In the aftermath of war, what determines whether peace lasts or fighting resumes, and what can be done to foster durable peace? Drawing on theories of cooperation, I argue that belligerents can overcome the obstacles to peace by implementing measures that alter incentives, reduce uncertainty about intentions, and manage accidents. A counterargument suggests that agreements are epiphenomenal, merely reflecting the underlying probability of war resumption. I test hypotheses about the durability of peace using hazard analysis. Controlling for factors (including the decisiveness of victory, the cost of war, relative capabilities, and others) that affect the baseline prospects for peace, I find that stronger agreements enhance the durability of peace. In particular, measures such as the creation of demilitarized zones, explicit third-party guarantees, peacekeeping, and joint commissions for dispute resolution affect the duration of peace. Agreements are not merely scraps of paper; rather, their content matters in the construction of peace that lasts.
Virginia Page Fortna is Assistant Professor of Political Science at Columbia Unversity, New York, New York. She can be reached at firstname.lastname@example.org.