If, dear readers, you have any doubts that the parliamentary politics of Brexit have emerged from the fever dream of some demented game theorist, I would just ask you to take a very quick look at the events of last week. In their second meaningful vote on Theresa May’s Brexit deal, British MPs voted it down by 391 votes to 242, a majority of 149. This was an improvement of sorts on the first meaningful vote, which May lost by a majority of 230. MPs also voted to reject a no-deal Brexit and to instruct the government to ask the other EU states for an extension to the Article 50 withdrawal period. At the same time, by a majority of only 2 votes they defeated the Benn amendment, which would have allowed Parliament to express its preferences as to the outcome of the Brexit process in a series of indicative votes, and thus overcome the current impasse.
This week Theresa May seems poised to take her deal to the Commons for a third meaningful vote, most likely on Tuesday or Wednesday, before the EU Council meets on Thursday. She has worked furiously over the past few days to lobby the Northern Irish DUP and the hard-core Brexiteers within her party to vote for her deal, or risk either a very long extension to Article 50 or the UK remaining in the EU after all. This fear is of course the main incentive to bring the various pro-Brexit factions within Parliament and the Tory party to support May’s deal, and it is growing in power as the Article 50 deadline approaches. But because some of these factions have effectively painted themselves into a corner over the supposed downsides of May’s deal, they need something more than fear itself to justify a change of mind to their electorate. They need, well, a fundamental change of circumstances, like re-revised legal advice from the UK Attorney-General, Geoffrey Cox QC. And they may well eventually find that in the customary rule on fundamental change of circumstances, rebus sic stantibus, codified in Article 62 of the Vienna Convention on the Law of Treaties.
Now, if even after two full years into this whole MCFoHP someone told me that Brexit could ultimately depend on Art. 62 VCLT, I would have been perplexed, to put it politely. This is, for all its Roman pedigree, a rule that has never successfully been applied in real life, I would have said. Its requirements are almost impossibly strict. How could something as important as Brexit depend on an international law doctrine of such relative obscurity that even international law textbooks standing at more than a thousand pages devote it less than two? To paraphrase the late Ian Brownlie’s pithy assessment of jus cogens, the rule on fundamental change of circumstance is a car that has never left the garage.
But – but – over the past week the garage doors have creaked open, with a whiff of something tart and pungent. The stillness of things has become disturbed.
Recall that the Attorney-General’s initial advice made no mention of Art. 62 VCLT. His revised advice, which was as I reported debated in Parliament last week, had one oblique reference to it in its final paragraph (para. 19): ‘the legal risk remains unchanged that if through no such demonstrable failure of either party, but simply because of intractable differences, that situation [of a prolonged application of the backstop] does arise, the United Kingdom would have, at least while the fundamental circumstances remained the same [emphasis mine], no internationally lawful means of exiting the Protocol’s arrangements, save by agreement.’
During the debate in Parliament the possibility of termination on grounds of fundamental change of circumstances was then raised in several exchanges (the full Hansard report is here). The Attorney first raised it – unprompted – when answering a question by Sir William Cash:
In the last line of my advice, I say there can be no lawful exit unless there is a fundamental change of circumstance. It is extremely important to remember that there is always a right to terminate a treaty unilaterally if circumstances fundamentally change. There is no question but that we have a right to exit if those circumstances apply.
He then repeatedly referred to the rule when answering the questions of Owen Paterson, Kate Hoey, Desmond Swayne, Helen Goodman, Chuka Umunna, and John Baron. But perhaps the most illuminating was the Attorney’s exchange with the arch-Brexiteer Jacob Rees-Mogg (‘the honourable member for the early 20th century‘), which I will quote in full:
JRM: My right hon. and learned Friend has pointed out that much of what is being said is political as well as legal. Will he therefore set out for the House what penalties might fall upon this country if a future Parliament, which obviously cannot be bound, were to decide to resile from the commitments under the backstop?
THE ATTORNEY: Well, my hon. Friend will know that as an Attorney General I simply could not give countenance to the idea that this country would break its international legal obligations. As I have pointed out to the House, there is a right for the United Kingdom to terminate this agreement. If fundamental circumstances change, in the view of the United Kingdom, it would attempt to resolve the matter within the joint committee and it would attempt to resolve it politically, but if, ultimately, with the sovereign right of this House and of the British Government at the time, the United Kingdom took the view that those fundamental circumstances had indeed changed, it would have an undoubted legal right to withdrawal from any treaty.
Let us be clear about these kinds of absolute interpretations of black-letter text. A sovereign state has the right to withdraw if a treaty is no longer compatible with its fundamental interests or, to put it a different way, if fundamental circumstances have changed. I would say that apart from that, of course this country could resile from its commitments, but it would be unwise and it would not be in the tradition of this country to do so. In those circumstances, it is perfectly true that the only remedies the Union would have would be to take countermeasures, and no doubt it would pollute the atmosphere for fruitful relationships between us, which is precisely why this country will never do it, and neither would the European Union.
Alternatively, if agreement were not forthcoming, it could be respectably argued, if the facts clearly warranted it, that there had been an unforeseen and fundamental change of circumstances affecting the essential basis of the treaty on which the United Kingdom’s consent had been given. Those facts might, for example, be that the prolonged operation of the Backstop was having a socially destabilising effect in Northern Ireland, contrary to its objectives.Article 62 of the Vienna Convention on the Law of Treaties, which is reflective of the customary international law rule rebus sic stantibus, permits the termination of a treaty in such circumstances. It is in my view clear and undoubted in those exceptional circumstances that international law provided the United Kingdom with the right to terminate the Withdrawal Agreement.
Readers may also be interested in the second opinion by David Anderson QC, Jason Coppel QC and Sean Aughey, now also joined Sam Wordsworth QC, deconstructing the FCC argument piece by piece. The Telegraph piece excerpting the Attorney’s new advice also links to the opinion of the Tory Brexiteer ‘Star Chamber’ legal team, which also rejects reliance on FCC.