The institutional architecture of the EU and its role in the world, as well as peoplesÃ alienation and dissatisfaction with the EU, are primary reasons why it makes sense to rethink the legal and political structure of the EU. Even if there is a wide academic agreement that the EU could better be understood in the framework of federalism, there is still a lack of comprehensive study on the EU from a perspective of comparative federalism. This book demonstrates that a federal structure could be an appropriate institutional and constitutional response to the EU challenges. The EU develops as a federal polity with an institutional-federal pact. It combines dual and cooperative federalism, based on examples of successful federations without achieving a traditional federation.