Regional regimes – authoritative arrangements facilitating economic integration in a particular region – have sprouted across the globe in recent decades. More than fifty such arrangements currently exist, among them the European Union (EU) and the North American Free Trade Agreement (NAFTA). They are an important – perhaps the most important – form in which competencies, formerly the preserve of sovereign states, have been rebundled. Yet there is no sign of convergence in the policy scope and institutional depth of such regional regimes. In this chapter, we argue that such variation has a decisive effect on their political support. So, to extend Sidney Tarrow's line of argument in Chapter 3, rebundling of authority may shape group support and opposition as well as the strategies that groups adopt to achieve their objectives.

Our focus is on mainstream left political parties in the member states of the EU and NAFTA. Political parties are vital in building regional regimes. When Jean Monnet built his Action Committee for the United States in Europe from the mid-1950s, he sought above all to gain the support of socialists and unions, because he regarded these groups as critical to the future of European integration. He realized that the European Community was a political, not merely a functional, project, and that its future would depend on the support it could muster from political parties and mass organizations (Duchêne 1994: 285ff).