Democracy, war effort, and the systemic democratic peace

This article uses an agent-based model and Selectorate Theory to explore the micro-foundations of the systemic democratic peace. Leaders engage in an international bargaining game that can escalate to conflict. Upon resolving the dispute, leaders distribute winnings to domestic constituencies and stand for reselection. The model’s assumptions about selectorate size in a democracy versus an autocracy make democratic leaders more accountable than autocrats and endogenously generates the dyadic democratic peace. The model shows no evidence of an autocratic peace, as mixed dyads are less likely to go to war than autocratic dyads. I further show that democratic leaders invest more resources in wars than predicted by the Nash equilibrium and also more than autocrats. This overinvestment by democratic leaders results in democracies winning more wars than autocrats. This model thus reinforces previous findings that democratic leaders respond to domestic reselection incentives by using more resources in conflict to gain a war-fighting advantage and help ensure victory. Finally, consistent with empirical results, I show that increasing the percentage of democracies in the system does not have a linear effect on the amount of conflict in the system. Below a certain threshold, increasing democracy has no effect on conflict, while after this threshold conflict decreases.