US voters punish Obama
This is a stinging setback for a president who was elected with so much hope and so much exuberance just two years ago. But it is more than a rebuke. It will stop him turning his plans into laws.
At the root of the defeat for his Democratic Party, undoubtedly, is the painfully slow economic recovery - which means many of those who propelled him to power are disappointed and disgruntled and stayed at home.
But that's only half the story.
At the heart of the Republican revival is the rise of the angry and energetic Tea Party movement - the fiscal puritans who say government is too big, doing too much. It is they - President Obama's ideological opposites - who have won the day.
Certainly two of their highest-profile, not to say eccentric, candidates did not succeed in Delaware and Nevada - perhaps costing the Republicans a couple of scalps, and perhaps undermining the woman who supported them, Sarah Palin.
But overall this conservative movement is in charge, with the man who is likely to be the Republican speaker in the House, John Boehner, telling them "I will never let you down".
Mr Obama's fall from grace has been hard and fast. He has been pulled to Earth by an electorate that is deeply divided, by a politics that has become tidal.
Perhaps the president, and many of the rest of us, over-interpreted what his victory two years ago really meant.
Perhaps it was nothing but a ringing endorsement of a couple of abstract nouns, rather than of a man and his policies - a vote for the ideal of hope, the concept of change, a rejection of George W Bush and a wish to embrace someone who wasn't for war and wasn't impulsive.
If Mr Obama and his Republican rival John McCain had swapped policies, I suspect America would still have voted for the young guy with lots of energy rather than the old bloke who didn't seem to understand economics.
Mr Obama has indeed admitted: "I am like a Rorschach test," referring to the inkblot technique used by psychologists. Voters saw their deepest hopes; now some see their darkest fears.
It isn't really a mark of outstanding arrogance that a man who's just been elected, in a mood of misty-eyed optimism, should mistake this for a mandate.
He couldn't have been clearer about the importance of healthcare reform, his belief the government had a role in improving peoples lives, and his warning it would all take time. But that, apparently, is not what a lot of people were buying.
It may be he is going against what a lot of Americans want for their country. For every Tea Party supporter who sees his mild social democracy as communism there are probably several more who don't characterise it in extreme terms, but don't like it any more for that.
It didn't help that the bail-outs of the banks and the car industry were disliked by left and right. To the left, they were helping the rich and powerful corporations which helped create the mess. To the right this was a Big Government takeover of the economy.
There was some terrible politics. Regardless of its merits or otherwise, health care reform looked like a muddle, badly sold, badly explained - and the eventual bill was the mangled result of the sort of horse trading people thought they were voting against.
Some are against stimulus spending on principle. But those who might have supported it couldn't see where the money was going, how it was being spent.
Having spent ages trying to find projects to illustrate TV reports, I know the money seemed to trickle into the sand into petty projects or invisibly plugging holes in the spending of individual states.
By all this he has been undone, at least for now. For much will depend on how he and Republicans play the second half of the match.
President Obama is due to give a news conference later on Wednesday, and no doubt he will talk of compromise and coming together. But it will be difficult to compromise with a party and movement that intends to gut his programme.
One must not exaggerate. Bill Clinton, as president, coped with a Congress of a different colour. So did George W Bush and Ronald Reagan. But there is now a bigger gulf than ever between the parties.
This does not spell the end. As we've just learnt a lot can happen in two years. In 2012 Mr Obama will be running against a man or a woman, not a movement and a feeling.
But for now it seems Senator Obama warned himself, and understood the dangers of the powers he was summoning. The hopes he raised do indeed seem too audacious for the times.