred in comparison with the pre-1815 period, which he does not examine. His “learning mechanism” also has no apparent motivating factor; , Cederman, “Back to Kant: Reinterpreting the Democratic Peace as a Macro historical Learning Process” American Political Science Review 95 (March 2001)Google Scholar.

²⁸ Moltke, Helmuth von, Essays, Speeches and Memoirs (New York: Harper, 1893)Google Scholar, 1:276–77.

²⁹ Maoz and Russett (fn. 1); Russet and Oneal (fn. 2), 151–53.

³⁰ See the studies in fn. 10 above.

³¹ Liberman, Peter, Does Conquest Pay? The Exploitation of Occupied Industrial Societies (Princeton: Princeton University Press, 1996)Google Scholar.

³² Merom, Gil, How Democracies Lose Small Wars (New York: Cambridge University Press, 2003)CrossRefGoogle Scholar.

³³ This is mostly demonstrated in the democracies' record of much less intense wars during the twentieth century (far lower casualties, partly because of far weaker rivals) and far fewer civil wars: Rummel (fn. 1); idem (fn. 5); Domke (fn. 1); Bremer, Stuart, “Dangerous Dyads: Conditions Affecting the Likelihood of Interstate War, 1816–1965” Journal of Conflict Resolution 36 (June 1992)CrossRefGoogle Scholar; Benoit (fn. 10); Rousseau et al. (fn. 2); Rousseau (fn. 3); Rioux (fn. 2); Russett and Oneal (fn. 2), 49–50. Mathew Krain and Marrissa Myers find no change over time but fail to distinguish between advanced and less advanced democracies; , Krain and , Myers, “Democracy and Civil War: A Note on the Democratic Peace Proposition,” International Interactions 23, no. 1 (1997)Google Scholar; Ellingson, Tanja, “Colorful Community or Ethnic Witches-Brew? Multiethnicity and Domestic Conflict during and after the Cold War” Journal of Conflict Resolution 44 (April 2000)Google Scholar; Gurr, Ted, Minorities at Risk: A Global View of Ethnopolitical Conflicts (Washington, D.C.: U.S. Institute of Peace, 1993)Google Scholar; Henderson and Singer (fn. 11); Henderson (fn. 5), chap. 5.

³⁴ See Mitchell, B., European Historical Statistics, 1750–1970 (London: Macmillan, 1975)CrossRefGoogle Scholar, B6, B7.

³⁵ For the statistics, see Bemhardi, Friedrich von, Germany and the Next War (New York: Longmans, 1914)Google Scholar, 243–44.

³⁶ Bill Bishop, “Who Goes to War,” Washington Post, November 16, 2003. After this article was submitted for review, demographic data were released by the Pentagon, confirming the trend: Ann Scott Tyson, “Youths in Rural U.S. Are Drawn to Military,” Washington Post, November 10, 2005. Despite its title, this article emphasizes the recruits' poor economic background (a significant point to be sure) but not their rural roots.

³⁷ Rosecrance (fn. 23), xii and also 26 for the other major industrial countries; Gilpin, Robert, The Challenge of Global Capitalism (Princeton: Princeton University Press, 2000), 33Google Scholar.

³⁸ For the Soviets, see Beevor, Anthony, The Fall of Berlin 1945 (New York: Penguin, 2003), 410Google Scholar. For the Americans and Japanese in World War II, see Goldstein, Joshua, War and Gender: How Gender Shapes the War System and Vice Versa (New York: Cambridge University Press, 2001), 337Google Scholar, 346, respectively.

³⁹ Moller, Herbert, “Youth as a Force in the Modern World,” Comparative Studies in Society and History 10 (April 1967–1968)Google Scholar; Mesquida, Christian and Wiener, Neil, “Human Collective Aggression: A Behavioral Ecology Perspective,” Ethology and Sociobiology 17, no. 4 (1996)CrossRefGoogle Scholar.

⁴⁰ Mitchell (fn. 33), sec. B2, esp. 37, 52; United Nations, World Population Prospects: The 2000 Revision (New York: UN, 2001)Google Scholar.

⁴¹ Huntingdon, Samuel, The Clash of Civilizations and the Remaking of World Order (New York: Simon and Schuster, 1997), 116–20Google Scholar.

⁴² Mitchell (fn. 33), sec. B2, esp. 37, 52. Edward Luttwak argues that with fewer children per family, parents are much more reluctant to accept the loss of children in war; , Luttwak, “Blood and Computers: The Crisis of Classical Military Power in Advanced Postindustrialist Societies,” in Maoz, Zeev and Gat, Azar, eds., War in a Changing World (Ann Arbor: University of Michigan Press, 2001)Google Scholar. This argument does not withstand scrutiny, however; see Azar Gat's critique, also in Maoz and Gat (pp. 88–89).

⁴³ Brandes, Lisa, “Public Opinion, International Security and Gender: The United States and Great Britain since 1945” (Ph.D. diss., Yale University, 1994)Google Scholar.

⁴⁴ Russet, Bruce, “The Democratic Peace—And Yet It Moves,” in Brown, M., Lynn-Jones, S., and Miller, S., eds., Debating the Democratic Peace (Cambridge: MIT, 1996), 340Google Scholar; Doyle, “Michael Doyle on the Democratic Peace—Again,” in Brown, Lynn-Jones, and Miller (p. 372).

⁴⁵ Tessler, Mark and Warriner, Ina, “Gender, Feminism, and Attitudes toward International Conflict: Exploring Relationship with Survey Data from the Middle East” World Politics 49 (January 1997)CrossRefGoogle Scholar; Tessler, Mark, Nachtwey, Jodi, and Grant, Audra, “Further Tests of the Women and Peace Hypothesis: Evidence from Cross-National Survey Research in the Middle East” International Studies Quarterly 43 (September 1999)CrossRefGoogle Scholar.

⁴⁶ I stand between the two poles represented by Mueller (fn. 27); and Creveld, Martin van, The Transformation of War (New York: Free Press, 1991)Google Scholar.

⁴⁷ Knock, Thomas, To End All Wars: Woodrow Wilson and the Quest for a New World Order (New York: Oxford University Press, 1992), 26–28Google Scholar; and generally, Smith, Tony, America's Mission: The United States and Worldwide Struggle for Democracy in the Twentieth Century (Princeton: Princeton University Press, 1994)Google Scholar, chap. 3.

⁴⁸ Cf. very similarly Fukuyama, Francis, State Building: Governance and World Order in the Twenty-first Century (Ithaca, N.Y.: Cornell University Press, 2004), 38–39Google Scholar, 92–93.