What advice does Hillary Clinton have for canvassers in the final days before the Pennsylvania primary? “Oh, just knock on the door and say, ‘You know, she’s really nice’,” the candidate replied.

Then, as the laughter rolling around the room at Haverford College began to subside, Mrs Clinton added: “Or you can say, ‘She’s not as bad as you think.’ ” The brittle, almost regal mask of a woman who had once hoped to glide towards a coronation as the Democratic presidential nominee has long since slipped. What has emerged from behind it is a politician who has as many different faces as golfers have clubs, even if “nice” is not usually among them.

In the course of 24 hours this week, Mrs Clinton could first be seen in Wednesday night’s presidential debate in Philadelphia snapping at the ankles of Barack Obama and then travelling down to Washington for a stateswomanly chat with Gordon Brown.

Then it was back to Pennsylvania for an appearance in front of an elegant marble mantelpiece at Haverford College, where, flanked by her mother, Dorothy, and daughter, Chelsea, she gently explained the importance of a work-life balance. There were cosy anecdotes about her addiction to magazine advice columns and lots of fluent policy details. There was still time to pass on “Happy Passover” greetings to Philadelphia’s Jewish community and film a comedy show cameo as a woman capable of solving any problem before the main event in the evening.

It was at this rumbustious rally in a white working-class corner of Philadelphia that Mrs Clinton demonstrated just how much her own public persona, and the voters whom she attracts, have changed in the past year.

Despite being the mother of a hedge fund manager, she railed against Wall Street. Despite being the wife of the president who pushed free trade deals through Congress, she promised to defend American jobs and back union rights. And then, despite being an icon for working women, Mrs Clinton offered this description for how she would deal with the mess left behind in the White House: “One thing women know is how to clean house, and there is no telling what we’re gonna find.”

Before heading to bed the apparently indefatigable 60-year-old house-wife-in-chief was still able to stand at the bar drinking with her travelling press party and eating chocolate birthday cake for an hour-long off-the-record barroom conversation on international relations that was, occasionally, spiced with her earthy humour.

Mr Obama has, meanwhile, not only become the likely winner of the Democratic race but in doing so has adopted some of the aloofness formerly associated with his rival. At times, he can even appear a bit precious about criticism. On Thursday he complained about Mrs Clinton’s treatment of him at the previous night’s debate. She had been “in her element”, he said, taking every opportunity to “twist the knife a little bit” on questions over his electability. He then airily brushed his shoulder off, as if to say such attacks did not bother him much.

But they do, otherwise the Obama campaign would not respond with such alacrity over each and every charge. He has spent most of the week defending and explaining remarks he made at a San Francisco fundraiser where he suggested that people “bitter” about their economic circumstances “cling to guns and religion”.

The remark could scarcely have been worse-timed, coming before Tuesday’s primary in Pennsylvania, a state where working-class “Reagan Democrats”, conservative on social issues (they like their guns and their God) but economically fearful, are expected to hold sway.

Mr Obama has tried hard to court this group over the past six weeks, but sometimes seems ill at ease away from his core constituencies of black voters and Starbucks-sipping “latte liberals”. On a trip to a rural dairy he looked like a tourist; he failed to finish his beer when visiting a bar; and, most infamously, he scored 37 in seven frames at a bowling alley where he threw gutter-balls.

By contrast, Mrs Clinton has been filmed downing whiskey in Bronko’s restaurant in Indiana, waxing about how she learnt to shoot in Scranton, Pennsylvania, where her father grew up, while alleging that Mr Obama is “elitist and out of touch” with rural white voters.

There is a sepia-tinted quality to her campaign speeches these days as she promises to revive the type of mills in which her grandfather worked, reprise the educational opportunity of the postwar era or recapture the excitement of the Moon missions in the 1960s. “We’ve got to turn America back to its destiny,” she says.

In response to the controversy over Mr Obama’s remarks, Mrs Clinton earns knowing nods from audiences by talking of the challenges she has faced and overcome in life, saying: “You can either get bitter or better.”

Critics suggest that she has become the former rather than the latter in the course of a year in which her own attempts to make history as a woman have been eclipsed by Mr Obama’s bid to be the first black president. There is a sense of resentment at what she regards as the double standards of the US media, swift to jump at any charge of racism but repeating every gender-tainted slight against her.

Yet Mrs Clinton appears to take pride in both throwing, and taking, punches. Not many candidates could have so blithely shrugged when confronted with video evidence showing that the risks of sniper fire that she thrice claimed to have faced on a trip to Bosnia as First Lady were grossly exaggerated.

Veracity and authenticity are qualities that have not always been associated with either her or her husband. However, Michael Nutter, the Mayor of Philadelphia, insists: “Hillary is one of the most down-to-earth people you will ever meet. She looks you straight in the eye.”

Sometimes there is more than a hint of testosterone in her pitch for votes. Yesterday, for instance, Mrs Clinton suggested that her rival had been too thin-skinned over the TV debate. “We need a president who is going to be up there fighting every day for the American people and not complain about how much pressure there is and how hard the questions are,” she said. “When the going gets tough, you can’t run away.”

At her Thursday night rally outside the Mayfair diner, one sign declared: “Real men vote Hillary”. There are, of course, some limits even for a campaign that has developed a taste for red meat. Nancy Poserina, who was holding a homemade banner saying “No peace for terrorists” was told to take it down.

George Dolbow, 45, a glazier who took his 140lb cheesesteak-fed St Bernard dog along to hear Mrs Clinton, could not have been clearer about the choice. “Hillary is for the working people.” How about Mr Obama? “I don’t think he would be good for the working people.”

Mr Obama, a mixed-race child raised without his largely absent father, is clearly irritated at being painted as an elitist by a multimillionaire former First Lady who has spent much of her career sharply at odds with many of these voters. “She’s talking like she’s Annie Oakley,” he said, invoking the gunslinger of the musical Annie Get Your Gun. He added: “Hillary Clinton is out there like she’s on the duck blind every Sunday. She’s packing a six-shooter. Come on, she knows better.”

Even if he loses heavily in Pennsylvania next week, Mr Obama is probably too far ahead in delegate numbers to be caught. But Mrs Clinton’s pugilism here has at least succeeded in raising fresh questions about whether her rival is fit for the fight against the Republicans in November. Four years ago John Kerry, so out of touch that he famously ordered Swiss with his Philly Cheesesteak, lost the white working-class vote by 23 points to President Bush.

John McCain’s campaign was swift this week to seize upon Mr Obama’s remarks on the mental state of the working class, even highlighting his previous accounts of salad-shopping trips to an organic supermarket. The Republican contender’s adviser, Mark Salter, said that it was hard to take seriously a politician “who thinks the whole country is worried about the high price of arugula [rocket] or that you hunt ducks with a six-shooter.”

Hillary’s battling background

— Granddaughter of Welsh immigrants who settled in Scranton, Pennsylvania, and worked in textile factories.

— Daughter of a suburban Chicago small-business owner whom her brother, Tony, described as “confrontational”, and who turned the heating off during freezing Illinois nights.

— Product of a mother, Dorothy, who told her there was no room in the house for cowards when she complained about bullies as a child.

— Outstanding student at Wellesley College where she ruffled authorities wtih her commencement address.

— Law student at Yale, who told the young Bill Clinton: “If you’re going to keep staring at me, I might as well introduce myself.”

— Baby-booming working mother and First Lady who dismissed women who stayed at home to “bake cookies”.

— A figure of hate for the Right, who declared she was no Tammy Wynette – but who still decided to stand by her man.

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