The evolving European systems of governance, in particular the European Union, challenge and transform the state, the most important locus of governance and political identity over the last 200 years. The series Themes in European Governance aims to publish the best theoretical and analytical scholarship on the impact of European governance on the core institutions, policies and identities of nation-states. It focuses on central themes such as citizenship, welfare, political decision-making, and economic, monetary and fiscal policies. An initiative of Cambridge University Press and the Programme on Advanced Research on the Europeanisation of the Nation-State (ARENA), Norway, the series includes contributions in the social sciences, humanities and law. The series aims to provide theoretically-oriented, empirically-informed studies analysing key issues both at the European level and within European states. Volumes in the series will be of interest to scholars and students of Europe within Europe and worldwide. It will be of particular relevance to those interested in the development of the sovereignty and governance of European states, and in the issues raised by multi-level governance and multi-national integration throughout the world.