It has been interesting watching the Labour party and the media collectively losing their heads over this whole JC thing. The notion that we might actually get a political party that doesn't sign up to the Blairite consensus is interesting, to say the least.
On the one hand, of course, it doesn't matter to me in the slightest. Firstly, simply because I don't have a vote. But secondly because I live in Scotland, and Labour in Scotland are so horrifically awful that I couldn't consider voting for them even if the other JC was their leader. (And neither of the current leadership contenders are even of the calibre of Jim Murphy, so things won't be getting better any time soon.)
On the other hand, though, it really matters who is Labour leader - realistically, the Labour party are the only hope for getting rid of the Tories (on a UK level; Scotland could, in theory, become independent). The SNP (and other nationalists) can't get the numbers, the Greens are effectively nowhere, and the Lib Dems haven't yet realised that they're dead. A new party could, in theory, do the job, but they'd need the Labour party to be removed from the field to have any realistic prospect, or else they're just one more split in the opposition.
Now, there are two possible ways to win an election. One option (the Yvette/Liz/Andy approach) is to try to win back enough of the people who voted at the last election - if they can be persuaded to vote Labour instead of Tory, the government changes. Huzzah! The other option (the Jeremy approach) is to persuade enough people who didn't vote last time that they should, and that they should vote Labour.
Now, in all fairness to him, Jeremy Corbyn does seem to have done quite a good job of engaging a previously-apathetic electorate. And if he does win, that should further engage people - in the same way that the SNP managed to engage people with the independence debate and have grown in support since.
But... will it be enough? The thing is, the Blairite consensus has had politics largely sewn up since 1997, they have massive media support, and they're not going to let that go. (I should note: "Blairite" doesn't mean "Labour" or even "New Labour". It is David Cameron who is the heir to Blair, and both Gordon Brown and Ed Miliband were punished in the media for deviating from that consensus. Just as the Tories would be if they went mad and selected IDS as their next leader again.) If Jeremy Corbyn wins, he'll be subject to a media onslaught that will make Miliband's travails seem trivial by comparison.
If the public are being constantly told by the media, led by the Sun, Daily Mail, and BBC, that Jeremy Corbyn is unelectable and would be an utter disaster if he was, will they turn out in the numbers needed to do it? Or will they vote again for a Tory party that merely has to offer more of the same?
Then again, I can't imagine any of the other three contenders even remotely troubling the Tories either. I'm sure they'll put up a fight, but they'll be offering some reheated flavour of Blairism, up against Cameron's Tories doing the same better, then come to an election against (probably) the inexplicably-popular Boris Johnson, all against a hostile media backdrop. So they'll come a close second in a winner-takes-all two-horse race.
So is it better to go for a safe option that leads to another narrow, but inevitable, defeat? Or is it better to take the big risk and take the option that almost certainly leads to a crushing defeat but might, just possibly, lead to a victory? I genuinely don't know.