So now we know. Either Barack Obama or John McCain will become the 44th president of the United States. Both were written off by the pundits, yet each emerged as the compelling candidate for his party. Why? And what is there to be learned from this extraordinary primary season?
The tendency is to draw the wrong lessons. Much has been made of the symbolism of the Democratic contest, seen as a choice between different ways of making history, rather than a battle of ideas. Yet those closer to the action see things very differently. In private, veterans of the Clinton White House describe Hillary's campaign as a last stand for the New Democrat formula, forged during Bill's time in office. Speak to Obama's team and you hear ambitions not just to win the race, but to redraw America's electoral map. The reality is that a new way of doing politics is emerging. I draw three big lessons.
First, 2008 has seen a decisive rejection of the "political class". Both McCain and Obama came from outside a political establishment rooted in the language and methods of the 1990s. McCain, whose tour bus is known as the Straight Talk Express, draws on both his life before politics and his outsider's perspective on Washington. Obama makes a virtue of his recent arrival on the national stage, something people once regarded as a weakness. Launching his campaign last year he declared: "I know I haven't been in Washington for long, but I've been there long enough to know it has to change." Both Obama and McCain are distinct from a political elite seen as aloof, managerial and distant from the people it represents. For Westminster, these are lessons indeed.
Second, both nominees refuse to be bound by artificial ideas. McCain champions immigration reform and pushes the Republicans on climate change; Obama says he is prepared to open up a dialogue with Iran. This is not political cross-dressing, but its opposite. The American public is gravitating towards candidates who define themselves against the challenges they face - climate change, mass migration, a war-torn Middle East - and not the old adages about "tough on national security" for Democrats or "no-go areas" for Republicans. If politics in the 1990s was steeped in political positioning, the campaigns of 2008 seem much closer to people's everyday lives. People are wise to triangulation: they want to be listened to and involved, not managed.
Third, we are seeing new ways of creating a political movement. Yes, the soaring speeches and the well-crafted adverts remain, but there is much more here than meets the eye. Obama's campaign has raised more money from small donations than from large donors, giving it an air of popular authenticity and collective ownership. He has also spent his money differently - putting resources into grass-roots organisations, spurring countless young people to take part for the first time. And Obama's web strategy is premised on connecting activists and supporters to one another, not just pushing out tightly controlled messages from campaign HQ. Following the false start of Howard Dean's campaign, the internet has come of age. All this works because the principles are right. Obama's campaign has at once lowered the barriers to entry into politics and consistently raised the expectations of what can be achieved when people are willing to take part. A far cry from our political parties' reliance on membership and rigid structures.
Suddenly politics looks very different across the Atlantic. It involves different people, from the candidates themselves through to first-time volunteers. It relies on neither old dogmas nor the political handbooks of the past decade. And it is founded on new ways of bringing people together, whether in local organisations or through the web. Lessons from America cannot, of course, be glibly transposed on to a very different way of doing things over here. But if the primary season in America - and the intense interest it has provoked in Britain - prove anything, it is that the politics of the long 1990s is finally being consigned to history.
David Lammy is the minister for skills