On 23rd June 2016 a majority of the British population voted in favour of leaving the European Union. This is a historical event from any perspective. Never before did a Member State leave the Union. Although there was never a fixed end point for European integration, there was at least the tacit agreement that the project was one-way traffic. That premise has now been turned upside down, leaving millions in the UK and in the European Union shocked and speechless.
Article 50 TEU, which governs withdrawal from the Union, was introduced in the Treaty of Lisbon (2009), mostly as a symbolic gesture. It was designed not to be used. This may also clarify some of the lacunas in the article. There are many different opinions on what the procedure should look like, but legally speaking not much is certain. Whatever is to happen in the upcoming months, the process will be first and foremost political. Law follows politics, and politics follow events. Afterwards, law picks up the pieces. EU lawyers will have to explain what happened and why, and make sense of the new European constellation.
This is what we know: article 50 TEU is the only way to leave the Union. To trigger it, the UK will have to make its intention known to the European Council. Then a clock starts ticking: the UK has two years to negotiate a deal before EU law ceases to apply to it. The timer can be stopped in two ways: 1) if a withdrawal agreement is reached within these two years agreeing on a different date, or 2) if the European Council unanimously agrees to extend the term. This means that article 50 cannot be taken hostage by the withdrawing Member State to enforce Treaty reforms: the European Council can easily block this. After two years, the UK is no longer an EU Member State, and loses its seat at the negotiating table.
The negotiations follow the regular procedure for negotiating agreements with third countries, as laid down in article 218(3) TFEU. The Council appoints a negotiator and decides on a mandate. It approves the agreement by qualified majority. The UK representative in the Council has no vote in this procedure.
Article 50 is silent on some crucial aspects. Firstly: when the intention of withdrawal has to be announced. At the moment of writing, the UK has not yet given formal notice of its intention to leave. It is still a full Member State and EU law obligations continue to apply to it. Some institutions and Member States are putting pressure on the UK to initiate the withdrawal procedure and avoid a prolonged period of uncertainty for member states, markets and citizens. But the UK is not in a rush, preferring to have informal negotiations first. Prime Minister Cameron, who stepped down after the referendum result, has made it clear that this is a task for his successor, but it remains to be seen who in the Brexit camp is up for that job. The sobering compromise came from chancellor Merkel, who said that she will not force the UK into the procedure, but will not have any informal negotiations beforehand either. As in the Eurozone crisis and the migration crisis, her European leadership is being put to the test once again.
A second issue that does not follow from the article, is how the negotiations on a new EU-UK relationship are to take place. Article 50 only concerns withdrawal: it is supposed to ‘take account of’ the seceding state’s future relationship with the EU, but such negotiations could take years or even a decade. Still, secession is closely related to a new settlement, and it is likely that at least some interim measures will have to be negotiated.
Lastly, what would happen if the UK, for whatever reason, decides it wants to remain in the Union during the withdrawal? Here too article 50 is silent, but it is likely that all parties would be willing to stop the procedure. But if the UK does leave and wants to rejoin later, the article is clear: a new accession procedure will have to be started in accordance with article 49 TEU, requiring a new accession treaty to be signed and ratified by all member states.
A lot of uncertainty remains, not just for the UK and British citizens, but also for the peoples of Europe. One of the very founding principles of the European project, its irreversibility, is no longer self-evident. The British vote may have awakened Eurosceptic forces the magnitude of which is difficult to foresee.