This edited volume aims to reveal the Janus-faced character of federalism in the European Union. Federalism appears in two main forms in the EU. On the one hand, numerous formerly unitary Member States have embarked on a path towards a (quasi-)federal governance structure. On the other hand, the EU itself is sometimes qualified as a federal system. Significantly, the concept of federalism has a very different, even opposite, connotation in both contexts. When associated with Member State reform, federalism is regarded as a technique for accommodating autonomy claims of sub-state nations. By contrast, when federalism is used as a label for the EU itself, it is conceived as a far-reaching way of integrating the nations of Europe. This dual appearance of federalism in the EU context is central to the structure of the book. The focus of a first collection of essays is on domestic federalisation processes, more particularly on the impact of these processes on EU law and vice versa. In a second set of contributions, the attention shifts to the question as to whether the EU itself can be described as a federal system, and whether it can learn from existing federations.

Elke Cloots is a Researcher at the University of Leuven and a Fellow of the Research Foundation-Flanders.Geert De Baere is Assistant Professor of International Law and EU Law at the University of Leuven, and senior member of the Leuven Centre for Global Governance Studies.Stefan Sottiaux is Assistant Professor of Constitutional Law and Discrimination Law at the University of Leuven.