For a moment the presidential mask slipped and there, last week, stood Rudolph Giuliani, the feisty New York mayor of old, ready to administer a verbal smack to anyone who crossed him.

A reporter had just asked the front-running Republican candidate a polite question about a scathing magazine profile of his third wife Judith, who is depicted in the September issue of Vanity Fair as a vicious, scheming harpy.

Giuliani’s tortured marital history remains one of his principal handicaps as he vies for the right to succeed George W Bush after next year’s White House polls, yet the former mayor swatted aside the hapless questioner as if he were an impertinent insect.

“Usually most reporters don’t even ask about [private family matters],” Giuliani retorted. “They actually have more dignity than to even ask about it.”

Yet the marital questions are not going away for the man who became a New York hero after the attacks of September 11, 2001. No amount of Giuliani bluster and evasion – which many critics considered to be his defining mayoral traits before 9/11 turned him into a national symbol of courage and resilience – is likely to deflect an issue that may undermine his appeal to conservative Republican voters.

Vanity Fair portrayed Judith Giuliani as a “princess bride” who had worn a tiara to their wedding, who dreamt of queening it over the White House, and who in the past had insisted on reserving a separate airline seat for her Louis Vuitton handbag.

Michael McKeon, Giuliani’s spokesman, denounced the “vile and venomous piece”, which also blamed Judith for breaking up Giuliani’s previous marriage to Donna Hanover, a popular New York actress.

The profile made Judith sound like “a particularly unpleasant combination of Catherine the Great and Britney Spears”, wrote one New York columnist.

It was the latest in a long line of hostile reports on a curiously unsympathetic wife. She was recently described by another columnist as “the bosomy, décolletage-trotting, husband-schnoogling, gold-digging, get-ting-the-man-comes-first every-thing-else-comes-second, three-times marrying babe”. Despite much tut-tutting by veteran presidential campaigners, the 2008 race so far has been marked by unprecedented media interest in spouses and offspring, not least because of Senator Hillary Clinton, whose relationship with her husband Bill, the former president, remains a subject of worldwide fascination.

The Giuliani camp has long been searching for a safe formula that introduces Judith to Republican voters without raking over the messy background of their original romance and the mayor’s divorce. Hanover only learnt she was being dumped when Giuliani mentioned it at a press conference.

At a fundraiser earlier this year, Judith, a former nurse, took the microphone and tried to describe their first meeting, a tricky challenge as Giuliani had still been married to Hanover. She said: “The first time we sat down and talked, I said, ‘What do you know about infectious diseases?’”

It did not help the Giulianis’ cause when Judith revealed the existence of a second exhusband. Between them the Giulianis have been married six times.

The only consolation for Giuliani is that two of his leading Republican rivals – Senator John McCain and former senator Fred Thompson – have also had more than one wife. Questions have already been raised about the current Mrs Thompson’s influence over her actor husband, and the impact her youth and generous cleavage might have on conservative voters.

The other leading Republican contender is the former Massa-chusetts governor Mitt Romney, a Mormon whose grandfather was a polygamist – which may explain why in one recent Republican poll the leading vote-winner was “none of the above”.

Giuliani cooled down enough last week to acknowledge that “the people in this country have a 1,000% right to find out who I am”, adding that the “unfair criticism” of his wife “wasn’t happening because of her; it’s happening because of me”.

But further scrutiny lies ahead. Among questions submitted for a proposed Republican candidates’ debate next month are these from a Texas Republican: “You are all on the record defending the institution of marriage. How many times have you been married? How long? How many marriages are you defending?”

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