The supreme court’s batting away of Indyref2 leaves Sturgeon more isolated than ever

Compared with its ideologically zealous US counterpart, the UK supreme court is a cautious group of senior judges. They are careful not to throw their institutional weight around. They are particularly reluctant to get embroiled in politically contentious issues, especially since their predecessors were forced to do just that in the prorogation ruling in 2019. Today, however, the judges put caution aside.The court’s unanimous ruling that the law does not allow the nationalist-led Scottish government to initiate a second independence referendum is politically explosive. After all, the Scottish National party itself brought the case, and this emphatic defeat throws down the gauntlet to the party’s leader, Nicola Sturgeon. In a formidably combative press conference, Sturgeon picked the gauntlet up. Where Scotland’s place in the UK is concerned, the game is once more afoot.But there were some surprises. Before Lord Reed began to give the court’s judgment this morning, conventional wisdom said the ruling would be minimalist. The five judges, it was expected on all sides of the argument, would find a way of accepting the case made by UK law officers during the October hearings. Then, the law officers had argued that a ruling on a plan that had not yet gone through the Scottish legislative process would be premature and hypothetical. It would risk turning the highest court in the country into a general legal advice centre. Many assumed that the judges would seize on this to bat the issue away.As Lord Reed gave the judgment, it became clear that the court was made of much tougher stuff. The case was not premature but was properly brought, he announced. The court was thus required to make a substantive ruling. The critical issue was that any independence referendum, even if it described itself as merely advisory, would be about the union, and thus a “reserved matter” that only the UK parliament could allow. Therefore the Scottish government could not go ahead with its plan. There was nimble judicial footwork alongside the clarity, providing something for both sides, showing the judges are politically aware but not politically tainted.The main consequences are in the here and now of Scottish and UK politics. Note nevertheless that the judgment has legal implications too. It has sharpened the jurisdictional lines in the 1998 devolution settlement between the UK government and the devolved authorities. It has opened up a new avenue for law officers in either the UK or the devolved nations to go to court over legislation that may affect them. The court also eased itself of some striking remarks about the more precise legal meaning of terms such as self-determination, which are regularly invoked in the independence debate as though Scotland were a colonial possession.The response in Scotland’s often brutal social media culture was predictably fiery. It felt distinctly like a moment in which feelings might boil over. They may do so in the future. Sturgeon is clearly aware of this danger. Just two hours later, she did not mince her words of frustration while at the same time pushing back against the headstrong and reckless response that is always such a feature of Scotland’s cyber world. “I respect and accept the judgment of the court,” she said. “The route we take must be lawful and democratic for independence.” These were important words.They also go to the heart of the still unresolved issue of the UK’s future. In Scotland, the argument about independence has never gone away since the 55%-45% vote to remain in the UK. That democratic verdict was supposedly a once-in-a-generation decision. The UK government is not alone in continuing to see it that way. But although other parties remain frustrated by the refusal of the SNP to take 2014’s no as an answer, it has become clear that it is not enough to insist that the matter was settled in 2014.The level of SNP support that was unleashed after 2014 ensures the constitutional question remains the defining divide of Scottish political life. It shows little sign of weakening. There are many reasons for this – including a decade of economic hardship, David Cameron’s clumsy response to the first referendum, Scotland’s strong opposition to Brexit, and the indifference of many English Tories. But the real reason why the issue drags on is that Sturgeon has not been able to translate electoral support for the SNP into a convincing tide of majority support for independence.Back in 2015, Sturgeon said there should not be another vote until independence had become “the choice of a clear majority in this country.” That was briefed by the SNP to mean until the opinion polls showed consistent majorities of about 60% for separation. But such polling levels were never reached. Then came Brexit, which the SNP argued was such a substantial material change in Scotland’s circumstances that it justified revisiting the 2014 decision. That approach faltered too, after Britain finally left the EU.Under increasing internal pressure to call a second vote, Sturgeon has now come up with yet another strategy, offering either a Scottish government referendum on independence – which the supreme court has now blocked – or a general election vote, which Sturgeon dubs a de facto referendum. This is the option on which, in the absence of any other legal route, the SNP has now had to fall back. Sturgeon’s response to the supreme court decision was the starting pistol for that campaign. In theory, she ought to be pleased. It’s the election she asked for.But there are many problems with it. The main one is that an election is not a referendum. It’s a wide-ranging exercise in choosing a government. People cast their votes for many reasons, not for one reason alone frozen in space and time. Parties compete against one another, so although there are other pro-independence parties, the SNP cannot treat their votes as if they were for the SNP. And even if the SNP can claim a majority, its opponents are under no democratic or legal obligation to defer, since this surrogate referendum will not be a contest they recognise.The supreme court, though, poses a real challenge to the pro-UK parties too. Its ruling confirms that a UK devolved nation wanting to secede must first persuade the UK government to concede a referendum on the issue. The pro-UK parties need to make clearer how this can be done. Last year, Michael Gove said that a referendum would be held if there is “a clearly settled will”. What exactly does that mean? Other Conservatives, and the opposition parties, have been more coy.All the current problems stem from the fact – unlike in the case of an Irish unification referendum – that there is no agreed constitutional framework. Instead, it is left to the party that wants secession to make up its own rules, just as the SNP is now attempting to do. Martin Kettle is a Guardian columnist