ASK yourself this. Who is smiling and who is downcast this weekend in the aftermath of the Supreme Court ruling on a further independence referendum?

The happy band? Tory politicians, several of whom summoned a subdued smile to their countenance as I chatted with them at the Herald Scottish Politician of the Year event.

Indeed, there was even mischievous, random gossip to the effect that there should be a special award for Lord Reed, the Scottish Court President who delivered the decision. Defender of the Union, perhaps?

Now, this was simply ephemeral, pop-up banter. Momentary mirth. To repeat, those Tory smiles were partly subdued.

Why? Because the issue of independence is very far from settled. Yes, one avenue has closed. Rather firmly, as it happens. But others may present themselves.

Among the more downcast, I would count those Nationalists who were already sceptical about their leader’s tactics, who had been urging a substantive discourse about strategy.

One said to me that the Nationalist cause has been damaged because the impression may gain ground that independence itself has been rejected, despite Lord Reed’s admirable clarity to the contrary.

Another gloomy SNP interlocutor said that independence was now “years away”.

I believe that Nicola Sturgeon was reflecting that subterranean mood within her own party when she announced plans for a special SNP conference early in the New Year.

She went further, insisting it would be up to the party as a whole to decide the next steps – while adding that the “first and most obvious opportunity” to press the case would be the UK General Election, expected in 2024.

That, she repeated, could be a “de facto” referendum upon independence. But the party would determine tactics.

Did anyone seriously expect a different outcome from the Court? Even the Lord Advocate, presenting the Scottish Government case, stressed she was seeking clarity.

She got it. For Nationalists, Lord Reed was exasperatingly succinct. Powers over the constitution and which impinged upon the sovereignty of the UK Parliament were reserved to Westminster. Exactly as the framers of the 1998 Act intended.

Lord Reed dismissed the suggestion that such a plebiscite could be lawful because it was consultative, rather than binding, and thus not directly related to the continuation of the Union.

It was important, he ruled, to deal with the practical consequences of actions – and also to consider the “ordinary meaning” of the language used. A novel concept for the upper courts, cynics might suggest.

So where now? Ms Sturgeon will presumably pursue her “de facto” referendum, although there was a scintilla of wriggle room in her comments.

By “de facto”, presumably she means that the election would be, in practice, a full test of Scottish opinion anent independence – although not a formal referendum “de jure”, that is in statute.

But would that work? The pro-Union parties are making adamantly clear that they will decline to play, that they will regard the next UK election as being just that – a choice of UK Government via individual constituency contests.

As one senior figure put it to me, leaders do not get to choose the terms of an election. Just ask Theresa May who, in 2017, sought to strengthen her hand in Brexit negotiations with a vapid offer of “strong and stable” governance. She duly lost her majority.

Further, an election is not a referendum, de facto, de jure or anything else. It would not mandate independence.

However. Consider a scenario in which Ms Sturgeon pursues her ambition – and falls short of obtaining half the popular vote, the aim she has set herself. Even combined with support for the Greens and Alba.

Do you believe that, in such circumstances, supporters of the Union would say: that’s OK, doesn’t count, we never saw this as a referendum anyway?

No, they would proclaim that the people had spoken – and, again, rejected independence.

Given that, is it not reasonable to suggest, by contrast, that a clear victory for the SNP would pile further pressure upon the UK, either to negotiate independence or, more feasibly, to hold a legally constituted plebiscite?

Perhaps, indeed. However, some in the Nationalist camp fear that it is risking too much to stake independence on an election where other issues may dominate and where the people may be confused, including those who might otherwise accept the end of the Union.

Which is prompting other ideas to emerge. Some say MSPs should resign, forcing a Holyrood election. But people might see that as a dereliction of duty at a time of crisis – and an unnecessary waste of effort.

Others say the SNP should set aside the referendum and focus on building support for independence in civic Scotland. What is envisaged is a form of independence convention, on the model of the cross-party body which paved the way to devolution.

But independence tends to be somewhat more polarising. Devolved self-government was accepted, in practice, by the SNP even though they absented themselves from the Constitutional Convention.

Perhaps then the scenario returns to basics. To prolonged, persistent campaigning for independence. Speaking to an SNP dinner in Glasgow, Nicola Sturgeon said the Court ruling had “galvanised” the independence movement.

Maybe. But to what immediate end? Entirely understandably, Nicola Sturgeon is unable to be precise about the route ahead, other than to remind her party that independence will only be achieved via “lawful and democratic” means.

Which brings me back to the Conservative response. I thought the Prime Minister was deliberately constrained in his comments.

No triumphalism, whatsoever. Equally, and also deliberately, no answer to SNP demands as to how, precisely, Scotland can make a democratic choice about her future, in the absence of a referendum.

This matters. A former Tory Prime Minister once told me that, contemplating Scotland, they had no intention of becoming a contemporary George III. The sovereign who “lost” America.

Scotland and England agreed to form a Union. Now, half the citizens in one signatory to that treaty want to resile from the deal.

That remains a significant issue for both Prime Minister and First Minister, even though the Supreme Court ruling means that it is not immediately pressing.