Almost half of Americans could never bring themselves to vote for Hillary Clinton in a presidential election, according to an opinion poll published yesterday which shows how much of a struggle the former first lady faces.

The CNN poll will alarm the Clinton camp after finding that 47% of those questioned would "definitely not vote for" the New York senator - a negative score that towers over the two Republicans most favoured to oppose her in the 2008 election. Only 30% of respondents said the same about Rudy Giuliani, and 34% about John McCain.

US Senator Hillary Rodham Clinton , a Democrat from New York, is pictured here addressing the Campaign For America's Future "Take Back America" conference 13 June, 2006 in Washington, DC. Some Democrats are having second thoughts about Hillary Clinton as their 2008 presidential candidate, wracked by doubts about her cross-party appeal, and disappointed by her position on US troops in Iraq . (Photo: REUTERS/Kevin Lamarque)

"This is the kind of number that only goes up as campaign controversies accumulate," said Larry Sabato, the director of the Centre for Politics at the University of Virginia. "It would mean she'd have to run a near-perfect campaign in the best possible circumstances in order to win.

"Is that impossible? No. For all we know there'll be a Democratic landslide. But the last one was in 1964. They don't happen very often."

The fading hopes of some Democrats that Al Gore might mount a challenge from the left of Ms Clinton will fade further with the news that he scored worse in the poll, with 48% negatives. Ms Clinton did, however, have the highest positive number, with 22% saying they would "definitely" vote for her. The worst performer of all was Jeb Bush, who received a 63% negative score, though he is highly unlikely to put himself forward.

"If 47% of people say they won't vote for her, that's 53% of people who'll consider it, so she's got a chance," said the pollster John Zogby. "I would not say that about any other person, but those of us who have seen her campaign know that she has the capacity to turn non-believers into believers."

Ms Clinton has been burnishing her hawkish credentials on foreign policy in an effort to win over centrist voters, as part of a strategy that critics say relies too perilously on winning every single "blue", or traditionally Democrat-supporting, state, plus one or two marginals.

But she will have to fight distrust in the conservative south and midwest, as well as memories of the divisive political climate during her husband's presidency.

The nightmare scenario for the Democrats is one in which Ms Clinton sweeps through the nomination process, only to find herself unable to win. Fear of that outcome might yet render her seriously vulnerable in the primary stage of the election.

Guardian Unlimited © Guardian Newspapers Limited 2006

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