IT WAS the week that Barack Obama became the Democratic nominee. Hillary Clinton saw it happen, in the press, on television, on the floor of Congress itself, but she pretended not to notice. Despite huge debts and long odds, she will fight on until the last vote has been counted.

When Obama visited the House of Representatives the day after his crushing victory in North Carolina, her supporters shamelessly stole into his aura. Congresswoman Yvette Clarke asked him to sign a copy of the New York Daily News headlined It's His Party. Congressman Alcee Hastings embraced him like a brother. Both are nominally Clinton superdelegates.

Republicans know their enemy. Karl Rove's column in the Wall Street Journal declared: "It's Obama, warts and all." Talk radio host Rush Limbaugh, whose Operation Chaos urged conservatives to prolong the struggle by voting for Clinton, told listeners: "I now believe Obama would be the weakest of the Democrat nominees He can get effete snobs, he can get wealthy academics, he can get the young, and he can get the black vote, but Democrats do not win with that."

Obama's team hinted he would spend more time in general election swing states from now on. Campaign manager David Plouffe said: "We can see the finish line." They calculate that on May 20, the votes of Oregon and Kentucky will be enough to secure a majority of pledged delegates under the party's rules.

Clinton loyalists dispute the sums. Her principal strategist Howard Wolfson dismissed the minimum winning number of 2025 delegates as "a phony number" because it doesn't include Florida and Michigan. On Thursday, Clinton wrote an open letter to Obama urging him to support "a solution that honours the votes of the millions of people who went to the polls" in the two disputed states.

The Democratic Party's rules and bylaws committee will meet on May 31 to decide what should be done. Before then, unless her dispirited supporters stay at home, Clinton will thump Obama in West Virginia, one of America's poorest, whitest states. She will almost certainly win Kentucky a week later by a wide margin. Demographically, the two states correspond to districts in Pennsylvania where she beat Obama by around 30%.

In an interview with USA Today, Clinton explicitly invoked race within the core argument of her candidacy. "Obama's support among working, hard-working Americans, white Americans, is weakening again," she said.

"I have a much broader base to build a winning coalition on There's a pattern emerging here." West Virginia and Kentucky can reinforce that point.

Clinton is convinced she is the stronger candidate in the three biggest presidential election swing states, Pennsylvania, Ohio and Florida. She feels she has been robbed of a legitimate victory in Florida and deprived of a rust-belt contest in Michigan. She has another month to make her case to voters, and three primaries she should win to look forward to. But most of all, she will see it out because, in the words of North Carolina's governor, Mike Easley, she "makes Rocky Balboa look like a pansy" and cannot or will not admit defeat.

Her followers have enthusiastically adopted the boxing metaphor that she introduced with an image of Sylvester Stallone running up the steps of the Philadelphia Museum of Art. Two people on the podium at her Indiana victory speech wore boxing gloves. The danger is that in her legendary capacity to take a punch she resembles Muhammad Ali - a great champion who was permanently damaged by pride, stubbornness and a few fights too many.

On Tuesday night, she opened with a disingenuously cheery interpretation of events. "We've come from behind, we've broken the tie," she said, "and thanks to you, it's full speed on to the White House." Three paragraphs later she was asking for money. As a sign of desperation, it was almost as bad as the all-white crowd standing behind Bill and Chelsea. The glaring flaw in her claim to electability is that black voters have utterly abandoned her. They too will be a key constituency in November.

Wednesday's revelation that she has lent her campaign another $6.4 million was another sickener. Her finance director, Terry McAuliffe, told journalists "Senator Clinton has anted up and is fighting on," but he has been suspiciously quiet about online fundraising totals. The full extent of her debts will be revealed on May 20, when April's finance report is made public.

Obama's victory address in North Carolina showed that he believes he has won the nomination. The contrast with his subdued, lethargic speeches in Texas and Pennsylvania, dressing up a loss as a draw, could hardly have been more acute. His tone was conciliatory, his target John McCain. "Many of the pundits have suggested that this party is inalterably divided," he said, "that Senator Clinton's supporters will not support me and that my supporters would not support her. Well, I am here tonight to tell you that I don't believe it.

"This fall, we intend to march forward as one Democratic party, united by a common vision for this country, because we all agree that at this defining moment in our history we can't afford to give John McCain the chance to serve out George Bush's third term."

If this hopeful reverie glossed over exit polls that showed him winning just 34% of the white blue-collar vote, the rest of the speech showed how much he has learned during two months of unrelentingly populist campaigning. His new message, forged on the road in Pennsylvania, Indiana and North Carolina, is a direct response to Clinton's attempt to portray him as an elitist who loves his country less than he should.

The hand-picked gallery of supporters standing behind him carried the Stars and Stripes as well as "change we can believe in" placards. There was no flag pinned to Obama, but he wore his patriotism well, to the point of wearing it out. He eulogised "the America I love the America we believe in the founding ideals that the flag draped over my father's coffin stands for." He mentioned America 52 times in 20 minutes.

The stories he told cast him as a product of hard-scrabble aspiration, the son of "a single parent who had to go on food stamps", whose father-in-law put in overtime to send his daughters to college because he believed in a country that "rewarded work and the workers who created it."

Every anecdote drove home his unsubtle change of tack. He spoke of a woman who lost her pension in Indiana, a student working the night shift in Iowa, a bereaved army mother in Wisconsin and a jobless Pennsylvanian marooned at home by the price of petrol. The way he strummed mystic chords of empathy was worthy of Bill Clinton himself. Hillary's negative strategy has divided Democrats, but by forcing Obama to confront his failure to connect with working-class Americans, she has done him a favour.

On Friday Obama crossed an important symbolic threshold when New Jersey congressman Donald Payne switched sides. For the first time, he now has more superdelegates in his column than Clinton does. The shower of high-profile endorsements that many analysts predicted after Tuesday's results never materialised, but the steady drip of support continues.

Senior Democrats are not inclined to force Clinton out. John Edwards skirted the issue of whom he voted for in North Carolina on MSNBC's morning show, despite some determined fishing. Al Gore maintained his diplomatic silence. Democratic National Committee chairman Howard Dean stuck to his position that the nominee would be decided by June, and Nancy Pelosi, speaker of the House, declared the race "alive and well."

George McGovern told Clinton to quit for the good of the party, but coming from the archetypal liberal loser it probably didn't sting too much. More hurtful was the lukewarm backing of fellow senator Dianne Feinstein, one of her most loyal advocates, who told congressional newspaper The Hill "I'd like to talk with her and get her view on the rest of the race and what the strategy is."

Few doubt that the endgame has begun. The way Clinton runs in the remaining primaries will set the terms of the deal. If she pursues what Air America Radio host Rachel Maddow described as a "scorched earth" strategy, it will lend credence to the view, expressed openly on left-wing blogs and in coded language by the mainstream media, that she is prepared to destroy Obama for the chance to take on McCain in 2012.

If she chooses to negotiate, she will do so from a position of strength. The party badly needs her supporters, and the way to retain them is to allow her to exit gracefully. Clinton could demand a major policy concession, such as the mandate for universal healthcare in her manifesto. Buying the good behaviour of a rival is an established tradition in US politics, so Obama could also pay off her debt, even though much of the estimated $15 million would go to her hated former adviser Mark Penn.

The most intriguing prospect, of course, is the dream ticket. Obama will certainly have plenty of opportunities to practice the magnanimous yet non-committal answer he gave CNN on Thursday: "She is tireless, she is smart. She is capable. And so obviously she'd be on anybody's shortlist to be a potential vice-presidential candidate."

In her Indiana speech Clinton repeated that "no matter what happens, I will work for the nominee of the Democratic party." Until she does, she is hurting her reputation and Obama's chances a little more every day.