Two years ago Ed Miliband killed New Labour with a speech berating the Iraq war, encroachments on civil liberties and widening inequality. Trouble was, no-one knew what to replace it with.
For months, Miliband walked around with an article by Peter Oborne, the Telegraph commentator, in his pocket. In it, the conservative columnist compared the tax-evading rich to the looting poor, the phone-hacking scandal to welfare scrounging. His central argument was that something had gone wrong at the top and the bottom of British society.
Since then, Miliband has been trying to express that message, to little avail. Today, he found the phrase both for Oborne's thesis and Labour's personality crisis: 'One Nation'.
This was a very smart speech. The phrase belongs to Disraeli, Britain's first Jewish prime minister and a Tory. The strong Conservative associations of the phrase gave the speech a centrist flavour which allowed Miliband to appeal to those who voted Tory in 2010 and play nice with the predominantly right-wing press. The blue stage-backdrop and fluttering Union Jack cemented the impression.
"One rule for those at the top, another rule for everyone else," he said. "Two nations. It's not the Britain we believe in, it's not the Britain this party will ever be satisfied with. New Labour, despite its great achievements, was silent about the responsibilities of those at the top. In 'One Nation' responsibility goes all the way through society. In 'One Nation', no interest - from Murdoch to the banks - is too powerful to be held to account."
This one rhetorical mechanism allowed Miliband to appease the right and articulate a political viewpoint which will find sympathisers on the left. The idea that moral fibre is failing at the top and the bottom is political gold: You can express it while keeping almost everyone on board. It's like 'we're all in this together' but with substance. And it helps that no-one identifies themselves as the bottom or the top.
To this, Miliband added the Olympic spirit of the summer, injecting some emotional resonance into what he was saying.
It helps that he was on exceptional form – easily the best he's been in as Labour leader. The easy wit he offers in person was finally translated into his public, political persona. His aides had stopped trying to make him act a certain way. He was utterly himself. He reeled off an attack line about the coalition being a "shower" of incompetents perfectly. He made the audience laugh when he wanted them to. He got them get angry when he wanted them to. It was delivered without notes for well over an hour. In the sections of the speech we'd seen last night, he was word-perfect. It was an impressive feat of memory.
He was in such good form he could nimbly traverse dangerous bits of rhetoric, including one section in which he tried to lure back those who voted Tory in 2010, while simultaneously telling them they were wrong. "I understand why you were willing to give him the benefit of the doubt," he said of the prime minister, "but I think you've had long enough to make a judgement." It looks questionable written down, but it sounded good.
Those expecting an instant game-changer will be disappointed. Conference speeches are radically overhyped. Only really serious political geeks end up watching the whole speech. It will be hard to get voters' attention.
But that is not important. What matters is that Miliband caught political journalists' attention today. A confident, off-the-cuff speech shows he can challenge, if not defeat, Cameron in the 'charisma' stakes. His passionate delivery proves he is not constantly stuck in wonk mode. His use of catchy slogans ("If the medicine's not working, you change it - and you change the doctor too") showed he could formulate a dangerous election campaign. His decision to deliver a risky speech without notes while ahead in the polls proves he has fire in his belly. He will be taken much more seriously.
Most importantly, he formulated the language he will use for the second half of this parliament up to the general election. It is inclusive language which allows Miliband to make a case which a broad range of people could agree with and yet still corresponds to Labour values. It is a massive accomplishment.
The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.