David A. Baldwin is senior political scientist at the Princeton School of Public and International Affairs and the Ira D. Wallach Professor Emeritus of World Order Studies at Columbia University. His books include Power and International Relations (Princeton). Ethan B. Kapstein is Arizona Centennial Professor of International Affairs at the School of Public Affairs and Thunderbird School of Global Management at Arizona State University and codirector of the Empirical Studies of Conflict Project at Princeton University. His books include Economic Justice in an Unfair World (Princeton).