So we're in a tight UK General Election campaign now, and one which Labour still hopes to win. The odds are rather against that they will, but they still might - to the party's long-term detriment.
Imagine it. Labour with a very slender working majority, dependent on the Liberal Democrats as coalition partners - and on Plaid Cymru, Northern Ireland's SDLP and especially the Scottish Nationalists for vote-by-vote support. A government on a life support machine, just like Labour was in 1976-79 - the last time its social democratic views seemed to be fading out of British public life for good.
That might represent a perfect storm - if you want to see Labour eviscerated for good. Like Pasok in Greece, or Germany's Social Democrats (to a lesser extent), in those circumstances Labour might just be reduced to the electoral fringe and to irrelevancy.
That's partly due to Labour's own agenda for power. Now there is a big difference between Labour's relatively mild plans for spending reductions and the Conservative ones (not that the latter are at all realistic, but we've covered that before). A difference that will never, ever see the light of day if Labour are in a position to take over No. 10 in just a few short weeks. And which will leave Labour with the dread tag of 'austerity' hung around its neck by parties that have very few alternatives, but a lot of good slogans.
That would be a perfect recipe for the United Kingdom Independence Party to hollow out Labour's dominance of the North of England, just as the Scottish National Party seem to have done such a good job of political cleansing in Scotland. The SNP seem poised to make fundamental breakthroughs in May that might end Labour's dominance of the Scottish electoral landscape for good - and set us on the road to another independence referendum. That's partly because Labour took Scotland for granted for so long, and they've done exactly the same with their big majorities in England's old industrial heartlands.
What the SNP's extraordinary and unprecedented electoral advance tells us is this: there's no such thing as a safe seat any more. We saw that in the Heywood and Middleton by-election last autumn, when UKIP nearly obliterated a big Labour majority.
Labour has a lot of seats that are pretty vulnerable to a UKIP surge on anything like the same lines as that being enjoyed by the SNP right now. Hull East. Easington. Great Grimsby. Hartlepool - anywhere where there are large conglomerations of older men without any qualifications. The left behinds. The angry. The frustrated. The disenfranchised. Voters with not much to lose - and who might think that Labour haven't done that much for them for decades. Voters who have much in common with Scots in Greater Glasgow whose patience might just finally have snapped with what they see as a 'Westminster elite' who've never listened to them very much anyway.
Up until now, UKIP have been taking most of their votes from those who plumped for the Conservatives in 2010. But that hides the real dynamics, for many of those come from Britons who opted for Labour in 2005, and even more of them from those who thought of themselves as 'Labour' in the 1990s. As soon as Labour was back in power, UKIP would move its heavy artillery from the South of England - and away from Conservative targets - and just trundle it all Northwards.
So let's go back to the imaginative picture with which we began. Labour will be imposing limited, but still quite painful, austerity. Its Scottish wing will just have been absolutely hammered, partly because Labour has become seen as a party of orthodox economics imposed from outside Scotland. Scots will just have voted (again) against such ideas. But they will still have got Labour telling them what's best for them. Expect Scottish Labour to recover from there? Well, no.
And there'll be 'supported', if that's the right word, from the Opposition benches by (say) 30 or 40 SNP MPs who have absolutely no stake whatsoever in seeing them succeed. Quite the opposite, in fact, for if relatively progressive and humane government can be delivered within the UK, why leave it? Ed Miliband as Prime Minister (above) would expect to be brought down by those SNP MPs just as soon as they can - unless it's in their interests to let him bleed support and authority within a fixed term Parliament from which it will be difficult to escape.
And all the while Labour will be hemorrhaging support to UKIP in the North of England. The party will be trapped between its own voters, two parties that loathe it with a passion, and the logic of power. They won't even possess the freedom of action that an overall majority (and a mandate) can provide. It might become a long, cold, dark old nightmare.
For all these reasons, anyone who wishes Labour well might think to themselves: a good election to lose, this one.
