Pro-war commentators characterised her as a "nut" who was being manipulated by the left. The internet gossip Matt Drudge inaccurately claimed that Cindy Sheehan "dramatically changed her account" of one meeting she had with Mr Bush. That claim was then picked up by Fox News and repeated on Slate's website by the columnist Christopher Hitchens. Hitchens accused Ms Sheehan of "spouting piffle" and lambasted her protest as "dreary, sentimental nonsense".

Personal attacks on her were set to grow yesterday after her husband of 28 years filed for divorce, citing "irreconcilable differences". Patrick Sheehan, who was her high school boyfriend, is seeking a share of insurance money and benefits awarded by the US government after their soldier son's death in Iraq.

Ms Sheehan, 48, whose vigil in Crawford, Texas, has attracted huge media coverage throughout the US, has become a lightning rod for both pro- and anti-war campaigners during the past two weeks.

Her son Casey was killed when his unit was attacked by insurgents in Baghdad in April 2004. She wants to meet Mr Bush to discuss the war.

Several other parents who have lost their children in the conflict have joined her protest, as polls show public opposition to the war growing. However, Ms Sheehan has constructed a formidable media machine of her own.

TrueMajority, an anti-war group founded by Ben Cohen, one of the founders of Ben and Jerry's ice cream, has hired a Washington public relations firm to work with Ms Sheehan. And Joe Trippi, the man largely credited with Democratic hopeful Howard Dean's early success in last year's presidential election campaign, organised a conference with Ms Sheehan and liberal internet bloggers.

Despite her domestic rift, Ms Sheehan, from Vacaville, California, refuses to leave her makeshift peace camp in Crawford, which has been dubbed, "Camp Casey" until Mr Bush meets her.

The president, who is spending his summer holiday at the ranch, has expressed sympathy for her, but refuses to meet her. He did however send the national security adviser, Stephen Hadley, and the deputy White House chief of staff, Joe Hagin, to talk to her for 45 minutes.

Ms Sheehan was not impressed. "I think they thought I'd be very impressed and intimidated that these two high-level officials came to talk to this little grieving mother, and that I'd leave," she said.

Her presence has become a growing problem for the White House, which does not wish to seem heartless to a bereaved mother, but does not wish to be seen giving in to a demand from anti-war protesters.

Tension increased around her campsite yesterday after a pickup truck ran over wooden crosses erected at it, and residents petitioned county leaders to prevent large gatherings near the president's ranch.