On June 23^rd the UK referendum on membership in the European Union delivered a clear, if narrow, result: the country should leave. Much still remains open, but as far as that issue is concerned, the matter is decided. I’m sure that British voters had no view about which mechanism would transfer their decision into law; but they understood that something would. No one supposed that a clear result might be treated as a helpful hint to politicians, or as a preliminary comment in a national seminar on the constitution.

Today’s judgment in the High Court repudiates that understanding. (R (Miller) v Secretary of State for Exiting the European Union). Lord Thomas of Cymgiedd CJ, Sir Terence Etherton MR, and Lord Sales decided that the UK executive lacks any power to transmit the will of the people into law by triggering the notification procedure for exit that is outlined in the EU Treaty. The court holds that the absolute sovereignty of Parliament must be respected, and that such prerogative power as the executive has to act in international affairs, including  treaties, can never repeal rights in domestic law. So Parliament must still decide whether to leave the EU. The matter remains open.

The breadth of the doctrine is breathtaking. The court does not merely say that Parliament is not, in this case, strictly bound by the referendum result; it declares that any popular vote is of zero legal relevance until Parliament expressly chooses otherwise. It is not even legally persuasive: ‘a referendum on any topic can only be advisory for the lawmakers in Parliament unless very clear language to the contrary is used in the referendum legislation in question.’ [emphasis added]

If the Supreme Court confirms this decision, the entire national debate on the EU can begin over: in the House of Commons, in the (unelected) House of Lords, then possibly back again to the courts, or maybe even the electorate. And that is what the claimants want: delay and time for second thoughts and further lobbying–not on the ground that the referendum result was unclear or the procedure unfair, but on the ground that the question was wrongly decided.

I agree that the question was wrongly decided. I also think that referendums are a very poor instrument of ordinary governance. But when what is at stake is the boundary of a constitutional people, we have no better procedure than a referendum, and courts should use their powers to uphold, rather than undermine, the result. Those who regret the result (as I do) should spend less time trying to overturn or forestall it, and more time trying to rally opinion around one of the better options that it has left open. Lawyers shouldn’t feel sidelined: whatever happens there will be work for them.

Democracy is government by the people. But the definition of ‘the people’ is not a matter solely for Parliament. It is matter prior to parliamentary democracy, and the legitimacy of Parliament depends on settling it correctly. The people have a right to decide for themselves the most basic terms of their constitution, including the people who will empowered by that constitution. That is why it is for Scots to decide whether to remain in the UK—and not for the UK as a whole; and why it is for the British to decide whether to remain in the EU—and not for the other member states.

What we might call English Constitutional Theory has long distrusted popular sovereignty.  An influential line of thought running from Hobbes, through Blackstone and Bentham, to Dicey and Jennings, equates popular sovereignty with Parliamentary sovereignty. Even today, the High Court repeats with approval Dicey’s words : ‘The judges know nothing about any will of the people except in so far as that will is expressed by an Act of Parliament’. Of course, it is plausible to think that the ‘will of the people’ needs practical expression. But when we have—as Dicey did not—lawfully organized and fair referendum procedures, it is implausible that only an Act of Parliament can ever speak for the people.

The UK has a fluid, informal constitution, and when disputes about its basic ground rules reach our courts, they generally lie in a penumbral zone where, whatever judges pretend, their decisions not only have political consequences but are made, and can only be properly made, on grounds of political morality. There are no ‘purely legal’ decisions at this level.

Today’s decision sidelines an important principle of political morality. It is not inexorably driven to do so by law or by logic. The judgment depends on two propositions that remain as debatable after the decision as they were before: (1) that the UK’s notification to withdraw from the EU cannot be made conditional on anything, and (2) that the European Communities Act 1972 not only gives EU law direct effect in UK courts, but also makes it part of UK law. Since the parties all accepted (1), the court did not test it. On (2), the court rejected the government’s argument that rights of British citizens under EU law result from an interaction of domestic and European law, and do not rest in domestic law alone.  Legal philosophers have struggled with the general issue at stake in (2).  Compare:  if conflict-of-laws rules sometimes require English courts to give effect to French law, does that make French law part of domestic English law?  It is a delicate question.  The Court makes short shrift of it.  Oddly, given its enthusiasm for Dicey’s doctrine that Parliament is omnicompetent, and its insistence that it only addresses ‘purely legal’ questions, the court  declares  (2) wrong because it is unrealistic: ‘In a highly formalistic sense this may be accurate. But in our view it is a submission which is divorced from reality.’

I wish the court’s desire to shape the law with an eye to reality had gripped it in some more helpful way. Since the UK is a union of peoples, not just one people, the declaration that any referendum, on any matter at all, can only ever be advisory will not go down well in Scotland, or in Northern Ireland. Nor will the conclusion, which follows inexorably, that Westminster can by explicit legislation repeal the Scotland Act 2016, notwithstanding what ‘a decision of the people of Scotland voting in a referendum’ (s 63 A) might have to say about the matter.  Does the Act itself give such a referendum legal force?  If so, it only takes a simple majority, which might consist only of English MPs, to amend or repeal it.

Contrast the more sensitive, and sensible, approach of the Supreme Court of Canada when addressing the constitutional significance of a possible referendum result in favour of Québec independence:

‘The continued existence and operation of the Canadian constitutional order cannot remain indifferent to the clear expression of a clear majority of Quebecers that they no longer wish to remain in Canada.  This would amount to the assertion that other constitutionally recognized principles necessarily trump the clearly expressed democratic will of the people of Quebec.’ (Reference re Secession of Quebec, [1998] 2 S.C.R. 217)

The formulation is inexact, but the idea is sound. The idea that ‘other constitutionally recognized principles’ necessarily trump any clear expression of popular sovereignty is a danger to the continued existence and operation of any constitutional order. The Canadian Court knew that to endorse that idea could risk national calamity. By their judgment they changed, if only marginally, the basic ground rules of the Canadian legal system. It was a wise move.  Perhaps our Supreme Court will follow it?

Popular sovereignty is a moral ideal. Parliamentary sovereignty is an institutional device, helpful where it secures important values, but a hindrance when it does not.