The sudden appearance of Barack Obama seemed at first a miraculous solution to the party's problems. He was a fresh face, charismatic and charming, without a long list of enemies (truth to tell, without a long list of much of anything except degrees from elite schools and a rather unimpressive career as a law professor at the University of Chicago). More importantly, he was technically black - actually the issue of a white American mother and a Kenyan immigrant who deserted his wife shortly after Barack was born. For decades now, liberals in the United States, and particularly left-leaning Democrats, have been dying to find a black candidate for the presidency who did not scare the pants off them. Obama seemed just black enough - he had established his political base in Chicago's large African-American community - and just white enough (he speaks Standard American English) to fill the bill. The fact that he had been in the US Senate for less than four years - half of which he has spent campaigning for the presidency - did not seem to bother them. He represented a ready-made escape hatch for those who feared being dragged down to defeat by anti-Hillary sentiment.

Even more important, Obama brought to the table the Democratic party's largest single constituency - and its most reliable. In many states blacks constitute as much as 40 per cent of the Democratic vote, and their churches make up an informal but vital network for getting people to the polls. Under some circumstances the black vote can make Democrats competitive in states such as Kentucky, Tennessee, Virginia and even Georgia, all of which normally go Republican in presidential years. Combine this constituency with liberal elitists in the affluent suburbs of American cities and university towns and you have a singularly sophisticated political brew. The Clintons underestimated the potency of this coalition to their peril. Perhaps the defining moment of the primary season came when Bill Clinton arrogantly wrote off Obama's victory in the South Carolina primary by comparing it to Reverend Jesse Jackson's earlier feat in the 1984 race. By so doing he committed the unpardonable sin of questioning Obama's "post-racial" credentials, offending the candidate's black and white supporters in equal measure (although for quite different reasons).