WHEN Barack Obama spent his last evening before the Nevada caucus addressing a rally at the Nevada University student union, he was conforming to the caricature the Clintons have painted of him as the candidate of the well-educated liberal elite, rather than the sons and daughters of toil – or, as Americans prefer to call them, the hard-working middle class.

It did not help when he told voters that he had bought his wife a glass of champagne the night before on her 44th birthday. “I didn’t realise you could pay that much for a glass of champagne in Las Vegas,” he joked. “If I had known how much it would cost, I'd have had a sip.”

Obama proved, however, that he was just as determined to fight for votes in Nevada as Hillary Clinton. The battle unleashed some of the dirtiest politics of the election, leaving the two candidates spattered with mud and Clinton triumphant as they hurtle towards the Democratic primary in South Carolina this Saturday.

There were rowdy scenes at Caesar’s Palace and other casino sites as the caucuses began. The acrimony spilled into accusations of voter intimidation and name-calling, disputes over President Ronald Reagan’s legacy and charges of inexperience on both sides, with a nasty racial undertone perilously close to the surface.

A race like a crackpot Dynasty

The contest between Barack Obama and Hillary Clinton matches any fiction

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Clinton reached out to blue-collar voters in their workplaces and shored up her base among women by appealing for their sympathy over the scandal of Monica Lewinsky, the White House intern who had an affair with her husband Bill when he was president.

“I never doubted Bill’s love for me ever,” she claimed on daytime television, adding that she respected the right of every woman to make her own decision about how to respond to an unfaithful husband.

After her victory in Nevada, she hopes to wrap up the presidential nomination by Super Tuesday on February 5, when more than 20 states go to the polls. The candidate of the “beer-drinkers” traditionally beats that of the “wine-drinkers” – as her two victories in a row have shown – but the old rules could still be upended by the injection of race into the debate.

When Obama won the backing of the Culinary Workers Union, which organises the housemaids, waiters and bell-hops on the gaudy Las Vegas casino strip, he proved he had some unexpected muscle among working-class and Hispanic voters – key voting blocs in big states such as California, which supplies one-tenth of the delegates to the Democratic party’s nominating convention.

The union’s preference for Obama was a threat to Clinton’s election machine that she dared not leave unchallenged. She hit back with claims that the union had been intimidating voters into supporting Obama and complained about a union-funded Spanish language advertisement that called her “shameless” and disrespectful towards Hispanic people.

One cook alleged that a union representative took away her voter registration card when she said she was supporting Clinton, although she later admitted her English was poor and it might have been a misunderstanding.

Clinton instantly went on the warpath, claiming that voters had been told, “they shouldn’t come or can’t support the candidate of their choice”. She further alleged that workers were threatened with the sack if they did not back Obama, but did not provide any examples.

An irascible Bill Clinton claimed to have personally witnessed voter suppression by union officials with daughter Chelsea and lost his temper when challenged about the lawsuit brought by his wife’s supporters to prevent casino workers voting at their workplace.

Obama sharpened his own critique of the Clintons by mocking Hillary’s claim of having more experience than him. In an interview with the San Francisco Chronicle, he said he presumed it was “through osmosis, as a consequence of having been first lady” because he saw “no management experience” on her CV.

The Clintons’ attacks served to remind voters that they are fighters – a plus when it comes to taking on the Republicans – but also evoked unpleasant memories of how divisive they can be. They forced Obama to spend less time on inspiring rhetoric and more on the warpath, undermining one of the chief sources of his appeal to moderate Democrats and independent voters.

He was pilloried by Clinton for drawing on Reagan for inspiration in an effort to extend his appeal beyond his party. “Reagan changed the trajectory of America in a way that Richard Nixon did not and Bill Clinton did not,” he said. He added that Republicans had been the party of ideas in the past 10 to 15 years. Incensed by the slight to her husband as well as Obama’s ideological heresy, Clinton retorted: “That’s not how I remember the last 10 to 15 years.”

She also dismissed Obama’s credentials to lead the country after he admitted in a televised debate that his biggest weakness was a messy desk. But he turned the tables on her by deriding her claim that “my biggest weakness is I’m so impatient about bringing real change to America”.

“Oh, I’m sorry. I thought the question was about your biggest weakness,” he said. “That’s what happens when you’re in Washington too long. You don’t speak English any more.” David Axelrod, Obama’s chief strategist who is steeped in the tough politics of Chicago, blamed the Clintons for the negative tone of the contest. He said he was disappointed to see the former president “descend from the high place he’s been and become an attack dog”. He also alleged that anonymous leaflets were circulating at the university rally calling Obama the candidate of the “casino bosses”.

In the crowd Sean Hobart, 37, an Obama supporter and stay-at-home father, said: “I used to be a big admirer of the Clintons but they’ve been dirtying the pool. I’m seeing them do things I used to defend them over when they were in power.” But he was pessimistic about Obama’s long-term prospects of winning the nomination: “We’re seeing the same old political machine at work that used to wag the dog.”

Axelrod conceded that Obama faced a difficult road ahead, particularly among Hispanic voters. “We’re just not as familiar [to them],” he said. “We need to build a familiarity and it’s a challenge, because we don’t have much time.”

Rosena Lamell, 25, an African-American who works for a travel company in Las Vegas, said the Clintons had the same relationship with Hispanics that they used to have with black people: “She’s been going into their communities door to door, just as she did with us in the 1990s, but we have our own candidate now. It’s all a facade. You can tell because as soon as Obama became a threat, she started to twist and turn every word he said.”

The most poisonous row continues to be about race. The issue blew up when Clinton appeared to belittle Martin Luther King as a civil rights dreamer rather than a doer, and was inflamed when one of her leading black supporters baited Obama by drawing attention to his use of drugs as a young man.

The Republicans were beginning to dream of waltzing off with the main prize while the Democrats fell out over race and gender. But if the behaviour of the two Democrat camps seemed suicidal, it was because the stakes are so high. African-American voters could still tilt the race in Obama’s favour, but at the risk of sending anxious white voters in Clinton’s direction.

William Galston, an elections expert at the Brookings Institution in Washington, said: “There has been a pattern in the Democratic party going back 50 years between upscale reformers and ‘regulars’, who are more interested in material issues.” From Adlai Stevenson to Gary Hart, Paul Tsongas, Bill Bradley and, in 2004, Howard Dean, the reformers have always lost.

“Barack Obama fits into that tradition with one salient exception,” said Galston. “African-American voters have always been with the ‘regulars’ but, if they are with Obama, it changes the balance of power. It is very nearly an even fight, the most even I have seen in my lifetime. This is going to be one for the history books.”

Both camps have got out their calculators for Super Tuesday. Clinton’s advisers believe they are on a clear path to win the greatest number of delegates and “super delegates”, made up of Democratic party notables, who wield the voting power at the Democrats’ national convention.

Doug Hattaway, a Clinton strategist, said in Las Vegas: “This is a national campaign. We like to win and get the momentum, of course, but it is not so much about that as racking up the delegates at the convention.”

States such as California with 441 delegates and New York, Clinton’s home state as senator, with 281, traditionally dominate the convention, but their influence may be partially offset this year by Obama’s increasing strength among African-American voters in the south.

Larry Sabato, professor of politics at University of Virginia, believes that Obama has the potential to put together a winning coalition but it is proving to be too fragile to withstand the Clintons’ attacks.

“Obama has been getting the support of a large majority of African-Americans and a substantial number of white voters who are a little more conservative and attracted by the idea of a uniter,” he said.

Sabato suggests that the Clintons have been playing the race card against Obama in the hope of driving a “wedge” between black and white voters: “It is so obvious what they’re doing. They’re telling African-American voters, ‘You know an African-American can’t win so vote for us as the next best thing’, and telling white voters, ‘Look, these people are trying to take over. Is that what you want?’ ”

There are signs that white working-class voters in Nevada shifted towards Clinton, including previously Hillary-resistant men. At a rally at a paint company in Las Vegas, Jerald Connor went to shake her hand. Connor, 42, voted for Bush in 2004 because he supports the military, but he is now more concerned about the economy. “My fiancée has just told me that she’s going to vote for Hillary as well and she used to support the Republicans,” he said.

Connor drew the line at supporting Obama, repeating the increasingly common smear spread by viral e-mails that the Illinois senator could be the “Manchurian” candidate – a reference to the film in which the president is a sleeper agent for the communists. “A lot of people will vote against him just because his middle name is Hussein.”

At the same time, some black voters have turned against Clinton because of perceived slights to their race as well as pride in Obama’s performance.

Nearly half the electorate in South Carolina is composed of African-Americans, presenting the first important test of Obama’s strength in his own community. Georgia, a Super Tuesday state with 103 delegates, is another crucial prize. Polls in the state show Obama with a slender three-point lead over Clinton. He is due at an Atlanta church service today.

Shirley Franklin, the mayor of Atlanta, has endorsed Obama, but the Clintons still believe they can win the state. Bill Clinton will be arriving tomorrow and his wife will speak in Atlanta next week.

The Clintons are supported by powerful members of Georgia’s black establishment, including Andrew Young, a former US ambassador to the United Nations. He caused a stir recently when he claimed that Bill Clinton was “every bit as black as Barack” because “he’s probably gone with more black women”.

Older black people are more cautious than the young about shifting their allegiance to the relatively untested Obama.

It is theoretically possible – if increasingly unlikely – that Obama could win more states than Clinton on Super Tuesday but that she will win more delegates. That would boost Obama’s contention that he is best placed to win the support of independents and disaffected Republicans in a general election, and would be used to tempt the “super delegates” to him.

Clinton’s advisers are having none of that. A win by one delegate is a win, they say.

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