Peace and Democracy

Peace and regime type can be examined at the dyadic, nation, and system levels. At the dyadic level, it is well established that democracies rarely if ever fight each other. At the national level, the broad consensus is that there is no significant relationship between democracy and war participation, but this conclusion remains controversial. At the system level, there has been little research; most scholars have taken for granted that the answer can be inferred from the findings at the dyadic or national levels. The authors show that, if the conventional wisdom holds at the dyadic and national levels, the probability of war in a politically mixed dyad must be higher than the probability of war between two nondemocracies, and the relationship between democracy and war at the system level must be parabolic. Thus increasing democratization initially produces more war, and the reduction of war starts only at a higher level of democratization.