"United in Diversity"? Differentiated Integration in An Ever Diverse European Union

This contribution analyzes the concept of differentiated integration and its multifarious meanings and applications. After a short historical overview, showing that instances of differentiated integration have existed from the foundation of the European Communities, it focuses on the current phase, which started in the 1990s with the establishment of enhanced cooperation, a general mechanism allowing flexibility in integration among member States. Moreover, it analyzes the areas of the Economic and Monetary Union (EMU), the Schengen Area and the Area of Freedom, Security and Justice, which are among the most important areas where differentiated integration has taken place. The essay develops a set of elements that allow the classification of all these cases in relation to their centripetal or centrifugal effect, i.e. whether they foster or hamper further integration. Finally, it discusses the recent political endorsement of differentiated integration as a solution for the current multidimensional crisis of the European Union, which may be considered as the recognition of the crucial importance of flexibility and pluralism, but also as an indirect acknowledgement of the inability to move forward together, due to the structural divergences among EU member States.