The received wisdom on Union Citizenship is statist: it is thought to be intrinsically connected with the State of nationality being a Member State of the European Union, and so no one can be a Union citizen otherwise. The purpose of this article is to challenge this conception. It argues that Union Citizenship institutionalises the idea of individual membership in the EU and its legal order, into which individuals are included and from which they cannot be excluded en masse either by the European Union or the Member States. Citizens are protected against physical exclusion by way of extradition and expulsion and, even more so, against being stripped of Union Citizenship against their will. Union Citizenship, once conferred, cannot be removed without cause in the person of the citizen, even though the rights contained therein may change over time.This is, however, precisely the spectre of Brexit. The effect of this first withdrawal of a Member State on the citizenships of UK and EU-27 nationals remains unclear, and the statist and individualist conceptions of Union Citizenship produce diametrically opposed consequences. The statist conception implies that Brexit extinguishes the Union Citizenship of UK nationals. But the individualist conception of Union Citizenship implies that the citizenships, and the rights contained therein, will survive the end of UK membership in the EU. This ‘Continuity’ Union Citizenship becomes the salient touchstone of this conceptual shift advocated here; EU (and UK) action to preserve it, either through the Withdrawal Agreement or legislation, is declaratory rather than constitutive. If this is correct, little changes as a consequence of Brexit.The principal argument in support of the received statist conception is that the Treaties connect Union Citizenship with EU membership of the State of nationality. But the article argues that the individualistic idea of Union Citizenship has indeed been institutionalised by the Lisbon Treaty, with the analysis proceeding in four steps. First, Union Citizenship is not just a status but a fundamental right. Any interference with it is thus subject to the principle of proportionality and cannot affect its core. Second, deciding on the acquisition and loss of Union Citizenship is not a right but a competence of the Member States. This competence is not unlimited. Third, Union Citizenship is autonomous from the nationality of a Member State. Third-Country nationals may continue to hold the rights of Union Citizenship provided a sufficiently close link exists with the EU. Fourth and finally, the EU is obligated to ensure legal certainty for citizenships beyond the end of a State’s membership in the EU, and the Lisbon Treaty confers the requisite competence in line with the international law of treaties
