Some of the most innovative scholars in the field of European constitutionalism highlight different facets of the new constitutional discussion. Provoking deep analysis of the different ideas of constitution and constitutionalism, their study delineates new ways of thinking about the future of Europe. In particular, it challenges the European Union as an evolving federal polity. This book will appeal to anyone interested in the subject of constitutionalism, students as well as professionals in law, politics and philosophy.