You young people
To be blunt, the problem is a large majority of Labour MPs in the Commons; it's only going to be addressed by reducing that majority.
But what would that get us, apart from making the Whips work for a living and preventing another disaster like the Prevention of Terrorism Act (which isn't nothing)? The obvious answer is, of course, "Blair out". I wonder about this; I wonder if anything short of a hung parliament would loosen the man's grip on power. But let's go with it: on May 6th Labour is returned with a majority of 35 (say), and on May 7th the knives are out for Blair. And then what?
When I first started thinking about this scenario I came up with all sorts of possibilities involving four- or five-way internecine warfare within the Labour Party: Blairites vs Brownites vs Old Labour (right) vs OL (Campaign Group) vs OL (left but anti-CG)... It could get extremely messy, and extremely interesting in terms of who would come out owing favours to whom. It won't, though, for the simple reason that Blairites are serious about power (as, indeed, are Brownites). As soon as Brown emerged as the front runner (i.e. almost immediately) the Sensational Tony Blair Machine Without Tony would swing behind him, and it would all be over bar the shouting.
Blairites vs Brownites vs Old Labour (right) vs OL (Campaign Group) vs OL (left but anti-CG)... I don't know what possessed me to nominate 'Old Labour (right)' as a runner - most of them jumped ship to either Blair or Brown long ago - but apart from that I think I called it pretty well. 'Old Labour, left but not Campaign Group' won't have their own candidate, but the way they break between the other non-McDonnell candidates will be interesting and may be significant. Watch for the apologias: Alan Johnson is still a trade unionist at heart; Why Brown/Cruddas is the dream ticket...
The last couple of sentences, though... how wrong you can be. There's a song by Peter Hamill which sums up a certain kind of anti-political cynical populism, the kind of sentiment which seems at once radical and common-sense (a combination I always distrust):
Politicians fight it out on the conning-tower
But they all agree not to rock the boat
That's just the trouble with populism: no imagination. I don't see much sign of that gentleman's agreement in the Labour Party at the moment. I see factions fighting like rats in a sack, and be damned to what happens to the country (or other countries) as a result. It's one of those moments when political spectacle starts to present itself as such - compelling but distant, autonomous and utterly unaccountable - so brazen is its participants' disdain for their audience, the voters. It's disgusting, but it's still fascinating. Equally: it's fascinating, but it's still disgusting.
Top tip for any would-be late entrant in the contest: change your name by deed poll to None Of The Above. You'd walk it.