Democratic Peace Theory

Abstract

Democratic peace is the proposition that democracies are more peaceful in their foreign relations. This idea dates back centuries, at least to Immanuel Kant and other 18th-century Enlightenment thinkers. In recent decades it has constituted a major research agenda, competing with and arguably supplanting other research agendas such as neo-realism. The democratic peace proposition has many possible empirical and theoretical forms. On the empirical side, some propose that democracies are more peaceful in their relations with all other states in the system (“monadic” democratic peace); some propose that democracies are more peaceful only in their relations with other democracies (“dyadic” democratic peace); others argue that the more democracies there are in a region or the international system, the more peaceful the region or international system will be (“systemic” democratic peace); and still others doubt the existence of any significant relationship between democracy and peace. Notably, most although not all empirical research on the democratic peace has employed quantitative methods of analysis. On the theoretical side, there are many different accounts of the relationship between democracy and peace, with most focusing on domestic political institutions, domestic political norms, and constructed identities. The democratic peace proposition is connected to many other propositions linking domestic politics and international relations, including that democracies are more likely to cooperate with each other, that democracies are more likely to win the wars they fight, that escalating military casualties degrade public support for war, that leaders initiate conflict to secure their domestic hold on power (the diversionary hypothesis), that democracies fight shorter wars, that different kinds of democracies experience different kinds of conflict behavior, that different kinds of authoritarian systems experience different kinds of conflict behavior, and others. The democratic peace also overlaps with related ideas such as the liberal peace and the commercial peace.