Historians, faced with exaggerated claims, tend to reply with the deflating question: so what? What, indeed, is the wider significance of the highly complex Supreme Court judgment on triggering Article 50?
In most ways it was hardly surprising. It reminded us that able lawyers tend to think alike (they are trained to do so), but raised no major new issues. Indeed, the Court acted with restraint in two respects that will have important consequences. It dismissed the claims of the devolved administrations to have a veto over Brexit. And it explicitly said that the briefest Bill would be sufficient, when the Court had no need and arguably no authority to say anything about the extent of the parliamentary action it mandated. But the problems raised by the judgment of the Divisional Court on this question in December 2016 remain.
The three judges of the Divisional Court, and the eleven judges of the Supreme Court, acted with personal integrity and matched the highest standards of professional probity. Public opinion is reported to back them by a wide margin (although, given the low standing of politicians, this may not be a secure foundation for the future). But, as so often, it is our virtues that undo us, not our vices.
The broader historical framework is more revealing than the complex legal arguments rehearsed with such skill by the Court. Since 1973, authority had ebbed away from the Westminster Parliament to the EU Commission, and Parliament pretended that this was not happening. However, it was happening, and it gradually created a power vacuum at the centre. Now two practices or institutions are drawn in to seek to fill that vacuum: the referendum, and the Supreme Court. Will either prevail? Will Parliament reassert itself? Nobody can predict the outcome; but an historical analysis tells us more than a legal one.
How do the technicalities of this case illustrate the wider scenario?
The arguments of counsel on both sides, and of the judges, have this in common: they address the problem that the legislation at issue (notably the European Communities Act 1972 and the European Union Referendum Act 2015) did not contain ‘clear words’ to provide for the situation that arose with the unexpected referendum result of 23 June 2016. The lawyers on both sides therefore argued to a large degree by inference.
But the key question is: if the relevant legislation was so very incomplete, and on so momentous an issue, who or what should now make provision to supply the gap? A referendum, even a second one? Parliament, or a new Parliament after a dissolution? The courts, in this and future cases? An answer is unclear, for at least two reasons.
First, a new animal has arrived in the public arena, the referendum. The judges, and many parliamentarians, wish to ignore it. But that does not disarm it. Second, the Supreme Court is developing an activist understanding of its role, echoing the European Court of Justice rather than the conventions that prevailed in England before the Supreme Court was created. Historians may notice that the judges in the Divisional Court had invented a new sort of statute, which they called a ‘constitutional statute’, which they deemed to be more important than other statutes, and which could be interpreted only by themselves. But their precedents were only other court cases from as recently as 2003 and 2014, not primary legislation. So much, one might say, for the supremacy of Parliament. The Supreme Court also appealed to history; but its history was flawed.
It follows that the Supreme Court judgment does not uphold parliamentary sovereignty, even though it professes to do so. On the contrary, it tells Parliament what to do, and Parliament will now obey. The judgment takes as irrelevant the fact that Parliament could already have chosen to pass a Bill to trigger Article 50 on many occasions since 23 June last year, had it wished, but had not done so. Parliament could also have voted out of office a ministry openly seeking to use prerogative powers to trigger Article 50, but, again, Parliament had not done so.
As in most great constitutional conflicts, a plausible legal case can be made on each side: the dissenting judgments of Lords Reed, Carnwath and Hughes were no less cogent than those of their colleagues. The consequence is that the judgment of the majority unintentionally politicises the Supreme Court. In a conflict polarized between Leavers and Remainers, there was probably no middle course. But the case erodes the idea that the judiciary is politically neutral, just as the high Europhile ideals of that acclaimed public servant Sir Ivan Rogers undermined the idea of an independent, apolitical civil service. Both professional self-images are approximately a century and a half old. Both were, arguably, valuable myths. But they were never eternal truths and never accurate historical guides to how courts and civil servants behaved: judges especially were more often politically controversial than immune from political objection. Civil servants and judges always, and inevitably, took sides.
The current recourse to the Supreme Court therefore reminds us that judges are unelected and unaccountable, and that they wield arbitrary power. It may be that the long-term outcome of the case will be to promote a redefinition of the Supreme Court’s role, and to strengthen the new practice of the referendum rather than to strengthen Parliament. Nobody can predict, since none of us, perhaps fortunately, is an ‘expert’. But it would be ironic if the UK left the EU only to find itself with a Supreme Court that behaved in key ways like the European Court of Justice.
 The Supreme Court judgment, 24 January 2017, paras. 41, 43, 44. This argument will be easily recognized as the ‘Whig interpretation of history’, long discredited among historians but evidently alive and well among lawyers.