Beyond in or Out. Differentiated Implementation as a Way to Manage Diversity in the EU

In the past years, forms of differentiated integration have often been put forward as a way to manage diversity between member states in the EU. This debate and the academic literature on differentiated integration have focused on the adoption of legislation and policies that apply to some member states but not others. Examples in the current EU are the Eurozone, Schengen and the unitary patent regime. This focus neglects another potential way to deal with diversity, the differentiated implementation of EU law and policies. The EU legal and political system explicitly allows room for member states to implement EU law in different ways, for instance through the use of directives, minimum harmonization, optional harmonization and/or vague norms. Arguably, these types of member state discretion in implementation serve the same purposes as differentiated integration, in that they are a way to cope with differences in political preferences as well as differences in cultural, economic, legal and political conditions among member states. Because differentiated implementation occurs under a set of common standards and objectives, it may be able to achieve a more nuanced balance between cooperation and diversity than the ‘in or out’ logic of differentiated integration. At the same time, differences in implementation may also undermine the internal market, make it more difficult to achieve common objectives and deprive citizens of basic rights. For those reasons, uniform implementation still is the norm and ideal among EU policy-makers and in much of the literature. This paper seeks to offer a conceptual framework for thinking more systematically about the potential benefits and disadvantages of differentiated implementation in the EU. It does so by developing a typology of forms of differentiated implementation and by specifying the conditions that affect the trade-off between the costs and benefits of these forms.