Surging optimism among Democrats about regaining the White House this year has been tempered by fresh warnings that the battle between Hillary Clinton and Barack Obama risks turning into a bloodbath before the Denver convention in August.

The Democratic race has already smashed all records for turnout and fundraising, with millions of new voters and hundreds of donors galvanised by the historic choice of picking either the first black or the first female presidential nominee.

Caucuses in Wyoming on Saturday had a sevenfold increase in the numbers taking part compared with 2004, while Democrats also celebrated winning the Congressional seat vacated by Dennis Hastert, the former House speaker — a victory some compared to toppling Saddam Hussein’s statue in Baghdad.

Howard Dean, the chairman of the Democratic National Committee, yesterday said that such results showed why his party was on course to defeat John McCain, the Republican nominee-elect, in November’s general election. He added, though, that elder statesmen might yet have to talk to Mr Obama and Mrs Clinton “about how to make peace and the convention work”.

A race like a crackpot Dynasty

The contest between Barack Obama and Hillary Clinton matches any fiction

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Nancy Pelosi, the House of Representatives Speaker, has urged them to keep their “eyes on the main prize” — and not turn off the American people.

Gary Hart, a former presidential candidate, said that Mrs Clinton’s attacks on Mr Obama’s credentials as a commander-in-chief have “severely damaged” the latter, whom he hopes will be the Democratic nominee.

Samantha Power, Mr Obama’s adviser who was forced to resign last week for branding Mrs Clinton “a monster”, has caused further embarrassment by casting doubt on his plan for withdrawing troops from Iraq. The Clinton campaign spent much of the weekend circulating these comments as evidence that Mr Obama is all words, no action.

Mr Obama’s aides have responded by accusing Mrs Clinton of telling lies about his foreign policy and running a “scorched-earth” strategy against him. A campaign memo describes her failure to disclose tax returns as confirming Mrs Clinton to be “one of the most secretive politicians in America”. It asked: “You have to wonder whether she’ll be open and honest with the American people as president.”

Although Mr Obama won Wyoming by 61 to 38 per cent, he made a net gain of just two convention delegates. Tomorrow’s primary in Mississippi, where more than a third of the electorate is likely to be black, should give him another win.

It is almost impossible for either candidate to win the nomination without support from a large portion of the 794 super-delegates, many of whom are now biding their time to see who is best placed to win the general election.

Mrs Clinton’s campaign is putting pressure on Mr Dean to allow a rerun of primaries in Florida and Michigan — both of which she won in January — but where the 366 delegates are banned from the convention because of a dispute over party rules.

Mr Dean suggested yesterday that he was sympathetic to the idea of a postal ballot in both states, which could help Mrs Clinton to take the lead in the popular vote. Mr Obama, although publicly promising to abide by whatever the rules require, is said to be arguing that the delegates for the two states should be split evenly with Mrs Clinton.

A new poll yesterday indicated that the candidates are tied in Michigan but that Mrs Clinton leads Mr Obama by 55 per cent to 39 in Florida.

Mr McCain, meanwhile, is concentrating on raising money for the election and working out how to “maintain the visibility” of his candidacy while the spotlight will be on the Democratic race.

But although his February fundraising total of $12 million (£6 million) is dwarfed by the $80 million that was generated by the two Democratic candidates, Republicans say that Mrs Clinton and Mr Obama appear intent on spending their money driving up each other’s negatives — “and doing our work for us”.

Ken Mehlman and Karl Rove, who masterminded President Bush’s victory in 2004, are now acting as informal advisers on Mr McCain’s campaign, it was reported yesterday.

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