Barack Obama came out on the steps of the statehouse of Des Moines Iowa tonight around 9.15 pm there. Here, almost six months ago, he had staged an upset win of the caucus, the first of the primary contests of which Hillary Clinton had been the heir presumptive.

At the time Iowa was hard to read. Was it a freak result, derived from the taxing caucus process which required people to spend a midwest winter evening in a school gym, arguing about health care programmes? Or was it a harbinger of something else?

We didn’t need to wait long on that. Though Hillary took the New Hampshire primary, Obama quickly put her on the defensive with a string of wins – in southern and caucus states – which not only put her on the defensive, but made the Clinton brand seems suddenly old, tarnished, dull, the graveyard of the political imagination.

Leading up to Super Tuesday, the politics of the two contenders became asymmetrical, Obama talking to a universalism, a sense of abstract ideas more lofty than any previous contender has appealed to.

Hillary, having no capacity to match his soaring rhetoric had no place to go but deeper into the ground, tunnelling Vietcong style, making a virtue not only of a prosaic politics, but of a shameless strategy, channelling a barely suppressed frustration from many of her supporters at the idea that, at the very moment when ‘one of them’ – leaving aside the veracity of that claim – was in reach of the presidency for the first time, it was to be snatched from them by a lithe, sleek young man, the student prince.

With Obama’s delegate count rising remorselessly, and superdelegates peeling away from her, Clinton’s continued march — based on a virtually identical programme – took the campaign into white water territory, a place of pure anguish where the outline of the terrain disappeared altogether.

Health care, poverty, the war, ceased to be the issue – it became a competition around the rules of the Democratic party, popular vote versus delegates, party rules versus states’ rights.

She has been enormously destructive, but to be fair, what else could she do? A closed political party would resolve its programme and its leader seperately and would have plumped for Obama long earlier – or for Clinton herself, even earlier back, and at least settled the matter.

Faced with the chaotic primary process, how could she not stay in to the bitter end? For the last six weeks, victory and survival have, for Hillary Clinton, been equivalent terms.

So when Barack Obama announced a few days ago that he would be in Iowa on the evening of the Oregon and Kentucky primaries, Clinton knew it was an attempt to drive a stake through her heart, by coming back to where it all started in the winter, to claim the victory based on passing a simple majority of pledged delegates.

So it proved, sort of. “In the fullness of spring” Obama told a packed crowd of mostly lumpy midwestern white people “we have returned with a majority of delegates elected by the American people.” And the kiss of the whip “we have travelled here with one of the most formidable opponents” before going into a paean to Hillary sounding pretty much like the moment when the passenger door swings open, and the hitcher is sent tumbling into the ditch.

So there was no direct claim of victory – Obama gave something better, the assumption of it. Having rolled smoothly over Hills he launched into the most extended attack on John McCain that he’s given to date.

With the Oregon polls yet to ‘close’ (it’s a 100% postal ballot so closing is a funny idea), on the basis of his projected win, or even on the third or so of delegates he’ll pick up from his 65 – 30 loss in Kentucky, he has effectively withdrawn from the primary race. It’s over for him. For Obama, tonight was when the general election campaign began.

For Hillary, it’s going to be a lonely, bitter, desperate last fortnight in the great plains of South Dakota and Montana, winding up in the non-state of Puerto Rico, an island-size case of welfare dependency if ever there was one. She has to stay in and fighting based on nothing other than the possibility that something will happen and, should she get the nomination, she will be able to say that she never gave up on herself, and thus would never give up on America.

Her speech, given about as soon as she indecorously could in Kentucky, weren’t bad but she was wise to get in before Obama’s, knowing she wouldn’t top his. It just had to be done, to buckle down for the final fortnight.

And then what? Would she fight on past June 4 into the hiatus period, if Obama was still short of the 2026 absolute majority? If she had that, would she claim that the real absolute majority had to factor in the unseated Michigan and Florida delegates? It seems unimaginable, but so would have most of her tactics 6 months ago, from all the mathematical fudging to the noxious dogwhistling to ‘hardworking white people’.

With Oregon likely to return around a 56-44 result for Obama, there is no new news in the exit polls. Kentucky Clintonistas don’t like Obama, big news – because, as one vox popped blue grasser said “they want Obama to be less black” (Christ – if this diffident nerd were any less black he’d be Senator Steven Fielding). But of course, primaries are self-selecting processes, and so once again a statistic whose significance is literally and exactly unknowable is being taken as gospel for the sake of news. There undoubtably will be a Clintonista leakage to McCain – just as there will be an influx of first-trime voters to support Obama.

God oh God it’s one thirty in the am and the headline act still haven’t taken to the stage. Political junkie is one thing, political masochism another. Please now can we move on from what began in Iowa, to begin what ends in the White House?