ABSTRACT
The EU is marked by inherent diversity of its Member States. This is reflected at the constitutional level, causing constitutional conflicts between the European Union’s and the Member States’ constitutional norms. These constitutional conflicts may be resolved by resorting to differentiation. Different mechanisms of differentiation can be used to accommodate constitutional diversity without undermining the effectiveness of European Union law. Differentiation has already been adopted for that purpose as EU law allows the Member States to be treated differently or apply EU law differently due to national constitutional norms. Since this approach is already prevalent in other areas of EU law, it should a fortiori be extended to the field of national constitutional claims. The Court of Justice’s supervisory role and corresponding interpretation of EU law is crucial to achieve that goal. Such accommodation of constitutional diversity, resolving actual or potential constitutional conflicts, is normatively desirable to ensure the sustainability of the integration.
