I’m not sure it was wise for Nicola Sturgeon to invoke Nelson Mandela in her speech on the next steps (sic) to independence. He was a revolutionary who pursued a campaign of non-violent direct action, including strikes, boycotts and other acts of civil disobedience. That’s what many ardent Yessers were hoping against hope she might authorise.

But it ain’t gonna happen. For this SNP leader, independence is a long game, and a constitutional one. Attention now turns to winning the 2021 Scottish parliamentary election after which Westminster, according to Ms Sturgeon, will have no choice but to offer a repeat referendum on Scottish independence.

But will it? Why would Boris Johnson be any more willing to entertain the break-up of the UK in May 2021 than he is in February 2020? What would be different?

Nicola Sturgeon says it is all about the mandate. She expects to win a majority, in association with the Scottish Greens, and to use that as a signal to Westminster that Scotland demands a referendum now.

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She may be counting her chickens. Not everyone in the independence movement is so certain the SNP will dominate 2021 as it did in 2019. After all, Brexit will be a fait accompli by then.

Next year's election ought to focus on domestic policy, on schools and hospitals, and the SNP government’s record here has been patchy. The nationalists will have been in office for 14 years, and even though the opposition parties, Labour especially, are in disarray, voter fatigue is bound to happen eventually.

But even assuming the SNP do achieve their goal and make another request for a Section 30 Order, what guarantee is there that Westminster will respond? Attitudes have hardened against independence, and not just in No.10. The Labour leadership contenders have made no secret of their hostility to “divisive nationalism”. It has been a recurring theme of the campaign.

Anyway, the opposition parties will not have a fraction of the influence in this parliament that they had in the last, or even in the one before that. For the first time in 30 years, the Conservatives have a united party, a strong leader and an unassailable parliamentary majority. He could be in power for a decade.

Come 2021, he'll say the same as he's saying now: you said it would be once in a generation ... stop trying to break up Britain ... get on with the day job.

A generation can be a long time. According to the Oxford dictionary it is around 30 years, or the length of time it takes for people born on the same year to grow up and have children of their own.

Opinions may differ, but it will be hard to argue that seven years constitutes a generation. And that won’t be the only argument deployed against Indyref '21.

Anyone who thinks Brexit will be done and dusted by May next year is living in a fool's paradise. A bare-bones deal may well be struck by the December 2020 deadline, covering free trade in goods, but huge questions of regulatory alignment will be outstanding.

Nicola Sturgeon says confidently that the “Toaries” will surely make a mess of Brexit and that that will be clear very soon as the impact of hard Brexit bites. But forecasts of doom have not had a good track record.

Remainers in general have relied far too much on project fear. Planes falling out of the sky, food disappearing from the shelves, essential medicines not getting through. None of this has happened or is likely to happen.

There is too much at stake for the EU and Britain not to come to a basic deal to keep things moving. The long-term economic effects of Brexit will undoubtedly be pretty dire. The Treasury forecast is that the UK will lose over 4% of GDP growth, which is as much as in a serious recession.

But we’ve already lost 2% since 2016, according to most estimates, and that hasn’t had much impact on Brexit opinion. Moreover, these forecasts are based on untested assumptions.

Reduced immigration leads to lower growth, but it might also lead to higher wages being paid to workers already in the UK. Wage growth has been ticking up since Brexit.

So we can’t rely on some popular revolt against Brexit, and anyway it’s not clear how a botched Brexit is going to make the case for Scottish independence.

Westminster might just as well say that we’ve had enough of divisive referendums. While the UK economy is under the stresses of transition, now is not the time for a Scottish independence referendum throwing another spanner in the works.

Theresa May said exactly that in 2017, and Boris Johnson, with his huge majority, is almost certain to say the same. Which means there will not be the “legal and legitimate” referendum which the First Minister says is the only one she will entertain.

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She did actually mention in her speech the possibility of a consultative referendum, and said that the time might come when Holyrood’s powers to hold such a referendum might he tested in court. There has been much learned discussion of this on the internet among legally-trained nationalists.

However, she didn’t exactly bubble over with enthusiasm at the prospect. For Ms Sturgeon the only independence worth having is one recognised by Westminster, and the EU, as legitimate. That requires No.10 to agree a Section 30 Order allowing a legal and binding referendum to take place.

She has a point. Unionists might boycott a consultative referendum. Local authorities would have to organise it and voters might regard it as a waste of money since the result doesn’t mean anything. Boris Johnson will certainly say that.

So, it was another dose of sober realism from the FM on Friday. We’ve been here before. It’s not a great prospect for the legions of enthusiastic nationalists who have been led to believe that a referendum is just over the horizon. That horizon is getting more distant by the year.

Some prominent nationalists believe the game’s a bogey. The most influential independence-supporting website, Wings over Scotland, has just thrown in the towel over Nicola Sturgeon’s legalistic approach. The Rev Stu says the site, which has a huge following, and raises six-figure sums each year, will not return until Nicola Sturgeon is history.

That may take a while. There is no obvious replacement for Ms Sturgeon. She's been hugely successful in electoral terms and as this column has pointed out in the past, political parties are mainly concerned with winning and keeping seats. The SNP depends on the flow of cash and energy supplied by its MPs and MSPs. It doesn’t want a repeat of 2017 when the SNP lost a third of its Westminster seats.

The FM is a cautious lawyer, disinclined to lead from the front. Alex Salmond would probably be active in emulating Mandela. Organising campaigns of civil disobedience, withdrawing from Westminster, fighting in the courts, staging “advisory” plebiscites. The kind of “ratchet" approach advocated by The Common Weal activists.

That might or might not work. But the question is irrelevant. The SNP used to regard itself as a revolutionary party not part of the establishment. But it has become the establishment in Scotland. Get used to it.