The salience of supranational structures of governance in- creased dramatically during the last decade. The World Trade Organization (WTO) and North American Free Trade Agreement (NAFTA), for example, not only establish de- tailed norms, rules, and decision-making procedures but also endow supranational governing boards with sweeping powers of enforcement. The European Monetary Union (EMU) greatly constrains national sovereignty by eliminating na- tional currencies and allowing the European Central Bank to play a key role in national economic policymaking. In his study of NAFTA and the European Monetary System (EMS), Lloyd Gruber contends that international relations scholars have had difficulty coming to grips with the trend toward global governance because the dominant theoretical approaches-neoliberalism and neorealism-tend to assume incorrectly that international cooperation produces mutual benefits for all contracting parties.