Over the past 25 years, Jurgen Habermas has presented what is arguably the most coherent and wide-ranging defence of the project of European unification and of parallel developments towards a politically integrated world society. In developing his key concepts of the transnationalisation of democracy and the constitutionalisation of international law, Habermas offers the main players in the struggles over the fate of the European Union (the politicians, the political parties and the publics of the member states) a way out of the current economic and political crisis, should they choose to...