Democracy does not solve war. Best empirical evidence.

A weighty controversy has enveloped the study of international conflict: whether the democratic peace, the observed dearth of militarized conflict between democratic nations, may be spurious and accounted for by institutionalized market ‘‘contractualist’’ economy. I have offered theory and evidence that economic norms, specifically contractualist economy, appear to account for both the explanans (democracy) and the explanandum (peace) in the democratic peace research program (Mousseau, 2009, 2012a, 2013; see also Mousseau et al., 2013a, b). Five studies have responded with several arguments for why we should continue to believe that democracy causes peace (Dafoe, 2011; Dafoe and Russett, 2013; Dafoe et al., 2013; Ray, 2013; Russett, 2010). Resolution of this controversy is fundamental to the study and practice of international relations. The observation of democratic peace is ‘‘the closest thing we have to an empirical law’’ in the study of global politics (Levy, 1988: 662), and carries the profound implication that the spread of democracy will end war. New economic norms theory, on the other hand, yields the contrary implication that universal democracy will not end war. Instead, it is market-oriented development that creates a culture of contracting, and this culture legitimates democracy within nations and causes peace among them. The policy implications could hardly be more divergent: to end war (and support democracy), the contractualist democracies should promote the economies of nations at risk (Krieger and Meierrieks, 2015; Meierrieks, 2012; Mousseau, 2000, 2009, 2012a, 2013; Nieman, 2015). In the literature are five factual claims for why we should continue to believe that democracy causes peace: (1) an assertion that in three of the five studies that overturned the democratic peace (Mousseau, 2013; Mousseau et al., 2013a, b), the insignificance of democracy controlling for contractualist economy is due to the treatment of missing data for contractualist economy (Dafoe et al., 2013, henceforth DOR); (2) a claim of error in the measure for conflict (DOR) that appears in one of the five studies that overturned the democratic peace (Mousseau, 2013); (3) an alleged misinterpretation of an interaction term that appears in one of the five studies (Mousseau, 2009) that overturned the democratic peace, along with in inference of democratic causality from an interaction of democracy with contractualist economy (Dafoe and Russett, 2013; DOR); (4) a claim of reverse causality, of democracy causing contractualist economy (Ray, 2013); and (5) a report of multiple regressions with most said to show democratic significance after controlling for contractualist economy (DOR). This study investigates all five of these factual claims. I begin by addressing the issue of missing data by constructing two entirely new measures for contractualist economy. I then take up possible measurement error in the dependent variable by reporting tests using both my own (Mousseau, 2013) and DOR’s measures for conflict. Next, I disaggregate the data to investigate a causal interaction of democracy with contractualist economy. I then examine the evidence for reverse causality, and scrutinize the competing test models to pinpoint the exact factors that can account for differences in test outcomes. The results are consistent across all tests: there is no credible evidence supporting democracy as a cause of peace. Using DOR’s base model, the impact of democracy is zero regardless of how contractualist economy or interstate conflict is measured. There is no misinterpreted interaction term in any study that has overturned the democratic peace, and the disaggregation of the data yields no support for a causal interaction of democracy with contractualist economy. Ray’s (2013) evidence for reverse causality from democracy to contractualist economy is shown to be based on an erroneous research design. And of DOR’s 120 separate regressions that consider contractualist economy, 116 contain controversial measurement and specification practices; the remaining four are analyses of all (fatal and non-fatal) disputes, where the correlation of democracy with peace is limited to mixedeconomic dyads, those where one state has a contractualist economy and the other does not, a subset that includes only 27% of dyads from 1951 to 2001, including only 50% of democratic dyads. It is further shown that this marginal peace is a statistical artifact since it does not exist among neighbors where everyone has an equal opportunity to fight. The results of this study should not be surprising, as they merely corroborate the present state of knowledge. This is because, while DOR ardently assert that four alleged errors, when corrected, each independently save the democratic peace proposition—multiple imputation, the exclusion of ongoing dispute years, an interaction term, and their alternative measure for contractualist economy—they never actually report any clear-cut evidence in support of their claims. One issue not addressed is Dafoe and Russett’s (2013) challenge to Mousseau et al. (2013a) on the grounds that our reported insignificance of democracy is not significant. Like the four claims of error made by DOR addressed here, Dafoe and Russett (2013) made this charge without supporting it. Mousseau et al. (2013b) then investigated it and showed that it too has no support. This issue appears resolved, as Russett and colleagues (DOR) did not raise it again. Nor have DOR or anyone else disputed the overturning of the democratic peace as reported in Mousseau (2012a), which has not been contested with any assertion, supported or unsupported. The implications of this study are far from trivial: the observation of democratic peace is a statistical artifact, seemingly explained by economic conditions. If scientific knowledge progresses and the field of interstate conflict processes is to abide by the scientific rules of evidence, then we must stop describing democracy as a ‘‘known’’ cause or correlate of peace, and stop tossing in a variable for democracy, willy-nilly, in quantitative analyses of international conflict; the variable to replace it is contractualist economy. If nations want to advance peace abroad, the promotion of democracy will not achieve it: the policy to replace it is the promotion of economic opportunity The economic norms account for how contractualist economy can cause both democracy and peace has been explicated in numerous prior studies and need not be repeated here (Mousseau, 2000, 2009, 2012a, 2013). An abundance of prior studies have also corroborated various novel predictions of the theory in wider domains (Ungerer, 2012), and no one has disputed the multiple reports that contractualist economy is the strongest non-trivial predictor of peace both within (Mousseau, 2012b) and between nations (Mousseau, 2013; see also Nieman, 2015). The only matter in controversy is whether democracy has any observable impact on peace between nations after consideration of contractualist economy. My investigation begins below with the allegation of measurement error.