World Politics

Research Article

Interstate Peacekeeping: Causal Mechanisms and Empirical Effects

Virginia Page Fortnaa1*

a1 Columbia University

Peacekeeping is perhaps the international community's most important tool for maintaining peace in the aftermath of war. Its practice has evolved significantly in the past ten or fifteen years as it has been used increasingly in civil wars. However, traditional peacekeeping between states is not well understood. Its operation is undertheorized and its effects undertested. This article explores the causal mechanisms through which peacekeepers keep peace and examines its empirical effects after interstate wars. To take the endogeneity of peacekeeping into account, it also examines where peacekeepers tend to be deployed. Duration analysis shows that, all else equal, peacekeeping significantly increases the chances that peace will last. Peacekeepers can help adversaries to maintain peace by making surprise attack more difficult, by reducing uncertainty about enemy intentions, and by preventing and controlling accidents and incidents that can spiral back to war.

Virginia Page Fortna is an assistant professor of political science at Columbia University. Her research is on the duration of peace and war termination in both interstate and civil conflicts. She is the author of Peace Time: Cease-Fire Agreements and the Durability of Peace (2004) and is currently working on a manuscript on peacekeeping in civil wars.

* The author owes debts of gratitude to more people than can be listed here for help and feedback with the project of which this article is a part. She thanks, in particular, Nisha Fazal, Hein Goemans, Lise Howard, Bob Jervis, Bob Keohane, Lisa Martin, Jack Snyder, Alan Stam, Barb Walter, and Suzanne Werner. This research was made possible by grants from the Center for International Security and Cooperation at Stanford, the Carnegie Corporation of New York, and the American Academy of Arts and Sciences.