In the Republican race, former New York mayor Rudolph W. Giuliani, who recently made clear his intentions to seek the presidency, has expanded his lead over Sen. John McCain of Arizona. Giuliani holds a 2 to 1 advantage over McCain among Republicans, according to the poll, more than tripling his margin of a month ago.

The principal reason was a shift among white evangelical Protestants, who now clearly favor Giuliani over McCain.

“It would be one thing if Giuliani could say, ‘I’m a strong social conservative in my private life’, but he can’t even say that,” said Ramesh Ponnuru, a conservative commentator and author of The Party of Death, an attack on social liberalism. “It’s not just the fact of his multiple marriages, it is the way the Hanover marriage melted down. It was operatic.”

When Giuliani met Hanover on a blind date in the early 1980s, his first marriage to Regina, his second cousin, was already over. Hanover, who went on to appear in the television series Ally McBeal, was a glamorous soulmate who seemed to enjoy the spotlight as much as he did.

They had two children, Andrew, 21, and Caroline, 17, but in 1996 Hanover stopped calling herself by his last name and a year later Vanity Fair magazine said that he was having an “intimate relationship” with a senior member of his staff.

In 2000, without telling Hanover first, Giuliani announced at a press conference that he was separating from her. She retaliated by accusing him of being unfaithful with the employee, but he was already with Nathan.

Maggie Gallagher, a family values campaigner, was outraged by Giuliani’s “scummy” performance, accusing him of making Bill Clinton “look good as a husband and father”.

New Yorkers learnt during the divorce case that their cancer- afflicted mayor was temporarily impotent and Hanover demanded a huge settlement, including £760 a month to care for Goalie, the family’s golden retriever.

Felder struck back, accusing Hanover of being an “uncaring mother” who was “howling like a stuck pig”.

In the end Giuliani, who was beginning to earn big consultancy fees after September 11, agreed to a settlement of $6.8m to avoid the full horror of a court case.

Hanover has married Ed Oster, her university sweetheart, and written a book, My Boyfriend’s Back, about rekindling an old romance. Even if she stays mum, there is enough in the public domain to rattle conservatives. Yet however vicious the personal attacks on Giuliani, they are unlikely to dent his reputation for competence. He did, after all, handle the September 11 attacks while bunking with gay friends in the midst of an affair and a divorce battle.