Earlier versions of this paper were presented at the 1999 Annual Meeting of the American Political Science Association, September 1-5, Atlanta, GA, and the 2000 Annual Meeting of the Midwest Political Science Association, April 27-30, Chicago, IL. The authors thank Steffen Ganghof, Philip Genschel, Mark Hallerberg, Alex Hicks, William Keech, Dennis Quinn, and the anonymous reviewers and editor ...