In the post-Maastricht era, differentiated integration (DI) has allowed the EU to cope with its deep-seated diversity. DI repeatedly provided a pragmatic institutional fix to reconcile the deepening of integration with a widening membership. In recent years, the driving factors behind DI in the EU have been extensively researched (for instance Schimmelfennig and Winzen 2014, 2019). Our knowledge of the long-term consequences of differentiation, however, has remained more limited. In the latter vein, this paper sets out to explore the consequences of DI for the trajectory of European integration. In doing so, it also draws on evidence from federal states. In the EU, differentiation is a relatively recent phenomenon. By contrast, federations such as Canada, Switzerland and the United States have a much longer history of experimentation with asymmetrical arrangements of different shades. In responding to the above research question, it could hence prove beneficial to link the literature on DI with the longstanding literature on “asymmetrical federalism” (Tarlton 1965; Stevens 1977; Keating 1998; Agranoff 1999). Many scholars of asymmetrical federalism are critical of differentiation’s impact over time. Three such criticisms stand out. First, differentiation is argued to undermine the problem-solving capacity of multilevel systems. Individual opt-outs in redistributive policy fields threaten the solidarity among constituent units upon which multilevel systems thrive. A second criticism frequently levelled against differentiation is that it undermines the democratic legitimacy of a multilevel system. DI produces uncertainty among citizens regarding their legal rights and the avenues of democratic expression at their disposal. DI also calls into question the representativeness of legislative bodies. Third, it is often claimed that initial instances of differentiation spur a desire for further differentiation at later instances. If this were true, differentiation would undercut the long-term stability of multilevel polities. The paper is structured along the lines of these three criticisms. It finds that, while differentiation is a longstanding phenomenon in federal states, strong central-level institutions continuously seek to contain it to singular instances in order to keep its adverse effects at bay. In the EU, where such institutions are missing, the long-term costs of a proliferation of DI could outweigh the initial benefits.
Agranoff, R. (ed.) (1999) Accommodating Diversity: Asymmetry in Federal States, Baden-Baden: Nomos.
Keating, M. (1998) ‘What’s wrong with asymmetrical government?’, Regional and Federal Studies 8(1): 195–218.
Schimmelfennig, F. and Winzen, T. (2014) ‘Instrumental and Constitutional Differentiation in the European Union’, Journal of Common Market Studies 52(2): 354–370.
Schimmelfennig, F. and Winzen, T. (2019) ‘Grand Theories, Differentiated Integration’, Journal of European Public Policy, doi:10.1080/13501763.2019.1576761.
Stevens, R. M. (1977) ‘Asymmetrical Federalism: The Federal Principle and the Survival of the Small Republic’, Publius: The Journal of Federalism 7(4): 177–203.
Tarlton, C. D. (1965) ‘Symmetry and Asymmetry as Elements of Federalism: A Theoretical Speculation’, The Journal of Politics 27(4): 861–874.