Replication Data for: The Limited Scope of the Democratic Peace: What We Are Missing

The democratic peace program arguably constitutes one of the most successful empirical research programs in the discipline. Its main empirical finding motivated extensive theorizing (e.g., challengers, as well as distinct theoretical enterprises), sparked further debate about how to conceptualize and operationalize democracy, and shifted the foreign policy discourse, particularly in the United States. Lost in these successes, however, is a critical unanswered question: how much interstate peace can the democratic peace potentially explain? We explore these limits (i.e., scope, or empirical coverage) in this study. We first identify the peaceful dyadic relationships—namely those that never go to war across long historical periods. We next classify these dyads as democratic (i.e., both members are democracies) or non-democratic. The empirical analysis then examines this democracy-peace relationship across three time periods, three distinct samples (which address potential false positives), two definitions of ‘peace’, and two thresholds for democracy. Regardless of how we approach the data, only 4-26% of all peaceful dyads qualify as ‘democratic’. Because we control for the obvious trivial explanation (i.e., insufficient capabilities), some other (set of) factor(s) must account for the majority of interstate peace. We close with discussion about where future research might search for these factors, as well as the larger policy implications of the study.