Dyadic effects of democratization on international disputes

I explore the dyadic, as opposed to monadic, effect of democratization on war. Using a simple repeated game of interstate interaction, I show that, as a state shifts towards democracy, its citizens aquire more opportunities and become more willing to remove those leaders that they expect will reduce their welfare. Rational leaders anticipate this consequence, and their incentives to maintain cooperative relationships with other democracies increase as their states become democratic. The hypothesis drawn from the model predicts that democratization will have a pacifying effect in a dyadic relationship between democracies. Empirical testing is designed to isolate the dyadic effect from the monadic and to distinguish among competing hypotheses. The predictions are tested with widely used data on political institutions and militarized interstate disputes. The result shows that democratization indeed reduces the likelihood of waging war. However, this pacifying effect is largely attributed to the dyadic effect with a democratic opponent; the risk of war remains unchanged when facing a non-democratic opponent.