168 ERIK GARTZKE and Schumpeter,favoring Kantian republicanism.?Levy saw constitutional constraints as inhibiting the sovereign's (1988)characterized the democratic peace as"lawlike",s innate proclivity toward warfare.Norms explanations as- anticipating the bulk of quantitative research.Numerous sign an analogous role to informal processes said to evolve studies have now reported a negative statistical association in mature democracies(Dixon 1993,1994;Ember,Ember, between dyadic democracy and disputes,crises,or wars, and Russett 1992;Mintzand Geva 1993;Owen 1994,1997; especially in the post-World War II period(Beck,Katz, Russett 1993).12 Constructivists argue that warfare is be- and Tucker 1998;Bremer 1992,1993;Gelpi and Griesdorf coming socially unacceptable(Cederman 2001a,2001b; 1997;Gleditsch 1995;Gleditsch and Hegre 1997;Gleditsch Cederman and Rao 2001;Mueller 1989;Risse-Kappen and Ward 1997;Hensel,Goertz,and Diehl2000;Hermann 1995,1997;Wendt 1999).13 Some see the evolution of and Kegley 1995,1996;Hewitt and Wilkenfeld 1996; a common identity (Deutsch 1978;Flynn and Farrell Huth and Allee 2002,2003;Maoz and Abdoladi 1989; 1999).14 Others claim that mature democracies do not Maoz and Russett 1992,1993;Morgan and Campbell go to war with states that they perceive as democratic,but 1991;Morgan and Schwebach 1992;Oneal and Russett may fight with unrecognized democracies(Weart 1994, 1997,1999a,1999c;Oneal,Russett,and Berbaum 2003; 1998).15 Oneal et al.1996;Raknerud and Hegre 1997;Ray 1993, Constraint theories have been criticized as ad hoc and 1995;Russett 1993;Russett and Oneal 2001;Russett, deductively flawed(Bueno de Mesquita et al.1999;Gates, Oneal,and Davis 1998;Senese 1997;Van Belle 1997;Ward Knutsen,and Moses 1996;Layne 2003;Rosato 2003).Note and Gleditsch 1998;Weede 1992).10 that the statement"democracies behave differently toward Theories of democratic peace have also proliferated, each other than toward nondemocracies"characterizes, in no small part because of the difficulty in accounting in broad strokes,both the observation and many of the for the special dyadic nature of the observation.1 Ini- theories designed to explain the observation.Efforts to tial accounts focused on linking domestic liberal norms avoid a circularity between theory and evidence benefit or institutions to constraints on the use of force.Institu- most from new empirical content(Huth and Allee 2003). tional explanations assert that elements of the apparatus Work by Mousseau(2000),Hegre(2000),and Mousseau, of liberal government interfere with the exercise of mili- Hegre,and Oneal(2003),for example,restricts the do- tary foreign policy(Bueno de Mesquita and Lalman 1992; main of the democratic peace to states with advanced Maoz and Russett 1993;Russett 1993).Kant (17951957) industrialized economies.It is not obvious from existing explanations for the democratic peace why norms,insti- 7Doyle chooses Schumpeter(1950,1955)because his views differ tutions,or other factors would inhibit conflict among rich from the tradition of liberal political economy and because he "saw the interaction of capitalism and democracy as the foundation of democracies but fail to do so for poor democratic states.16 liberal pacifism"(Doyle 1986,1152).Thus,even Doyle's attempt Bueno de Mesquita et al.(1999,2003)offer an elab- at synthesis assumes away an independent effect of capitalism on orate and carefully constructed explanation in which peace. 8Waltz asserts that "theories explain laws"(1979,6),suggesting a need in international relations for more laws or fewer theories. Part of the intellectual appeal of the democratic peace is that it is 2Old democratic dyads appear about as dispute prone as newer dyads(Enterline 1998;Ward and Gleditsch 1998) something to explain. For reviews,seeChan(1993,1997),Gleditsch(1992),Maoz(1997), 13Kaysen(1990)offers a critique of Mueller's theory and an under- appreciated perspective on the liberal peace. Morgan(1993),and Ray(1997,1998,2000). Several authors claim that the democratic peace relationship ex- The argument potentially applies to autocratic regimes with a common identity (Peceny,Beer,and Sanchez-Terry 2002). isted in the nineteenth century(Gochman 1997;Oneal and Russett 1999c;Tucker 1997).Others find evidence in the Italian Renaissance 15Liberal leaders(or populations)can also intentionally downplay (Sobek 2003)or classical Greece (Weart 1994,1998).Russett and the“democraticness”of another regime(Oren 1995).“Simply be- Antholis (1992)and Russett (1993,chapter 3)identify the "frag- cause it won the votes of a desperate people is no reason to grant ile emergence"(1993,43)of norms of democratic cooperation, even the slightest scrap of legitimacy...to Hamas"(Mortimer B. though Bachteler(1997)views Delian cooperation as a product of Zukerman,U.S.News and World Report,February 13,2006,page Athenian hegemony (see also Russett 1997).Dixon,Mullenbach, 63). and Carbetta (2000)suggest that democratic peace arises in the twentieth century.Hewitt and Young(2001)date the origins of the 16Mousseau(2003)argues that capitalism creates a culture of con- democratic peace at somewhere between 1924(for wars)and 1930 tracts,which then conditions democratic peace.Strangely,his anal- (for MIDs).For additional debate about the ancient evidence,see ysis focuses on an interaction term between democracy and eco- Robinson(2001a,2001b)and Weart(2001). nomic development,rather than examining free market activity, laissez-faire policies,or the availability or enforceability of con- "The growing consensus that democracies rarely ifever fight each tracts.Trading democracies should presumably also be affected, other is not matched by any agreement as to how best to explain this since trade involves extensive contracting.However,Mousseau, strong empirical regularity(Levy 2002,359).Lipson quips about Hegre,and Oneal report that the interaction term between democ- the democratic peace that "We know it works in practice.Now we racy and trade dependence is statistically insignificant(2003,Table have to see if it works in theory!"(2005,1). 2,296).168 ERIK GARTZKE and Schumpeter, favoring Kantian republicanism.7 Levy (1988) characterized the democratic peace as “lawlike”,8 anticipating the bulk of quantitative research.9 Numerous studies have now reported a negative statistical association between dyadic democracy and disputes, crises, or wars, especially in the post–World War II period (Beck, Katz, and Tucker 1998; Bremer 1992, 1993; Gelpi and Griesdorf 1997; Gleditsch 1995; Gleditsch and Hegre 1997; Gleditsch and Ward 1997; Hensel, Goertz, and Diehl 2000; Hermann and Kegley 1995, 1996; Hewitt and Wilkenfeld 1996; Huth and Allee 2002, 2003; Maoz and Abdoladi 1989; Maoz and Russett 1992, 1993; Morgan and Campbell 1991; Morgan and Schwebach 1992; Oneal and Russett 1997, 1999a, 1999c; Oneal, Russett, and Berbaum 2003; Oneal et al. 1996; Raknerud and Hegre 1997; Ray 1993, 1995; Russett 1993; Russett and Oneal 2001; Russett, Oneal, and Davis 1998; Senese 1997; Van Belle 1997; Ward and Gleditsch 1998; Weede 1992).10 Theories of democratic peace have also proliferated, in no small part because of the difficulty in accounting for the special dyadic nature of the observation.11 Ini￾tial accounts focused on linking domestic liberal norms or institutions to constraints on the use of force. Institu￾tional explanations assert that elements of the apparatus of liberal government interfere with the exercise of mili￾tary foreign policy (Bueno de Mesquita and Lalman 1992; Maoz and Russett 1993; Russett 1993). Kant ([1795]1957) 7Doyle chooses Schumpeter (1950, 1955) because his views differ from the tradition of liberal political economy and because he “saw the interaction of capitalism and democracy as the foundation of liberal pacifism” (Doyle 1986, 1152). Thus, even Doyle’s attempt at synthesis assumes away an independent effect of capitalism on peace. 8Waltz asserts that “theories explain laws” (1979, 6), suggesting a need in international relations for more laws or fewer theories. Part of the intellectual appeal of the democratic peace is that it is something to explain. 9For reviews, see Chan (1993, 1997), Gleditsch (1992), Maoz (1997), Morgan (1993), and Ray (1997, 1998, 2000). 10Several authors claim that the democratic peace relationship ex￾isted in the nineteenth century (Gochman 1997; Oneal and Russett 1999c; Tucker 1997). Others find evidence in the Italian Renaissance (Sobek 2003) or classical Greece (Weart 1994, 1998). Russett and Antholis (1992) and Russett (1993, chapter 3) identify the “frag￾ile emergence” (1993, 43) of norms of democratic cooperation, though Bachteler (1997) views Delian cooperation as a product of Athenian hegemony (see also Russett 1997). Dixon, Mullenbach, and Carbetta (2000) suggest that democratic peace arises in the twentieth century. Hewitt and Young (2001) date the origins of the democratic peace at somewhere between 1924 (for wars) and 1930 (for MIDs). For additional debate about the ancient evidence, see Robinson (2001a, 2001b) and Weart (2001). 11“The growing consensus that democracies rarely if ever fight each other is not matched by any agreement as to how best to explain this strong empirical regularity” (Levy 2002, 359). Lipson quips about the democratic peace that “We know it works in practice. Now we have to see if it works in theory!” (2005, 1). saw constitutional constraints as inhibiting the sovereign’s innate proclivity toward warfare. Norms explanations as￾sign an analogous role to informal processes said to evolve in mature democracies (Dixon 1993, 1994; Ember, Ember, and Russett 1992; Mintz and Geva 1993; Owen 1994, 1997; Russett 1993).12 Constructivists argue that warfare is be￾coming socially unacceptable (Cederman 2001a, 2001b; Cederman and Rao 2001; Mueller 1989; Risse-Kappen 1995, 1997; Wendt 1999).13 Some see the evolution of a common identity (Deutsch 1978; Flynn and Farrell 1999).14 Others claim that mature democracies do not go to war with states that they perceive as democratic, but may fight with unrecognized democracies (Weart 1994, 1998).15 Constraint theories have been criticized as ad hoc and deductively flawed (Bueno de Mesquita et al. 1999; Gates, Knutsen, and Moses 1996; Layne 2003; Rosato 2003). Note that the statement “democracies behave differently toward each other than toward nondemocracies” characterizes, in broad strokes, both the observation and many of the theories designed to explain the observation. Efforts to avoid a circularity between theory and evidence benefit most from new empirical content (Huth and Allee 2003). Work by Mousseau (2000), Hegre (2000), and Mousseau, Hegre, and Oneal (2003), for example, restricts the do￾main of the democratic peace to states with advanced industrialized economies. It is not obvious from existing explanations for the democratic peace why norms, insti￾tutions, or other factors would inhibit conflict among rich democracies but fail to do so for poor democratic states.16 Bueno de Mesquita et al. (1999, 2003) offer an elab￾orate and carefully constructed explanation in which 12Old democratic dyads appear about as dispute prone as newer dyads (Enterline 1998; Ward and Gleditsch 1998). 13Kaysen (1990) offers a critique of Mueller’s theory and an under￾appreciated perspective on the liberal peace. 14The argument potentially applies to autocratic regimes with a common identity (Peceny, Beer, and Sanchez-Terry 2002). 15Liberal leaders (or populations) can also intentionally downplay the “democraticness” of another regime (Oren 1995). “Simply be￾cause it won the votes of a desperate people is no reason to grant even the slightest scrap of legitimacy ... to Hamas” (Mortimer B. Zukerman, U.S. News and World Report, February 13, 2006, page 63). 16Mousseau (2003) argues that capitalism creates a culture of con￾tracts, which then conditions democratic peace. Strangely, his anal￾ysis focuses on an interaction term between democracy and eco￾nomic development, rather than examining free market activity, laissez-faire policies, or the availability or enforceability of con￾tracts. Trading democracies should presumably also be affected, since trade involves extensive contracting. However, Mousseau, Hegre, and Oneal report that the interaction term between democ￾racy and trade dependence is statistically insignificant (2003, Table 2, 296)