I recall people who Understood Such Things claiming that Labour would never support Scottish Independence because they had no chance of winning a Westminster election without the Scottish seats.
Scotland returns 59 seats to Westminster. Most of them have been Labour for ... gosh ... a very long time. Crucially, since the 70s, a dwindling number have returned Tory MPs. Currently, the Tories have just one MP in Scotland, to Labour's 41.
Well, it looks the conventional wisdom is going to be challenged in 2015.
According to current polling, the Scottish seats aren't going Labour's way. The SNP are predicted to win 54 of the 59. Nothing like this has been seen before. It seems outlandish and impossible that the SNP might actually pull off this insta-rout of Labour. Yet the polls are consistent. the total destruction of the Labour party in Scotland - or something very like it - seems like it is really going to happen.
(Personally, I think the final result will be much less emphatic for the SNP for two reasons. First, a slice of its support may stay at home, and this will swing a few seats Labour's way. Second, some currently saying they will vote SNP may waver; whereas if you're still saying your going to vote Labour in Scotland in 2015, your pretty much definitely mean it.
In spite of those considerations, I still expect it will still be a disaster on an incomprehensible scale for Labour, but with expectations now so low, it may not seem like the catastrophe it actually is - and the SNP may find themselves portrayed as having 'failed' for 'only' winning the majority of seats in Scotland. Such is the berserk nature of the British press.)
And yet, in terms of overall seats at Westminster, Labour still look like finishing a whisker ahead of the Tories.
That's a measure of how crap Cameron's rabble are - they can't even beat a Labour Party that is shorn of Scottish seats and led by Ed Miliband.
It's like Labour are deliberately handicapping themselves, to try and make a fair fight of it.
In spite of all this, however, Nicola Sturgeon and her party are in a precarious position. their support is drawn from three distinct camps: roughly 1/3 actual pro-independence SNP; 1/3 angry traditional Labour voters; and 1/3 Tories and the weird minority of voters who support Lib Dems a for reasons relating to the arcane nature of Scottish politics (henceforth, the Ragbags).
And whatever Sturgeon does, she risks losing a whole chunk of her support. I suspect the crunch issue will be Trident, which Sturgeon has said she will not support under any circumstances.
If the SNP refuse to vote for a bill allocating money to Trident, and she brings down a Labour administration, she'll lose her Labour defectors; they want the SNP to force Labour to behave like Labour, not like the bastard demonic spawn of Tony Balir.
If she supports it, she may lose the Ragbag element, who are more vehemently anti-Labour than pro-SNP. But the loses from this group will probably be fewer in number and may be open to the argument that the SNP is acting in Britain's interest - some of them at least will probably support a nuclear deterrent, for all that they are currently voting for the SNP.
If it comes to a vote on Trident and a Labour government loses, then the administration falls - money bills are always treated as confidence bills. So by knocking back Trident, the SNP topple a Labour government.
It is possible that the Tories could vote for a trident bill; but this seems unlikely The Tories would probably prefer to topple a Labour government. If no new administration can be formed, parliament is automatically dissolved and a new election is called. The Tories would almost certainly walk it, as they would be the only ones who could afford another campaign, and they would be able to campaign hard on "Look what happened when you let that useless shower have a shot. We governed for five years, they couldn't even last five minutes."
After all, the Tories are fundamentally uninterested in keeping the Tories out of power. They can introduce their own Trident bill when they have control of the government benches.
So the SNP get Trident and the rest of us getthe Tories and everyone loses.
Labour could play things smartly and introduce a Trident bill before any further Scottish devolution; because Sturgeon can be fairly certain she won't get much out of the Tories on the devolution front. So she may even end up in the perfect storm of Trident in Scotland, Tories in Westminster, and Devo-Max no-where.
But supporting Trident would be the least damaging option for the SNP. IT would reassure the Labour voters that defecting to the SNP was the right choice; ditto the Ragbags.
The only segment of her voter base she can rely on is the dyed in the wool SNP voters. They haven't got anywhere else to go, realistically, as no other party is offering independence.
Trident is a rat she has to swallow, I think.
If she's fenced herself into a position where she can't actually compromise on it, then she's been foolish.