Last week's loss of the Senate seat held for so long by Edward Kennedy leaves Barack Obama's Presidency looking hobbled almost before it has got into its stride.
Instead of basking in the adulation of a Democratic majority that his own campaign helped to elect Mr Obama will find Democrats newly fearful of losing their seats later this year. After all, if a Republican can win in Massachusetts how safe are they? Mr Obama will have to persuade and inspire all over again.
Yet the depression that has settled on the Democratic camp since last Tuesday seems excessive. To extrapolate from this one result that the Democrats will lose control of both Houses of Congress in this year's mid-term elections (as Bill Clinton did two years after his election), or that Mr Obama is already doomed to be a one-term President in the manner of Jimmy Carter, smacks of very un-American defeatism.
There were special factors that made the Massachusetts seat vulnerable. One was the complacency that led the Democrats to nominate such a weak candidate; another was the sense of entitlement that led them to assume until too late that the seat could not be lost. Then there was the disillusionment with mainstream politics, carried over from the Bush years and exemplified in the so-called Tea Party movement that welled up from the grassroots.
Only then do you come to Mr Obama's inadequacies - or what voters felt were his inadequacies: a mismatch between words and deeds on the economy, dithering on Afghanistan, and above all his controversial healthcare reforms.
But it is in his policies that salvation lies. Helpful critics have recommended two emergency responses. The more adversarial chide Mr Obama for not making more of George Bush's negative legacy. The new President was politically naive, they say, in believing he could build a cross-party consensus. He should now go out and lambast the Bush years while the memory is still just about alive.
The other course, proposed even more insistently, is that Mr Obama needs to "move to the centre" before it is too late - as Mr Clinton did only after losing both Houses of Congress in 1994. By trying to govern from the left, they say - the left as defined by its place on the US political spectrum, which is a good deal further to the right than in Europe - Mr Obama is sacrificing any chance of realising his agenda. Only if he gives more ground to his opponents will he garner enough support to pass, for instance, a version of his healthcare legislation, and so improve Democrats' prospects at the mid-terms and his own chances of re-election in 2012.
This advice, though, ignores several realities. The first is that Barack Obama was elected on a platform that reflected the priorities of the left. This gives him his mandate to govern. Democrats had a more centrist candidate in Hillary Clinton, but they rejected her. If Mr Obama or his party is losing elections this could be because popular sentiment has shifted. But has it?
Might it not rather be that a quorum of Obama voters feel that he has not pursued his original agenda urgently enough? Guantanamo remains open, US troops are still in Iraq, and the banks seemed to have slipped off the hook. Add healthcare reform, which is extraordinarily difficult for any US politician to enact because the insured majority fear they will lose as an improvident minority gains, and the second reality is clear. In Massachusetts a weak Democratic candidate was caught between Republicans still smarting from their rout last year and Democrats disappointed that Mr Obama had not made more progress in the direction he had promised.
And there is a third reality: more than a year after John McCain's defeat the Republican Party lacks both a plausible leader and an obvious Presidential candidate. And no, since you mention it, Sarah Palin is not the one.
Obama's cause is not lost by a long way and his well-wishers will do him a grave disservice if they succeed in convincing him that it is.