Has the European Court of Justice Challenged Member State Sovereignty in Nationality Law?

In March 2010, the Court of Justice of the European Union (CJEU or Court) handed down its judgment in the long awaited case of Rottmann. This paper explores some of the implications of this important judgment through a series of comments placed contemporaneously on the EUDO Citizenship website and a conclusion finally revised by Jo Shaw in November 2011. The judgment clarifies the relationship between EU citizenship and national citizenship, stating that a withdrawal of national citizenship which results in a person ceasing to be an EU citizen altogether ‘by reason of its nature and consequences’ falls within the scope of EU law and is thus subject to review by national courts and the Court of Justice in the light of the requirements of EU law. The conclusion as to whether national authorities have overstepped the mark will be made in the light of a proportionality test. While Rottmann itself represents an interesting jumping off point for further reflection on the EU/national citizenship nexus, its broader interest partly lies in the fact that it sits – with the benefit of some hindsight – at the beginning of a new period of judicial activism on the part of the Court of Justice in relation to the scope and character of EU citizenship. This broader context is surveyed by Shaw in the concluding thoughts.