With Catalan secessionism on the march, as well as debates about Scottish independence and a looming referendum, the question of EU membership for possible new states has become politically charged. By declaring that any state seceding from a member state would not automatically become a European Union member, EU commission president José Manuel Barroso has dealt a serious blow to a key part of the SNP's plans for a "soft" form of Scottish independence.
EU membership is vital to the SNP's plans in several ways. Automatic membership would emphasise the ease of the transition from being part of the UK to being an independent state, ensure continuity for Scotland's economy and the business world and simplify negotiations with the UK government over independence. While an application for EU membership by an independent Scotland ought to be relatively straightforward, it would mean that the new state would have to spend two or three years outside the EU. Those negotiations might be complicated if Scotland were seen as a precedent for other "discontented" regions like Catalonia or Flanders, and perhaps by issues like the Schengen accord.
In international law, Scottish membership of the EU would depend on the question of which state or states are successor to the present UK. There are three answers to that question: that the "rump UK" of England, Wales and Northern Ireland is the successor state, but a newly independent Scotland is not; that both states are; or that neither is.
The last answer is the least likely and least credible – somewhere, there has to be at least one successor. The balance of views among international lawyers supports the view that the rump UK but not an independent Scotland would be a member, but that is by no means universally held and many disagree. On the international law argument, the position is far from clear, and is unlikely to provide the comfort to Scottish voters that the SNP seeks.
Greater help is to be found in a separate line of argument, arising from the nature of EU citizenship. This was established by the Maastricht treaty in 1992, as something belonging to citizens of a member state and emphasising their shared rights to live and work across the whole of the EU. Initially, many viewed it with scepticism, as a largely meaningless add-on.
Thanks partly to extensive academic work, and partly to judgments of the European Court of Justice, it has come to be seen by lawyers as something much more substantial and meaningful, sitting alongside and complementing national citizenship.
Recent decisions by the European Court of Justice – notably Case C-135/08 Rottman and Case C‑34/09 Ruiz Zambrano – have affected thinking about when and how that citizenship can be acquired or lost. In the former case, an Austrian man who moved to Germany to avoid criminal prosecution could not have his German naturalisation cancelled if that would leave him stateless and deprive him of his EU citizenship. In the latter, the Colombian parents of children born in Belgium and so Belgian citizens could not be deprived of rights to remain or work in Belgium, given their status as ascendants of EU citizens. These judgments might be regarded as "judicial avant-gardism", but they are also clearly part of the body of EU law.
All this bears on the Scottish debate because, if Scotland were to cease to be part of the EU and had to apply for membership, that would involve stripping EU citizenship from people who are current EU nationals.
European court judgments make it clear how hard it is to remove that citizenship, so if a member state breaks up it is unclear whether that takes away EU citizenship. This has led to a legal argument running against the "international law" argument, that if an independent Scotland were outside the EU, this would unlawfully deprive Scottish EU citizens of their rights. That argument has been made most clearly by Aidan O'Neill QC.
In an August answer to a question in the European parliament, Barroso sought to rebut the "citizenship" argument, repeating the treaty's language that "EU citizenship is additional to and does not replace national citizenship (that is, the citizenship of an EU member state)", and that "in the hypothetical event of a secession of a part of an EU member state, the solution would have to be found and negotiated within the international legal order".
He reiterated the strongly "statist" approach in his remarks on Wednesday. This overlooks the jurisprudence of the European court and the scholarship surrounding that; Barroso sees the EU in a more conventional way as simply a club of states, which triggers ancillary rights for individuals only as a side-effect, rather than putting them at the core of what the EU is now about, as the court and many scholars have.
Barroso's position looks like a powerful rejection of that line of reasoning, and an assertion of a more conventional realpolitik. While the "citizenship" argument bolsters the SNP's claim to EU membership, that cuts little ice among EU-level politicians. At the very least, the uncertainty this creates about the position of an independent Scotland further complicates the SNP's task in an independence referendum.