Mr Brown's decision to resign was designed to "unlock" a possible coalition deal between Labour and the Lib Dems, says the BBC's political editor Nick Robinson.
Clegg may well loathe Brown more than other possible Labour leaders, but does he really have the stomach for unending ‘Clegg props up another unelected PM’ headlines?
The timetable for Brown to be replaced goes up to autumn. A coalition decision is need this week. If Clegg does a deal with some caretaker leader, he’ll know that his partner risks losing the job within a few months. And very obviously Labour’s views on the coalition it would find itself in would be a key feature of the leadership election.
I guess there’s the idea that Clegg himself could be PM. That was an interesting fancy when his party was in second place in the polls a while back, but now it seems like a tasteless joke. And the Labour party would never wear it.
One reason Labour’s offer to the Lib Dems can’t in practice be as appealing as it might sound is that a good 10-20% of Labour MPs are utterly against proportional representation. With the best will in the world, any Labour leader would struggle to deliver a vote for anything more than a referendum on AV, which the Lib Dems regard as only slightly better than FPTP.
And regardless of who’s Labour leader, to have a majority in parliament, a Lib-Lab deal would need to involve at least another two minor parties. This would be hard to hold together and much likelier to collapse into a second election sooner, at which the Lib Dems would find their right-leaning supporters deserting them for the Tories.
If Clegg is, as reported, really stepping up his discussions with Labour, then either he’s out of his mind or it’s just a bluff to squeeze a better deal out of Cameron, or he’s just putting on a show for his left-leaning, Tory-hating members, so he can say that at least he looked into that option.
I hate to say it, but Cameron will be PM and he’ll get there with some sort of Lib Dem support. Very soon.
(NB My predictions are usually wrong.)