What I find curious, though, it that one of the conditions for this 'completely accidental' scenario falling into place is that the "Tories have to win" any election in December. And yet that of course means the SNP would lose the leverage Mr Campbell wants us to believe they have in the current hung parliament and that could supposedly secure a Section 30 order immediately if only they would listen to him. So is having leverage in a hung parliament suddenly now a bad thing? I'm confused.
The reality is that anyone paying attention over the last couple of weeks will have been thoroughly disabused of the notion that Boris Johnson is a man open to cutting painful deals with the SNP. As Ken Clarke has pointed out multiple times, the arithmetic is probably there to pass the withdrawal agreement right now without the SNP, and it probably would even have been there to pass the agreement in time for 31st October. But Johnson didn't actually want that - he pulled the bill rather than submitting a more realistic programme motion. OK, there was a danger the withdrawal agreement might have suffered 'death by amendment', but he didn't even give himself the chance to find out. He's not remotely interested in compromising with opponents to deliver Brexit - he wants to do it breaking them. If the SNP had turned up at his door offering to back the withdrawal agreement in return for a Section 30, he'd have burst out laughing, and then shut the door - firmly.
So this current parliament is not one in which the SNP have the leverage to get a Westminster-approved indyref. To have any chance of gaining that leverage, there will have to be a new parliament, and that means an election at some point. To that extent what the SNP are doing today makes perfect sense. The objection people are raising is that opinion polls currently point to a majority Tory government, meaning that the SNP still wouldn't have leverage in the new parliament. In fact the situation would have worsened, because there wouldn't need to be another election for another five years, during which time a Section 30 would be essentially impossible. Shouldn't the SNP hold off, therefore, until the polling situtaion deteriorates for the Tories?
The snag is that the SNP don't just need the Tories to be defeated - they specifically need a hung parliament in which Labour are the largest single party. A Labour or even Liberal Democrat majority government wouldn't be much more likely to grant a Section 30 than a Tory majority government. The range of election results that would do the trick is incredibly narrow, and the SNP would look a bit daft if they held off, waiting for the pendulum to swing, and it ended up swinging too far in the opposite direction. There's a long history in the UK of political leaders getting cold feet about holding an election, and then finding that the polling position actually deteriorates afterwards rather than improves - James Callaghan in 1978 and Gordon Brown in 2007 spring to mind.
Waiting certainly wouldn't be a risk-free endeavour for the SNP. Opinion polls have suggested for some time that they're on course to essentially take Scottish Labour out of the game completely. If an election is delayed long enough for Labour to recover (which ironically would be the whole point of the delay!), the chance of a strategic breakthrough for the independence movement might have been squandered. The SNP also appear to be on course for gains from the Tories, even if we're less clear about the scale of those gains - so why would we want to give the Scottish Tories a few more months in which they could potentially bounce back?
I know there are some people who will worry about the effect of being seen to "vote with the Tories" to engineer an election. There was a chap in the comments section of this blog the other day who even threatened to throw away his SNP membership card if the party ever walked through the lobbies with the Tories. When I pointed out that they had already done so several times this year (as had Labour and the Lib Dems) he hurriedly shifted the goalposts and said it would only count if the SNP and Tories went into one lobby and Labour went into the other. Which is nuts, if you think about it - that would be a 'reverse Bain' principle that would give Labour a de facto veto on any step the SNP take.
In spite of Andrew Adonis' optimistic trial run yesterday, I can't see any cry of betrayal sticking. This isn't 1979 - a Tory government is in office at present and a general election is an opportunity to remove it. It'll hardly be the SNP's fault if Labour and the Lib Dems prove to be too rubbish to take that opportunity. And it remains to be seen whether they will prove to be too rubbish - the electorate has been incredibly volatile in recent years and surprise election results have almost become the norm.
UPDATE: The last two paragraphs are moot now that Corbyn has backed a general election (literally within the time it took to write this blogpost!). It's safe to assume he wouldn't have done that unless he'd known the vote was going to pass anyway - he couldn't go into an election campaign being seen to be scared of losing. So that shows the value of the SNP not following the reverse Bain principle - sometimes a bold stance can force Labour to back down.
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I simply cannot understand why Mr Campbell is once again pushing the self-destructive narrative that the SNP and/or pro-indy parties in general need a majority of the vote for a mandate, and not just a majority of seats. For months he's been loudly calling on them to use their current mandate to call a pre-2021 indyref (and I agree with him on that) and yet that mandate was won without an outright majority of the popular vote. Look up the 2016 election result if you don't believe me. So why would we suddenly and needlessly start setting ourselves a much tougher threshold for future elections? It makes no sense at all.