Article 20(1) TFEU, reflecting Article 9 TEU, establishes that '[e]very person holding the nationality of a Member State shall be a citizen of the Union'. 1 Union citizenship is therefore a conferred status, in the sense that it cannot be acquired through a direct citizen-to-Union process: to hold the status of Union citizen, a person must either be or become a national of one of the Member States.Because of that constitutive link, the Court of Justice has established a role for EU law in reviewing Member State processes for acquiring and withdrawing nationality. While 'it is for each Member State…to lay down the conditions for the acquisition and loss of nationality', they must have 'due regard' to EU law when they do so. 2 In Rottmann, Tjebbes, and Wiener Landesregierung, national authorities took decisions in individual cases, under national law, that resulted in either the prospect of losing or the loss already of Member State nationality and therefore also of Union citizenship. The Court found that where a Member State national is 'faced with losing the status conferred by Article 20 TFEU and the rights attaching thereto', their situation 'falls, by reason of its nature and its consequences, within the ambit of EU law'. 3 It recalled 'the importance which primary law attaches to the status of citizen of the Union' to require that 'when examining a decision withdrawing naturalisation it is necessary…to take into account the consequences that the decision entails for the person concerned and, if relevant, for the members of his family with regard to the loss of the rights enjoyed by every citizen of the Union'. 4 It emphasised, in particular, taking proportionate decisions in these circumstances, 5 which also entails compliance with the Charter of Fundamental Rights. 6 Is there any obligation to conduct a similar assessment of individual situations amid the collective loss of Member State nationality produced by a State's withdrawal from the Union? After all, in Wightman, the Court acknowledged that 'any withdrawal of a Member State from the European Union is liable to have a considerable impact on the rights of all Union citizens, including, inter alia, 1 Article 20(1) TFEU -again, similarly to Article 9 TEU -also states (since the Amsterdam Treaty) that Union citizenship is an 'additional' status that does 'not replace national citizenship'.