In the post-Lisbon era and especially since the outburst of the financial and European sovereign debt crisis, the EU has been changing significantly, to the extent that the meaning and the process of integration are being affected. While constitutional asymmetry is a longstanding feature of the EU polity, the real challenge today is the expanding scope and fragmented character of newly established forms of flexibility, and how they are being used politically. The flexible configuration of integration reinforces a trend toward fragmented integration. Flexibility within the EU could become an end in itself, a device to serve a wide range of strategic visions and preferences in sectoral politics.
Keywords: differentiated integration, acquis communautaire, economic governance, enhanced cooperation, accession policy