Towards a Continuous Specification of the Democracy-Autocracy Connection

It has recently been argued that apparent peace between democracies may be the result of political similarity rather than joint democracy, and that there may exist an “autocratic peace” which is similar to the democratic peace. If political similarity generally is the cause of peace rather than joint democracy specifically, then the democratic peace is merely a statistical artifact that follows from separating out a selected subset of data. In addition, we do not know whether the autocratic peace or democratic peace is stronger, if they both exist. Existing empirical specifications of the connection between joint regime type and international conflict have not been adequate to assess these arguments. I develop a specification of joint regime-type variables that uses continuous measures without arbitrary cutoffs and allows us to assess a larger set of hypothesized regime-type effects. I find that jointly democratic and jointly autocratic pairs of states are both less conflict prone than other pairings, but that political similarity apart from these extremes has a much smaller effect on the risk of conflict. The results suggest that political similarity between coherent regimes (those at extremes of the institutionalized democracy-autocracy scale) encourages dyadic peace. But although there is a lower risk of conflict in both jointly democratic and jointly autocratic dyads, I find that the democratic peace is clearly stronger than the autocratic peace. Note: I would like to thank Glenn Palmer and Bruce Russett for helpful comments, and Andreea Mihalache and Matthew Rupert for research assistance. Replication data, sensitivity analyses, and graphs in color are available at the author’s web site at http://www.personal.psu.edu/dsb10. INTRODUCTION Over the past few years, scholars examining the so-called “democratic peace” have noted the possible complementary existence of an “autocratic peace.” Most recently, in the American Political Science Review, Peceny, Beer, and Sanchez-Terry (2002) argued explicitly for what they refer to as a “dictatorial peace.” Scholars of international relations have in fact noted the apparent existence of such a peace for several years (e.g., Gleditsch and Hegre, 1997; Oneal and Russett, 1997; Raknerud and Hegre, 1997; Beck and Jackman, 1998; Nordstrom, 2000; Werner, 2000; Bennett and Stam, 2004). But although the apparent existence of this alternative peace has been noted, theoretical arguments for why it should exist, and empirical analyses that reveal more detail of it, have been underdeveloped. In this article I explore the empirical relationship between the “two peaces” by developing an analytic specification that can help us answer important questions about how the autocratic peace relates to the democratic peace. The development of theoretical arguments for why an autocratic peace may exist has lagged behind the empirical observation of its presence (much as in the early days of the democratic peace literature), with Werner (2000) and Peceny et al. (2002) being the two primary works offering significant theoretical discussion of the autocratic peace vis-à-vis the democratic peace. More importantly for this article, although empirical work has observed that an autocratic peace exists, it has lagged in not examining precisely what the autocratic peace looks like in relation to the democratic peace. If the autocratic peace is stronger than the democratic peace, for instance (if the probability of conflict is lower between two autocracies than between two democracies), then it suggests we rethink the desirability of the democratic peace (at least on purely pragmatic conflict grounds). Alternatively, if only a narrow and identifiable set of autocratic states are more peaceful than a broad range of democracies, then this suggests a new pattern to be further explained. And if both the autocratic and democratic peaces can be subsumed empirically under the broader category of “political similarity peace,” then we should be looking for a single broad theoretical formulation. However, analyses of the regime type-conflict relationship have not used a statistical specification that can adequately reveal details of the comparative