A previous version of this paper was presented at the 4th meeting of the European Consortium on Political Research’s Standing Group on International Relations, Canterbury, UK, September 2001. This paper was first drafted during a Council on Foreign Relations International Affairs Fellowship. Elizabeth DeSombre, A. Cooper Drury, Charles Glaser, Jon Hovi, Sean Jones, John Mearsheimer, Emerson Niou, Bob Pape, Duncan Snidal, and Han Dorussen provided valuable comments and suggestions. I am particularly grateful to Kimberly Elliott for making her data accessible to me. Michael Cohen’s assistance was invaluable during the drafting process. The usual caveat applies.