Pugnacious Presidents: Democratic Constitutional Systems and International Conflict

Abstract

How do domestic political institutions affect international conflict? Democratic peace theorists argue that jointly-democratic dyads are less likely to engage in war than other types of states, but these explanations cannot account for the large number of militarized conflicts that fall short of full-scale war among democratic states. We hypothesize that presidential democracies place fewer constraints on the executive’s ability to use force and are, therefore, more likely to engage in international conflict than other types of democratic states. Using standard international relations datasets on conflict, we demonstrate that jointly-presidential democratic dyads are over two times more likely to become involved in militarized interstate disputes than other jointly-democratic dyads. Moreover, we find that when it comes to lower-level conflicts, jointly-presidential dyads are statistically indistinguishable from nondemocratic dyads. These results have important implications for our understanding of democratic peace theory and the causes of international conflict.