Consequences for Member States
The policies listed above would fall within the remit of European law, allowing the European Court of Justice to scrutinise their legitimacy as long as the negotiations would last. The doctrinal limits in European law and their anticipated consequences for member states vis-a-vis UK nationals are also worthy of attention. Member states are hindered from a series of other actions that may tempt or that have already been suggested. In particular, there are limits to what member states can do to both assist and deter British citizens from continuing living in the Union and eventually naturalising there. Member states cannot ‘punish’ British citizens: Some countries having many nationals resident in the UK and that have been particularly targeted in the Brexit debate may not, for instance, render family reunification for British citizens harder, since it would violate the principle of legitimate expectations. Perhaps, it would also be advisable to let British citizens naturalise in Spain without enforcing the ban on dual nationality; or let them naturalise regardless of performance in integration tests in countries requiring these.
Academics have suggested naturalising Brits to save their rights (Kochenov 2016; Steinbeis 2016). Similar ideas have been voiced by senior politicians. Matteo Renzi hinted that British students might be offered naturalisation in Italy. German Vice-Chancellor Sigmar Gabriel said the remaining members should not ‘pull up the drawbridge’ for young Britons, and Germany should consider offering dual nationality to young British citizens.22 Such suggestions may be at odds with EU law. While individual naturalisation cases would fall within the competences of member states, it has become increasingly clear that were a member state to singlehandedly offer such en masse naturalisation it would challenge the principle of sincere cooperation. It is worth recalling that the Commission’s DG Justice proceeded to infringement proceedings against Malta in relation to the Individual investor program initiated in 2013, which had been criticised by the European Parliament. It was the first time that a member state’s nationality law was subjected to substantial amendment following an infringement proceeding. It has been pointed out both in literature (already in Kotalakidis 2000) and in court that the principle of sincere cooperation constitutes a limit to the exercise of state discretion, specifically in relation to what would be a mass naturalisation. If such naturalisation is to be an option, it requires the assent of the remaining 26 States. The Advocate General Poiares Maduro stated that provisions of primary Community legislation and the general principles of community law could restrict the legislative power of member states in the sphere of nationality: ‘Thus, mention has been made (...) of the Community principle of sincere cooperation laid down in Article 10 EC, which could be affected if a member state were to carry out, without consulting the Commission or its partners, an unjustified mass naturalisation of nationals of non-member states.’23
Finally, another possible doctrinal limit of EU law is the requirement to offer time to re-lapse. After Rottman, citizens need to have a chance, before their newly acquired member state nationality may be revoked, to apply for the re-acquisition of their old nationality. Commentators have ventured a reasonable timeframe would be ‘a few years.’ It is questionable if the Court would accept immediately effective deprivation. In the case of exit from the Union, this may be a doctrinal construct relevant to cover cases of second country nationals who naturalised in the exiting State but now wish to recover their original citizenship so as not to lose Union citizenship. Given the traditional tolerance of multiple citizenship in the UK, nonetheless, this is unlikely to constitute an impediment in practice since naturalisers never were requested to renounce their prior status.
There are limits to what States can do, even within their domaine reserve that may prove to have repercussions on domestic legislation insofar as it is not overturned after exit. The limits stemming from European law are therefore significant, even though limited in time. To be sure, the European Court of Justice remains a powerful player throughout the negotiation phase. Perhaps later also were the European Court ofJustice selected as conflict resolution mechanism in the withdrawal treaty. Yet it is far from clear that general principles of European law would be successfully invoked before UK courts. Some have rightly stressed that the introduction of Union citizenship places an important limit on the power of member state to deprive an individual of his or her nationality (Hall 1995, 1996, 2001). However it remains to be seen if limits to State discretion could offset domestic initiatives when at stake is the power of a former member state to deprive its own nationals of their Union citizenship.