If the coronavirus crisis proves to be a tipping point on Scottish independence – and it looks like it could be – then a few things need to happen next.

First, unionists need to be preparing their strategies for another referendum (and, although some work has started in the Tory party on this, not a lot is really being done).

Second, supporters of the Union need to prepare themselves for the possibility of losing – politically, but emotionally too.

And third, all of us in the debate should probably take a look back at how we got here, because the path behind can predict the route ahead. And it may even offer a little hope for unionists.

But it’s not going to be easy, because, in some ways, polls showing 58 per cent for independence, as well as 53% for the SNP in the constituency vote at next year’s elections, seem to defy political and social logic. There were unionists who hoped the virus would “bring the UK together” and historical precedents (most notably, the Second World War) appear to support them.

Instead, exactly the opposite is happening. Wales is telling people from Liverpool to keep out. Scotland is telling people not to go to Blackpool. And now 58% of Scots say they want to get out of the UK altogether. The virus is proving to be anything but unifying.

The polls in Scotland also seem to defy logic in other significant ways. Nicola Sturgeon is in the depths of a crisis that centres on the Salmond inquiry and normally she’d be in serious trouble. And yet, right in the middle of the school exams debacle, a YouGov poll registered SNP support at 57% in the constituency vote.

The same applies to Margaret Ferrier, the nationalist MP who broke the coronavirus rules. In normal circumstances, MPs’ mis-behaviour saps energy and credibility from a party and even Ian Blackford, the SNP’s leader in the Commons, said he was worried Ferrier’s refusal to resign was putting support for independence at risk. He needn’t worry. It isn’t.

Some people would say the support for Sturgeon, and independence, is because of the way the First Minister has handled coronavirus and she’s certainly presented her case better than the PM – but then Sooty and Sweep could handle a press conference better than Boris Johnson. In every other respect however, the First Minister has made broadly the same decisions, and cock-ups, as the UK Government. And yet Sturgeon’s satisfaction rating is in the 70s.

The explanation, or part of it, lies in the Ipsos MORI poll that shows support for independence at 58%. It found that only one in four Scots see the long-term economic argument for independence as very convincing, which suggests many of those who don’t find the economic case convincing still support independence. Why?

The answer lies in something you could call “oppositional support”, which is the phenomenon that in some cases, people’s views tend to be formed by what and who they oppose rather than what they support, and it seems to be particularly the case in Scotland.

The Ipsos MORI poll backs it up. Most Scots are unconvinced or have their doubts about the economic case for independence but the same poll shows that 63% are convinced by the argument that “Scotland should be independent because Westminster governments cannot be trusted to act in Scotland’s interests”.

What this seems to demonstrate is that the views of many Scots on independence aren’t being influenced by what they believe on the economy, but by their lack of trust in Westminster – and more particularly, Tory Westminster. What they support (independence) is being influenced by who they oppose (Tory prime ministers).

The SNP know all of this, and they know the UK leadership is a factor they could use in any referendum such is the strength of feeling among Scots. But the fact that you don’t like the current PM is not a sound basis for fundamental constitutional change and the same applies the other way around. The Scottish minister Humza Yousaf said you cannot divorce the rise in support for independence from Sturgeon’s leadership and he’s probably right. But the constitution goes much deeper than who happens to be FM or PM and whether they are good or bad.

The problem is that our current constitution has the phenomenon of oppositional support hard-wired into it, and it’s been there for ages. It helps explain why Labour dominated Scottish politics for so long: much of their support was based on opposing the Tories and as long as they did that, they won in Scotland pretty much regardless of policy or cock-up or crisis. Now the same thing applies to the SNP.

How do you fix it? Tricky one. First of all, we shouldn’t underestimate that low, low figure of 27% of people who find the economic arguments for independence very convincing. The spin that the pro-independence group Progress Scotland put on their own figures was that 75% of Scots would back independence if they were convinced it would be good for the economy, but ultimately a lot of Scots still don’t buy it and that will be a big factor in any future referendum.

But it doesn’t fix the “oppositional support” problem. A Labour government would help, because most Scots are less opposed to Labour than they are to the Tories, but that remains a relatively distant prospect. Keir Starmer is also in the trap that he cannot reform Scotland’s constitution until he wins in Scotland.

The second option – and perhaps the only realistic one left – is further constitutional reform. You may have seen my interview the other day with the former Labour MP Paul Sweeney. He talked a lot of sense. The voting system needs reforming, he said, but the UK also needs a federal parliament with new processes of co-operation and free of English domestic politics.

I appreciate some unionists think this is retreat disguised as attack and that it fails to learn the lessons of the 90s when we were told devolution would dampen down the case for independence only for it to do the opposite. But continuing with the current system is not an option. It builds in the oppositional support that’s fuelling support for Sturgeon and independence. It also apparently creates a system in which a government party isn’t held to account for its mistakes. That cannot be healthy, and it cannot go on.

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