With the Scottish elections still months away, and the possibility of their being postponed further, one cannot say for certain that there will be a separatist majority in Holyrood later this year.

But despite the fact that the scandal engulfing Nicola Sturgeon seems to be growing more serious by the day, a Nationalist victory – with or without the help of the Greens – remains the most likely outcome for now. Which means that Boris Johnson will eventually come under fresh pressure over granting a second referendum on independence.

Will he? Many people believe so. They argue that the pressure to do so after a separatist victory at a fresh election would be “irresistible”. And in light of unionism’s historical conduct, which has strongly tended towards whatever course of action stops the Nationalists calling them names, however briefly, one can see why they’re confident.

But the Prime Minister apparently insists he won’t, and the logic for that is equally strong. As Scottish commentator Tom Gordon has spelled out, Johnson has no incentive to call a referendum he thinks he will lose. The easiest way to avoid being the Prime Minister who lost the Union is to kick that can onto his successor’s lawn. As for ‘pressure’, it’s meaningless unless you have the means to exert it and the SNP have few means to exert it against a national government with a strong majority.

Yet there is growing recognition that Johnson can’t ‘just’ say no, regardless of whatever George Osborne thinks. A refusal buys time, but it has to be part of a broader strategy which makes use of that time to bolster the Union.

What might that be? According to James Forsyth, writing in yesterday’s Times, the latest proposal is to justify delay by calling a ‘deep’ commission not just into Scotland’s place in the Union, but the entire British constitution. That would allow ministers to explain that Scots should not vote again until they know on what new terms the Union might be available.

On that strictly tactical level, it might work. A substantial share of the devocratic Greek chorus are fixated on the constitution and would certainly enjoy such a circus, especially if it were coupled with the promise of yet more money. It would be panem et circenses, of a very particular kind.

But a Government which has otherwise demonstrated an unusual fidelity to the traditional foundations of the constitution – as evinced by the purist approach adopted to repealing the Fixed-term Parliaments Act – ought to be extremely wary about opening this particular Pandora’s Box. Here are a few of the potential dangers.

1) A field day for the usual suspects

Advocates of every hoary old reform would immediately set to work arguing that the Union could be saved if only the Government adopted their One Weird Trick.

Ministers would be besieged by calls to adopt proportional representation, replace the House of Lords with a ‘Senate of the Nations and Regions’, replace British decision-making with balkanised inter-Home Nations horse trading (mediated by the courts), and even go the whole hog and codify the constitution. And if people like Carwyn Jones get their way, there might even be an attempt to abolish the foundational principle of parliamentary sovereignty itself.

Obviously a majority government can and should reject any and all of these bad ideas, and doubtless there would be an heroic effort by conservative academics and think-tanks to inject some more interesting thinking into that dreary litany.

But Johnson should be wary of miring himself in a series of self-inflicted rows over such topics when he wants to be focusing on building back from the pandemic, levelling up the new areas he won to the Conservative cause in 2019, and generally delivering on issues that ordinary voters actually care about.

2) Old thinking in a new shape

Advocates of a ‘federal Britain’, whatever they mean by that, like to claim that it is fundamentally different to old-fashioned ‘more powers’ devolution because it is about reform of the centre.

But as I’ve argued previously, this can be a distinction without a meaningful difference when it comes to saving the UK. Balkanising British-level decision-making might not give the devolved governments more powers, but it does give them more power to foul the operation of the Union and even more platforms from which to project their grievances.

Unionists need to break out of the one-way, ratchet thinking that casts devolution as a ‘process’ when talking about weakening the centre, but an immutable ‘settlement’ when discussing concessions already made to the devocrats. We have now had devolution in place for 20 years, and it is perfectly reasonable to include a critical reassessment of powers already devolved in any overall constitutional overhaul.

To date, reformers have ducked this fight. Outfits such as the Constitution Reform Group which started out talking about a zero-based approach to the constitution inevitably conclude that the existing powers of the devolved legislatures should remain in place to the last dot on the last i.

Fortunately, this Government seems to be made of sterner stuff. It’s determination to correct some of Theresa May’s mistakes via passing the UK Internal Market Act suggests that ministers have finally broken the Whitehall omertà on restoring the proper powers of the central state. But if any commission is not prepared to do this – and endure the inevitable cries of being an ‘assault on the devolution settlement’ – it will not be fit for purpose and should not be undertaken. It would just be ‘more powers’ in a new shape.

3) A counter-productive distraction

It is an article of faith amongst enthusiasts for constitutional reform that there has to be a ‘solution’ to Scottish separatism, and that the solution lies in their field and can thus be found with sufficient application of their own cleverness to the problem.

Rather than buying into this, the Prime Minister should do the SNP the courtesy of taking them at their word. This battle is not a good-faith dispute about how the United Kingdom is governed. It is at heart a zero-sum battle between people who want the United Kingdom to exist, and people who don’t.

Most voters do not care about the detail of the constitution. Ministers should weigh very carefully the theoretical gains of any reform against the much more concrete danger of the increased opportunities it will give hostile politicians to undermine the Union. The more you make the proper functioning of the UK dependent on the active cooperation of the devocrats, the less likely it is that the UK will work.

And it is ultimately only by making the Union work that the Government can really defend it. In his piece Forsyth sets out some of the new measures ministers are looking at on this front, such as “more drug treatment beds in Dundee or more ferries to the islands”, then writes:

“It’s unclear how much of this, if any, would work. The UK’s procurement of vaccines means Scotland has a greater share of its population covered than any country in continental Europe. But there’s no sign of a Union dividend in the polls yet.

But this misunderstands the scale of the challenge. The UKIM Act is the first step towards rebuilding the proper position of the British national government after two decades of continual erosion via fire-and-forget devolution. If this strategy were going to succeed overnight, it would not be so essential to hold off on granting another referendum.

But a truly effective (‘deep’) cultural and structural strategy will take time to deliver, not to mention huge reserves of energy and imagination. Which is why Johnson should think very carefully before squandering his energies fighting the pointless, defensive battles an ill-judged commission will invite. And if he does choose to set one up, he could have a good idea of what it’s going to say before he does.