Unfortunately, though, this U-turn is going to be disproportionately harmful to the SNP, because by relative historic standards the Tories did particularly well in Scotland in 2017, meaning there are more seats here where the Tories will be getting a free pass from the Brexit Party than there otherwise would be. There's no getting away from it - this is going to make it somewhat harder for the SNP to win back the twelve seats they lost to the Tories two years ago. Not impossible by any means, but a bit harder.
I know some people (OK, Ian Smart) will now glibly add the Brexit Party share of the vote to the Tory share and argue that gives a better indication of the state of play in Tory-held seats. If we do that for the most recent full-scale Scottish YouGov poll, it would put the Tories on 28% of the vote and the SNP on 42% - and that still represents a 3% swing to the SNP, enough to see three Tory seats tumble. But it doesn't work like that anyway, because not all Brexit Party supporters will vote Tory in the absence of a Brexit Party candidate. From YouGov's datasets, it looks like less than half of people planning to vote for the Brexit Party in Scotland actually voted for the Tories in 2017.
If you're looking for other silver linings, here are a few...
* If Farage is true to his word this time, he'll still put up candidates in 46 of the 59 Scottish constituencies, which should make it slightly easier for the SNP to hold a handful of constituencies where the Tories are in a close second place.
* We know that a minority of Brexit Party voters would otherwise be in the SNP column (one such voter left a comment on this blog a couple of weeks ago), so the absence of Brexit Party candidates in a substantial minority of seats could end up slightly boosting the SNP's share of the national popular vote. That's obviously less important than any failure to gain seats, but the popular vote share will certainly be mentioned after the election and will affect perceptions of how strong the SNP's overall mandate is.
* This shouldn't affect the SNP's chances of gaining seats from Labour. Even if the SNP fail to gain a single Tory seat, and even if they lose North-East Fife to the Lib Dems, holding their other 34 seats and gaining the six marginal Labour seats would still be enough to take them to the psychologically-important figure of 40.
* I would guess UKIP might see an opportunity here to take votes that otherwise would have gone to Farage. We'll have to see if they now put up candidates in a few Tory-held seats.
* A de facto Johnson-Farage electoral pact may scare the living daylights out of some Remain voters and convince them that they shouldn't muck around with their vote at this election. If so, that ought to benefit the SNP, who are the strongest Remain party in the vast majority of Scottish constituencies.
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