John Rentoul: That's the last challenge to Brown. Pity...

David Miliband seemed to have flunked his final chance to go for the top job, but his long-term chances are unscathed

One of David Miliband's supporters, a former cabinet minister, summed up last week to me thus: "Something which wasn't going to happen now isn't going to happen." Well, Gordon Brown has not yet made it to the finishing line, but it is hard to disagree. Two other former cabinet ministers, Patricia Hewitt and Geoff Hoon, did what they set out to do. They wanted to give their colleagues a "clear opportunity to finally lay this matter to rest", as they said in their email on Wednesday, and Labour MPs took that opportunity, albeit not in the way that the plotters intended. If Hewitt and Hoon wanted clarity, they have come closer to it.

We have learnt that, after two and a half years of Gordon Brown as Prime Minister, the only people left in the Cabinet are those with safe seats that have decided, at differing levels of their consciousness, to go into the election with him at the helm. This was always a provisional judgement, and last week it was tested. The line wavered, but it held. We should be in no doubt, however, that the plot, dismissed by even Blairite MPs to whom I spoke last week as "hopeless", "cack-handed" and "self-indulgent", could have succeeded. If David Miliband had wanted to bring Brown down, he could have done so.

The trouble with that, from Miliband's point of view, was that he was most unlikely to emerge from it in a better position than he is in today. If there were no other resignations and Brown managed to hang on, his political career would be over. But if other ministers followed and more MPs demanded a secret ballot, and Brown finally came out with his hands up, the most likely beneficiary would still not have been him; it would have been Alan Johnson, the Home Secretary. Mr Clean Hands has more support among Labour MPs, and would have fought the curtailed leadership election as the unity candidate. Some of those people that are now saying Miliband is a serial bottler would praise his courage, but they would be offset by others that thought he was being treacherous. Indeed, the surest way by which Brown could have been ousted would have been if Miliband had resigned and said selflessly that he wanted Johnson as prime minister.

But the point about a big resignation – Johnson, Harriet Harman, Alistair Darling and Peter Mandelson are also powerful enough to bring Brown down – is that it could have been done at any time before Christmas, which would have been the best time. They have all thought about it, and last week's plot was an attempt to bounce one or more into doing it, but they don't want to, and now we know.

It is a long time since I read Sigmund Freud on the psychology of humour, but it is notable that Brown, having not made a single funny joke in public since he became Prime Minister, started to deploy his secret weapon in the Commons last month. Then on Thursday, after the Hewitt-Hoon coup had failed, he opened an event saying, "Yesterday I didn't think I'd be here – we were supposed to do this launch in Southampton." Talk about the expression of feelings that are otherwise taboo. They are all there: fear, relief, triumph, gloating. Above all, perhaps, relief. Brown knows that last week was probably the last of plotting; the only thing that will dislodge him now before the election would be an external shock.

That is a shame. The Labour Party has a democratic duty to present to the voters at the election the best possible alternative to David Cameron. Brown is not it. The opinion poll evidence may not be strong, but YouGov on Friday found that Miliband as leader would cut the Tory lead from 12 percentage points to eight. Johnson would cut it to nine. (Ed Balls would increase it to 13.) But the party is not behaving rationally. Freud is a better guide to its workings than rational choice theory.

The consolation is that the instant verdict that David Miliband is seriously damaged is mistaken. His reputation has been harmed, of course, not so much by his seven-hour delay in rallying to the Prime Minister's cause on Wednesday but by his patent lack of enthusiasm when he did so: "I am working closely with the Prime Minister on foreign policy issues and support the re-election campaign for a Labour government that he is leading."

Oh, for goodness sake, everyone said. Either strike to kill, or get on with it. "He was trying to be truthful," explained a friend. Never mind that, said an irritated world – the same world that usually complains about politicians not being honest. More important, though, this friend points out that his reluctance will "look very different on 7 May". That is the point. Miliband is still standing, and after the election he will still be the front runner for the succession. It is important that he should be. If Labour in opposition turned to his brother or to Ed Balls, it would lurch to the left and could be out of power for a long time. David Miliband is the best hope of the party's early recovery and return.

Other important things are happening beneath the surface of last week's plot. We report today evidence of a new alignment in the party between Jon Cruddas, the most important figure on the left, James Purnell and Miliband. Just as significant was the attack on Ed Balls last week by John Harris, The Guardian writer who is an influential voice in the left-wing Compass group, as representing "the most conservative and unpromising strand of Labour thinking".

Miliband was damaged in 2007 when he failed to stand against Brown; he was damaged in 2008 when he slipped on his own banana. "But he was right not to stand and lose," points out his friend. After that, "people said David's finished, but he's still there".

Miliband did not handle last week's fourth unsuccessful attempt to force Gordon Brown out of office with style or good grace. But the idea that his show of reluctant loyalty has destroyed his chances of the leadership is overblown. He is still there.

John Rentoul blogs at www.independent.co.uk/eagleeye