It’s easy to see why, once you’ve convinced yourself that Scottish independence is a good idea, it should become your over-riding priority. It provides the answer to any other political question that might present itself or, at any rate, a good excuse for not having an answer.

It can be declared that any successful or popular policies show how capable Scotland is, and things would doubtless be even better if we were independent. Any that have been a failure could have been a success, had they not been prohibited or inadequately funded by Westminster.

Taking such positions is second nature for convinced nationalists, but the circularity of the stance is not always the winning objection unionists often imagine. The fact that they can’t be gainsaid isn’t itself an argument against independence, but only against those particular assertions. Since no one can predict the future, perhaps it would solve all problems, in the way that some Brexit advocates seemed to think when advocating the Leave vote. Or perhaps, like Brexit, it would prove messier and more difficult in practice than in theory.

The overwhelming practical difficulty – if you’re in favour of independence – is the Scottish electorate. Even armed with guaranteed solutions to, or semi-plausible proposals for, issues such as setting up a currency or sharing one, trade policy, disentangling pensions, welfare, public infrastructure and assets, the armed forces, sorting out our higher public spending and how it gets paid for, whether we’d be allowed to join the EU, when, and on what terms, and all those other piddling details, people still need to vote Yes, as they disappointingly failed to do last time. By quite a big margin.

That figure will no doubt have changed, but there’s considerable doubt about how much. Earlier this year there seemed to be a pro-indy majority, but such a slight one that it would be a coin-flip, and the last half-a-dozen polls all show a lead for sticking with the UK, with the most recent putting the numbers almost exactly back where they were seven years ago.

Naturally, everything can and often does change during a campaign, but this isn’t the sort of ground that I’d be keen to start from to secure independence. Yet the entirety of the SNP conference this weekend was devoted to insisting that a second referendum is just around the corner (which, at the moment, seems to mean 2023, with the campaign to begin in earnest next spring).

The whole thing is a fiction, since Holyrood has no power to call a referendum and the UK government has absolutely nothing to gain from doing so – unless, of course, it could guarantee that it would be lost. But that would be a brave move, even for even Boris Johnson at his most reckless.

Since the raison d’être of the SNP is to secure independence, I can see why the members are keen to push for it. I can also see why the leadership has to pretend that a vote on the matter will be forthcoming at some point, especially given its claim that the result of the last Holyrood election is a mandate for a rerun of 2014.

Though that’s a pretty contentious assertion at the best of times. Plenty of people vote SNP, or approve of Nicola Sturgeon as First Minister, without necessarily wanting independence. But if that weren’t the case, even, in fact, if you sincerely believe the not-at-all hyperbolic conference claim by Keith Brown, depute party leader and Justice Secretary, that “the future of the planet” requires Scottish independence, why on earth would now, or soon, be the time?

If, as a poll last week found, 68 per cent of the electorate don’t want a referendum in the next 12 months and more than 40 per cent don’t want one at any point in the next five years, it doesn’t seem like a fruitful moment to make the case. I’m not dismissing the possibility that such a vote could be won, even if it were held tomorrow (though I doubt it). I’m certainly not arguing that things (such as, for example, the Westminster government becoming very unpopular) might not change in the near future, and make the circumstances for a Yes vote more propitious.

Indeed, a change in popularity is inevitable in the long run for any government outside North Korea, though it might not automatically help the independence case, since – as the SNP has itself been in government for a long time – it might coincide with a waning in their own popularity.

But if you want to win any vote, you pick your moment if you can. For anyone who actually wants independence, this isn’t a very good one. The difficulty is that this seems to be a concept that very few people in that camp can grasp. It seems to resemble the delusion of Jeremy Corbyn’s more fanatical supporters that everyone in Britain was desperate to vote for him at the last election, and only some conspiracy of centrist Labour MPs prevented it from happening.

The people I suspect do understand the danger of pushing for a vote and losing it are the leaders of the SNP. Ms Sturgeon, as even those who loathe her ought to acknowledge, is possessed of a highly developed political sense; she cannot, right at this moment, be especially confident that she would win a referendum, no matter how much she hopes to and even (much more doubtful) if she thinks she probably would.

But, as we can see from the past few days’ speculation about her future, she must be thinking about what she will have achieved when she finally leaves office – even if she insists that day is still far off. If it’s not independence, by definition, that’s failure for an SNP leader. So she has to pretend she wants a vote now, when she’s not going to get one and, as things stand, would probably lose it, in the hope of a day when she can get one, and might win it.

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