Can anybody stop Boris Johnson breaking the law?

The prime minister’s desire to override parts of the Northern Ireland protocol in the UK-EU withdrawal agreement has caused something of a storm. Boris Johnson’s critics question why he did not previously spot any flaws in his “oven-ready deal”; moreover, whatever the problems, to unilaterally try to amend an international treaty would be a breach of international law, with all that implies.

The prospective assault on international law has been confirmed by the Northern Ireland secretary, Brandon Lewis. Mr Lewis told the House of Commons that the move will indeed break international law “in a limited and specific way”. He has claimed precedent in the 2013 Finance Act making provision to deal with tax dodging and vary international agreements unilaterally. That has been denied by George Osborne, the chancellor of the time. People on both sides have offered interpretations of various clauses in the UK-EU withdrawal agreement that might justify the government’s actions. However, some of the arbitration procedures have still to be agreed.

There are, in fact, a number of ways the government’s bid to override the withdrawal agreement can be stopped.

Legally, it would be strange if no one thought to try to refer it, via lower courts in England and in Scotland respectively, to the UK Supreme Court. The controversial judgement by Lady Hale’s court last year on the prorogation of parliament serves as an example of how the Supreme Court stands ready to exercise a constitutional role. Judicial review, then, is a possibility (as is a review of the UK-EU withdrawal agreement, in whole or in part) by the Court of Justice of the European Union. Alternatively, it could, possibly, be referred to the International Court of Justice or some other international arbitration if the parties wished to (though they seem not to want to).  What ministers would no doubt call “activist lawyers” are already preparing their briefs.

Which way would the judges go?

Some indication of this is given by the resignation of the head of the government’s legal department, Sir Jonathan Jones, an obviously distinguished and well-regarded civil servant (and no “activist lawyer”). Plainly, Sir Jonathan was unhappy with the idea of a unilateral conscious violation of an international treaty, and so much so that he sacrificed his career. It has been reported that there were disagreements between the attorney general’s team and the Cabinet Office (responsible for the UK “internal market” legislation that will override the UK-EU withdrawal agreement), and also between the attorney general Suella Braverman and Sir Jonathan. 

There is also some suggestion that Ms Braverman’s predecessor, the fruity-voiced Geoffrey Cox, was, to put it crudely, sacked because he was uncomfortable with the prospective reneging on UK international commitments. So there is some evidence that senior legal figures have their doubts about the government’s attempts to alter the withdrawal agreement.

Constitutionally, there are a few other contentious points. One is whether what the government is doing complies with the Ministerial Code, a quasi-constitutional document that makes the basic demand that ministers obey the law. There is also the question of whether ministers will use the right procedure to formally order civil servants to undertake actions they see as unlawful. A further question is whether the new Internal Market Bill will negate parts of the devolution settlement with Scotland. 

The judges might also adjudicate on whether the Northern Ireland assembly and executive should have a say in this rewriting of “their” protocol in the withdrawal agreement under the principle of democratic consent. The Supreme Court will no doubt also be asked how the Good Friday Agreement, another international treaty that forms part of the UK constitution, affects and is affected by changing the withdrawal agreement.

One irony may be that the tariffs and checks on goods moving either way at a GB-NI border are actually required under World Trade Organisation rules, not just the EU’s. Even under a no-deal WTO Brexit, the checks might be inevitable or would have to be moved to the Ireland-Northern Ireland border. The WTO court, the Appellate Body, might deal with the case, except that the Appellate Body is inquorate and non-operative because Donald Trump won’t nominate new justices. 

Finally, if they’re feeling adventurous the UK Supreme Court judges might offer an opinion on the application of the 1970 Vienna Convention, a treaty about treaties that in essence says countries cannot be bound forever by international agreements they wish to rescind.

All that, though, would only be necessary if political solutions to the impasse failed, and they might not. MPs could, for example, simply refuse to vote for that part of the UK Internal Market Bill that would break international law, and/or amend the relevant clause. With a Commons majority of more than 80 and most of the old guard pro-Europeans purged, it seems unlikely that there’d be enough Tory rebels to inflict a defeat. Mr Johnson could also rely, this time, on the Democratic Unionists, who felt so betrayed when Mr Johnson agreed to the Northern Ireland protocol.

The other way the issue can be resolved politically is for both sides to agree to reopen the withdrawal agreement in the light of the unexpected advent of a no-deal Brexit. Whatever the private thoughts and motives of both sides, it was not the broad deal envisaged in the political declaration agreed with the withdrawal agreement last October. 

It carries little legal force – though both sides are supposed to try to make it work and it does have some moral and political weight. Bringing the withdrawal agreement back into the talks would certainly suit the British, and possibly avoid the no-deal outcome. This would especially be true if items such as the £39bn “divorce settlement” was in play again.

Tactically, it may well suit Mr Johnson to pick a fight with the EU and the judges, just as it did before the general election last December. It means he can pose, fairly or not, as a champion of Britain’s interests, making only modest demands for a free-trade deal but being treated with contempt and deceived (supposedly) by an arrogant EU machine. Brussels would once again be portrayed as acting in concert with the “Remain establishment” in the opposition parties, the media and the law. It would be the “people’s will” versus the elite yet again, another skirmish in the culture wars that pass for British politics. 

Who wins those wars will not, in the end, be decided in the negotiating chamber or the courtroom, or even in parliament but at the ballot box.