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.