Three weeks on, where do we stand? Three weeks ago, the Liberal Democrats were assembling in Bournemouth, while the administrator was working over the weekend to pull the plug out of the big socket at Lehman Brothers in Canary Wharf. Three weeks ago, the Prime Minister's hold on office seemed precarious as a minister, a whip and several Labour MPs had resigned from Government posts to demand a leadership election.
How different the landscape looks now. The financial crisis of which Alistair Darling, the Chancellor, tried to warn us in the interview in his croft over the summer, suddenly threatened to overwhelm the US political system. Its effects on the so-called real economy are still muted, but its impact on British politics was dramatic.
This newspaper was the first to detect a "Brown bounce" even before the opening of the Labour conference in Manchester, thanks to a well-timed ComRes poll that found that most people thought the crisis was the wrong time for Labour to think of changing prime minister. That poll also recorded a sharp drop in David Miliband's share price before the Foreign Secretary set foot in Manchester. The stage was set, therefore, for Gordon Brown to raise his game and use the economy to invite the voters to cling to the skirts of his experience for fear of something worse. Which he did, with some help from his wife, who introduced him with affecting sincerity, and from Mr Miliband, who managed to slip on the skin of his own banana.
Despite a little local difficulty over the premature announcement of Ruth Kelly's departure from the Cabinet, Mr Brown did enough in Manchester to rally his party and put his internal critics on the defensive.
That success, and the surprise rejection by the US Congress of the $700bn bailout plan on Monday, presented David Cameron with a more difficult task than he can have expected at the Conservative conference in Birmingham. As a result, Mr Cameron's messages were mixed. On Tuesday, he made a sombre attempt to muscle onto the news bulletins by offering Mr Brown support for which he had no need, while George Osborne, the shadow Chancellor, returned to London to watch the crisis unfolding on the television in his office. Then in his big speech on Wednesday, Mr Cameron suspended his bipartisan approach to blame Mr Brown for having caused the crisis, or, rather, for having made it worse in Britain. And he threw some red meat to traditionalist Conservatives in the hall, going through what Alan Watkins calls today "the Daily Mail bumper fun book of politically correct idiocies by public officials in obscure bodies".
Mr Cameron's was a plausibly prime ministerial speech, but Mr Brown held the strongest card in the game of conference sequencing. It might be thought unfair that the Conservatives get to go last. Nick Clegg, the Liberal Democrat leader, must certainly think so: he made a good speech at the start of the conference season, but his opinion-poll gain has been washed away like a sandcastle on a beach. In government, however, Mr Brown can trump the Opposition with a reshuffle, and he used it to spring an October surprise. Nobody, not even Peter Mandelson himself, expected him to bring such a long-standing enemy back into the fold.
Whether he needed to do so is a moot point. He had already solidified his position, and Mr Cameron's conference had been overshadowed by the news from the markets. Mr Brown betrayed an unexpected gambler's mentality, going for "double or quits". It will either reinforce Mr Brown's image as a "serious person" pulling together a team of all the talents to handle the economic challenge; or it will throw away all that he has gained in the past three weeks by giving the impression of desperation.
We are inclined to give him the benefit of the doubt. There is something to admire in Mr Brown's determination to defy expectations. The most dangerous idea for him is that the pluralism and openness of his first weeks as Prime Minister was a synthetic phase; that is over now and he cannot change his basic political personality; and that he is therefore doomed to lose the next election. By bringing Mr (soon to be Lord) Mandelson back, he has certainly confounded settled assumptions about his character, as the bearer of grudges and cultivator of favourites.
He recognises, as perhaps some of his critics do not, that the British electorate is hostile to him – although not as hostile as it was three weeks ago – but that it is not yet positively enthusiastic about the prospect of a Cameron government. Say what you like about Mr Brown, he cannot be faulted for trying his utmost to change people's minds.