THIS is getting interesting.

As you know, most of the recent polls have shown the SNP slipping back a bit, but then we got The Herald poll at the weekend which had the party on course for a majority again.

No one knows exactly what’s going to happen in the end, but the fact that it’s so close, and up and down by only a percentage point or two, is revealing. The SNP is edging along a faultline – or rather several faultlines – that have always existed in Scottish politics and probably always will. It may decide the result.

But first, a few observations about the polls themselves. First of all, if The Herald poll does accurately reflect a slight rise in support for the SNP in recent days, we should be cautious about translating it into seats because of the weird election we’ve had.

An unprecedented number of people have registered for a postal vote, for obvious reasons, and most of those will have voted a week or two back on the basis of how they were feeling then, not now. In other words, if there has been a recovery for the SNP in recent days, it may be too late to make a big enough difference.

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The fact that the ups and downs in the polls have been relatively small is also interesting. The SNP is roughly where it was last time, as are the Tories and Labour, with only the Greens showing a more than small change in support. Why might that be? Alex Salmond has been banging on about a super-majority formed by all the independence parties combined and, while polling for Alba is weak, perhaps some of Alba’s message that SNP voters should use their second vote tactically has cut through, except that the voters are going to back the Greens rather than Alba.

As for the state of the other parties, the fact there hasn’t been much change may be because of the weird non-election campaign we’ve had. Not only has campaigning been restricted, no single party or leader has been able to build any kind of momentum. Nicola Sturgeon has been below par, a little wan, a little weary, and Douglas Ross hasn’t been able to find a scab to pick at in the way Ruth Davidson did. Anas Sarwar, meanwhile, is in the strange position of improving his ratings and being likeable without being able to translate any of it into significantly more votes.

What this relative immobility seems to show is that the electorate has hardened around several cores: 45% or so for the SNP, 23% or so for the Tories, and the same for Labour. It also means the result is likely to come down to the marginal constituencies where small changes in support can actually make a difference. What’s also interesting is why the cores aren’t shifting more, why there is a relatively small but soft middle that’s moving about, and why the SNP can’t get the decisive breakaway they need.

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The first thing to say is it really shouldn’t be this way. We know that the young are much more likely to support Yes so, on the face of it, you’d expect that Yes support would have increased significantly since 2014 as – to be brutally frank – older people have died off (at the rate of about 58,000 a year). That’s a lot of voters who aren’t around anymore to vote No, but the fact it hasn’t changed the political landscape very much could be down to the fact that there are divisions in Scotland that are more profound than the division between the young and the old.

What I mean by that is the division, for example, between the comfortable and the less well-off, the division between people who care about the constitution and those who are less bothered, the division between “middle Scotland” and the edges, and possibly the difference too between men and women. You can see all of these factors in how people vote and how they say they will vote in a second referendum on independence and the most important of them is probably the first one: economic.

Take the story about the Royal Bank of Scotland for example. The chief executive says the bank’s balance sheet would be too large for an independent Scottish economy and they’d move their registered HQ to London. Look as well at the comments of Sir Tom Hunter. Sir Tom says the loss of funding from Westminster would harm Scotland’s efforts to recover from the pandemic. And take Nicola Sturgeon’s remarks about the Northern Ireland protocol. She appeared to suggest that there are “easements there” that offer “some template” for how an English/Scotland border could work.

What does middle Scotland think about that? What do people with jobs, pensions, savings, and mortgages say to it all? They say: yikes. They say: we’re worried about what might happen to the jobs, pensions, savings, and mortgages if Scotland went independent, and we’re worried that there is apparently no economic modelling on how independence might work. If they run a business, or work for a business, Sturgeon’s Brexit-style chat about the Northern Ireland protocol and the “potential” of the EU market is also pretty alarming. Middle Scotland wrings its hands and frets.

What makes it even more complicated is that the voters who worry about the economy come to different conclusions: some vote Tory, some Labour, some Lib-Dem, a small number may even flirt with Yes before getting another scare and going back to No. If the economy is the decisive factor, it may also explain the propensity of young people to favour independence: the young generally have less money, therefore less to lose. And the difference between men and women is relevant here too: it’s often women who run household budgets, and women are more likely to be in lower-paid and part-time jobs. In other words, the real determining factor here is the division between people who think they might have something to lose from independence and those who think they might have something to gain.

In the end, it’s this division, this faultline, that I think runs under everything and explains the immoveable core votes and why the SNP haven’t achieved the breakaway they need. The only obvious way for them to do it now, or in the future, is to assuage Middle Scotland’s fears and convince them there’s nothing to worry about, that there is a plan. Perhaps the SNP will do it at some point, in a way they failed to in 2014. But if they do want to hold a referendum in the next parliament, then they’d better get a move on.

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