FRESH from her victories in three out of four states last week and surging back in the national polls, Hillary Clinton has crafted a new strategy for winning the Democratic nomination which she believes will legitimise her claim to be president.

Clinton thinks she can win a majority of the popular vote in primaries and caucuses, even if she cannot overtake Barack Obama, her rival, in the number of “pledged” delegates who will vote to choose the candidate at the Democratic national convention in August.

The New York senator has unnerved Obama, who has been left reeling by a series of errors from senior policy advisers. The two opponents face an ugly six-week battle in the run-up to a potentially pivotal primary in Pennsylvania next month.

Democrats boosted Obama in Wyoming last night in state caucuses that gave the Illinois senator a comfortable victory. With almost all votes tallied he beat Clinton by 59% to 40%.

Former senator Bill Bradley, who is a leading supporter of Obama and ran for president in 2000, accused the Clintons of “lying” in pursuit of victory.

“The bigger the lie, the better the chance they think they’ve got. That’s been their whole approach,” he said. “She’s going to lose a whole generation of people who got involved in politics believing it could be something different.”

Bradley believes that Clinton will stop at nothing to tear down Obama even if it boosts John McCain, who was confirmed last week as the Republican nominee: “The Clintons do not do long-term planning. They’re total tacticians and right now their focus is on Obama, not McCain.”

Obama, 46, is threatened by a pincer movement from Clinton, 60, and McCain, 71, as they try to halt his progress with similar arguments about his lack of national security and foreign policy expertise. An Obama insider admitted: “Whenever there’s one person versus two, it always makes things more difficult.”

Clinton’s big win in Ohio has convinced her that she can repeat her success next month among white working-class voters in Pennsylvania, another populous swing state.

It could put her on course to overtake Obama in the total number of votes cast, giving moral legitimacy to her claim that superdelegates – the 796 party leaders, governors and congressmen expected to hold a casting vote – should back her.

A senior Clinton official said: “The momentum is shifting to us right now. If we are the leader in the popular vote and we have closed the gap in pledged delegates, that’s a very persuasive argument.”

The argument is being made privately as winning the most votes still presents a formidable challenge. She might, in the end, have to rest her case on her ability to win key battleground states.

Clinton’s team is divided by backbiting over how to confront the difficulties ahead. No sooner had victory been declared in Ohio, Texas and Rhode Island than officials resumed rubbishing Mark Penn, the chief strategist, for her flawed performance. “A lot of people would still like to see him go,” a senior adviser told The Washington Post.

Top aides such as Penn, Mandy Grunwald, Harold Ickes and Howard Wolfson have such combustible egos, according to one close observer, that “it’s like caging wild beasts together”.

However, the new strategy explains why Clinton is prepared to mount an assault on Obama that risks handing victory to McCain in the autumn. It is worth badly wounding her rival because she believes she has found a way to win.

“If she wins big in Pennsylvania, she can rack up a majority of several hundred thousand votes and be in hailing distance of Obama. So stay tuned,” said Wil-liam Galston, an elections expert at the Brookings Institution.

Clinton’s new tactics depend on clearing up a mess in Florida and Michigan, which are banned from seating delegates at the convention because they defied party rules by holding early primary contests.

Obama leads Clinton by nearly 600,000 in the number of votes cast to date, but trails her by 30,000 if the votes of the two “rogue” states are counted. These states are now likely to stage some form of rerun.

Nancy Pelosi, the speaker of the House of Representatives who will play a critical role in the event of a near-tie at the convention, met leading Clinton officials last week to discuss Florida and Michigan “do-overs”, the role of superdelegates and the campaign’s increasingly vitriolic tone.

Tad Devine, a senior Democratic strategist who has overseen bitter convention battles, said Obama was still the favour-ite to win. “He has a 50-state strategy and she has a 15-state strategy and in the end that may be decisive,” he said. “The most important factor for the superdelegates will be who has the most pledged delegates.”

Clinton will need improbably large victories in the remaining contests to narrow the 100-plus delegate gap that Obama has established. His lead is likely to grow after Mississippi votes on Tuesday.

The former first lady is pum-melling Obama hard in the expectation that he will abandon his signature politics of “hope” for a dirty fight. Her team has accused Obama of behaving like Kenneth Starr, the chief inquisitor of the Clintons over the Whitewater affair in the 1990s, for demanding that she make her tax returns public.

The explosive subject of race is not far from the surface. The internet is buzzing with accusations that Clinton’s team made Obama’s face look blacker on a recent television advertisement challenging his foreign policy credentials.

Clinton mucked in by denying rumours that Obama was a Muslim – then adding the rider, “as far as I know”.

In Mississippi, which has a 36% African-American population, Clinton floated the idea that Obama could be her vice-president. “I’ve had people say, ‘Well, I wish I could vote for both of you’. That might be possible some day, but first I need your vote,” she said.

Clinton was the star guest at the Democratic party’s annual dinner in Canton, Mississippi, but the hall was barely half-full. Underscoring the importance of race and gender in this contest, white women tended to be for Clinton, while African-Americans of both sexes were solidly for Obama. Clinton earned credit for turning up at all – Obama arrives in the state for just one day of campaigning tomorrow – and went on to pledge in a contrived southern drawl that no matter who won Mississippi, “I’ll be there for you”.

However, African-Americans said they would be outraged if she were to rely on the votes of superdelegates to deny Obama the chance to become America’s first black president.

Sylvester Tate, 46, who had travelled for two hours to hear Clinton speak, said: “It would be insulting and ridiculous for them to swing the election to her. I hate to say it, but it would be based on race.”

Ed Rendell, the governor of Pennsylvania who has thrown his support behind Clinton, believes racial issues could affect the vote in his state. “You’ve got conservative whites here and I think there are some whites who are probably not ready to vote for an African-American candidate,” he said last month.

Obama cannot publicly blame racism for the slowing of his momentum, although his team has little doubt in private that it was a factor in Ohio last week. “He has to take a good hard look at why he failed to connect with so many working-class voters,” said Galston. Closing the gap with working-class voters is essential to persuading superdelegates that Obama is capable of going head-to-head with McCain, he added: “McCain is the quintessential ‘white’ candidate – so white that he gets melanoma if he stays in the sun.”

McCain has produced an advertisement comparing himself with Winston Churchill. Just as Britain’s wartime leader vowed to “fight them on the beaches” so McCain, accompanied by grainy film of him in pain as a young prisoner of the North Vietnamese, promises: “We shall never surrender. They will.”

The clip emphasises his patriotism. Karl Rove, former adviser to President George W Bush, observed in The Wall Street Journal: “The interesting intellectual phenomenon is the emergence of the ‘McCainicrats’ – Democrats backing McCain . . . In three recent polls, almost twice as many Democrats support Mr McCain as Republicans support Mr Obama.” An adviser to Obama admitted that his candidate was running into opposition from the kind of blue-collar workers who once supported Ronald Reagan, the Republican president: “Right now, Barack is not connecting with the children of the Reagan Democrats. That’s a real concern.”

The question for Clinton is whether the white working-class voters will desert her for McCain in the general election, even if she is basking in their support for now. The notorious 3am “red phone” television advertisement, suggesting that only Clinton was fit to answer a crisis call at the White House in the middle of the night, backfired last week when a poll revealed that most viewers felt McCain was best qualified to pick up the phone.

The biggest challenge for Obama is to go on the attack without forfeiting his claim to represent a new kind of politics. Campaigning in Wyoming on the eve of yesterday’s caucuses, Obama said he was not going to be “drawn into a knife fight” and used humour to defuse the impact of the “red phone” ad.

“What do people think I’m going to do? I’m going to answer the phone,” Obama said to laughter. “I’m going to find out what’s going on.” But he also charged that Clinton’s style of leadership was “to beat the other side into submission”.

Clinton’s tactics have had an effect. Samantha Power, Obama’s foreign policy adviser, resigned last week after calling the former first lady a “monster”. Austan Goolsbee, his economic adviser, also caused embarrassment by appearing to suggest to Canadian diplomats that Obama’s opposition to Nafta, the free trade agreement, was purely electioneering. In both cases the advisers looked naive – precisely the image that the inexperienced Obama is trying to counter.

Bradley believes that Obama should keep his hands clean but is willing to throw some heavy punches on his behalf. The Clintons have long delayed releasing their tax returns and have refused to name the donors to the William J Clinton Foundation in Arkansas. Archivists are also blocking the release of hundreds of federal papers on White House pardons. “We need to know whether there were favours attached to $500,000 contributions, such as the granting of pardons, squelching an investigation, awarding a contract or deferring a regulation,” Bradley said. “The Democratic party has got to be in dreamland if they think the Republicans are going to let these matters go.”

Benefactors hoping to be rewarded by Clinton need not despair if she does not make it this year. Some cynics believe that she is willing to undermine Obama sufficiently for him to lose to McCain in November, freeing her to take another shot at the presidency in 2012.

Video: Clinton's March 4th speech

Video: Obama March 4th speech

Video: McCain March 4th speech

Video: Huckbee drop out speech