From a Europe of bits and pieces to a union of variegated differentiation

Thirty years after the Europe of bits and pieces of the Maastricht Treaty, the EU legal system has evolved beyond fragmentation to accommodate institutionally structured forms of differentiation. This paper explores several types of new differentiation regimes and argues that they can coexist together without necessarily challenging the unity of the EU legal system. It analyses how the legal system has progressively been adapting to new integration pathways by internalising differentiation and reabsorbing the fragmentation of the Maastricht’s construction. Through the analysis of the Court’s jurisprudence and two case-studies in the areas of economic governance and defence it shows how different strands of differentiation can be blended together in ‘coherent’ differentiated regimes. The paper also considers future differentiation pathways after Brexit and emerging concerns as regards legitimacy and democratic accountability of a differentiated Union