Twenty-five years ago, none of us anticipated that regime theory-or the new institutionalism more generally-would develop into a major movement in the study of international relations (Young 1994). Yet in retrospect, it is not hard to identify several factors that converged to bring about this unanticipated occurrence. What many now call neo-liberal institutionalism arose, in part, to explain how cooperation could survive and even thrive at the international level-especially in fields like trade and monetary relations-in the face of the declining capacity of the United States to act as an effective hegemon. As Robert Keohane’s seminal account-set forth in his 1984 book entitled After Hegemonymakes clear, issue-specific regimes can prove beneficial for all parties concerned, whether or not these actors constitute a privileged group in the Olsonian sense.2