IT is a truth universally acknowledged – at least by its advocates – that all things inexorably advance the cause of independence. 

Every development at Holyrood, Westminster, Brussels or wherever must observe this natural law.

Everything either illustrates the logic and appeal of independence or reveals the folly and misery of the Union. 

Every statement and deed by Boris Johnson puts more numbers in the Yes tally, according to the SNP. As does everything else, come to think of it.

In SNP press release after press release, in speech after SNP speech, we are told there is only one direction of travel – onwards and upwards.  

READ MORE: New poll published on Scottish independence 

Come good times or bad, boom times or busts, rain or shine, nothing can ever be admitted to arrest the cause of independence, far less set it back. There is only forward motion.

Which brings us to the coronavirus.

Talented though the media mavens of SNP HQ may be, it is hard to put a positive spin on a traumatic pandemic. 

Most inconveniently, there are some things which are not in the business of boosting the Yes vote after all.

But what difference will it make?

We are still only in the foothills of the outbreak, and the global economy has already been knocked sideways and life for millions disrupted. 

Far, far worse lies ahead.

So it might seem indelicate to bring politics into the equation. But in truth politics never leaves the equation. It is a constant choice about how we live.

READ MORE: New indyref poll - Fewer than three out of 10 want another vote before 2021 

In our small corner of the world, the virus’s impact on independence is already under discussion. One fellow scribbler this week suggested it would do the cause “no favours”.

SNP MPs duly pushed back on the idea that a pan-UK response with a whiff of the Blitz spirit to it would undermine the case for going it alone.

Some, no doubt, will also be pondering how the virus might reconfigure the electorate given the most vulnerable voters are also those most opposed to independence.

But I believe most of our politicians, both at Holyrood and Westminster, will simply have the same instinctive concerns about friends, family and society as the rest of us, and do their best to help the country get to the other side of a grim summer. 

That said, I fear the virus will be more than a match for Nicola Sturgeon, Mr Johnson and their respective public services. 

People, in their distress, will look for someone to blame. But as the disease’s rapid spread has blind-sided the planet, I don’t think either leader will be seen as especially culpable.  

However, I do think the independence debate will change in both the short and medium term.

For one thing, Ms Sturgeon can now drop the dim pretence about a second referendum this year. 

Boris Johnson’s refusal after the general election and the lack of relevant powers at Holyrood always meant Indyref2 was a non-starter before the 2021 Holyrood election, and possibly for some time after that.

Yet to maintain a symbolic flicker of hope, and to avoid getting blamed by her own side for dropping the ball, the FM has kept diminishing herself by insisting it is still a live possibility. 

That can now end. The outbreak means Indyref2 this year is logistically and politically impossible.

Besides ruling out a campaign involving hundreds of thousands of voter contacts, the virus has become every government’s Priority One.

The public will not stand for money and manpower being diverted into naked politicking while it rages.

And despite the protestations of SNP MPs against columnists, the independence cause will suffer. 

Not necessarily because it will look like a bad fit for times of crisis. But because it will look like a decidedly second-order issue. 

Ms Sturgeon hasn’t been able to deliver Indyref2 so far, but she has been shrewdly fostering a sense of inevitability about it happening.

She steadily built momentum, and was set to capitalise on it in 2021.

That is about to change. 

The Yes movement is entering a stall. No marches, no campaigning, no way to spin independence as an answer to the great issue of the day.

That loss of hard-won momentum and a slide down a shell-shocked nation’s list of priorities will change the Scottish political landscape.

 However, that does not mean the SNP Government will be greatly disadvantaged at next year’s election.

The Scottish Tories, after all, had been planning to hammer the SNP on their 14-year record in office. 

But the virus throws a spanner in the stats they intended to deploy. 

The usual ammunition – fresh A&E waiting times, treatment guarantees and exam results – won’t be there. 

Instead, there will be a gigantic aberration, a freak lurch in the data arising from a natural disaster. 

Voters may remember the one-off failures like faulty hospitals and half-built ferries, but the Tory line that the SNP’s record has been on a steady downward track will struggle. 

Nor will Jackson Carlaw be able to credibly claim he could have handled the pandemic better. It will dwarf everyone.

The question for a re-elected SNP would then become when is the right time to restart its old conversation? 

When is the right time to say that independence is again the priority?

It may be a long time indeed.