Duty to Negotiate Solutions
From the legal doctrine on succession, we learn that there is a general obligation to seek negotiated solutions. Consider, for example, Article 19 of the European Convention on Nationality from 1997 (ECN) that substantially repeats the Art. 10(1) of the 1961 Convention on Statelessness. ‘In cases of state succession, state parties concerned shall endeavour to regulate matters relating to nationality by agreement amongst themselves and, where applicable, in their relationship with other States concerned.’ The ‘duty’ of reaching negotiated solutions is a consistent feature of international instruments dealing with state succession. In September 2012 the Union made a formal pledge that all member states will consider ratification.4 The UK, however, has not signed. ‘The ‘duty’ to negotiate is also reinforced at EU level on the side of the predecessor EU member state which must observe the principle of proportionality [and other general principles of EU law] when drafting the new nationality legislation in the event of the independence of part of its territory’ (Gonzalez Marrero 2016, 108).
The obligation to negotiate was also mentioned in the decision of the Supreme Court of Canada Reference re Secession of Quebec. In the advisory Opinion by the Canadian Supreme Court issued at request of the government on the issue of secession of Quebec, the court found that.
the federalist principle, in conjunction with the democratic principle, dictates that the clear repudiation of the existing constitutional order and the clear expression of the desire to pursue secession by the population of a province would give rise to a reciprocal obligation on all parties to the Confederation to negotiate constitutional changes to respond to that desire (...). The corollary (...) is an obligation on all parties to come to the negotiation table.5
There may thus be a constraint on the possibilities of limiting ‘acquired rights’ of UK nationals in EU27. It has been suggested that ‘UK citizens in the EU would have a legal position inferior to Russians and Moroccans (whose countries have non-discrimination agreements with the EU)’ (Kochenov 2016) but the duty to negotiate solutions would not be compatible with such treatment.