Differentiated Integration or Differentiated Implementation? Application to EU Immigration Policy

Even before the Brexit discussions hit Europe, different studies have indicated the existence of differentiated policy outcomes in both policy-making and implementation of EU law. Firstly, the member states do not equally participate in all EU policies with countries enjoying opt-outs or being temporarily excluded from particular areas. Some countries fully participate in given policy areas, even though they are not EU members. Secondly, implementation could result in different policy outcomes where governments and frontline implementers fully transpose and implement the EU requirements (compliant implementation) or fail to do so altogether (non-compliant implementation). In addition, frontline implementers may not implement the transposed EU provisions (decoupled implementation) or may implement EU policies that are not even transposed in national legislation (informal implementation). However, it is an unsettled question how varying levels of participation in the EU relate to different implementation outcomes. To address this gap, I analyze the implementation of two directives (Directive 2008/115/EC on the return of illegal immigrants and Directive 2004/82/EC on air passenger information). The findings indicate that the consequences of differentiated integration on domestic outcomes depend the participation incentives by national governments and capacities of frontline implementers. Thus, low-capacity member states excluded from certain policy areas (Bulgaria, Romania and Cyprus) exhibit the lowest levels of non-compliant implementation, but also reveal the highest levels of decoupled implementation. Conversely, high-capacity opting-out member states (the UK) and non-EU countries (Switzerland, Norway, Iceland) often experience non-compliant implementation, but also engage in informal implementation.