Now, 16 months later, Cindy Sheehan, 48, is camped outside George Bush's ranch in Crawford, Texas, demanding to see the president. "I want to ask him why did my son die? What was this noble cause you talk about? And if the cause is so noble, when are you going to send your daughters over there and let somebody else's son come home?"
She plans to stay throughout August if she has to. "I want people to realise that we are a nation at war and only a few of us have to pay for it. I want to put the war back on the front page where it belongs."
Ms Sheehan has met the president before, a few months after Casey died. She describes his behaviour as "disrespectful" and "inappropriate", saying he kept referring to her as "mom", could not remember Casey's name and acted as though he were at a party. According to Ms Sheehan, Mr Bush said he could not imagine losing a loved one like an aunt or uncle or cousin. She reminded him that Casey was her son.
Ms Sheehan, who campaigned against Mr Bush's re-election and has participated in commercials opposing the war, says she "probably expected him to act the way he acted".
She and her band of 15 or so supporters cut an unusual sight perched between ranches on Prairie Chapel road. Along the two-hour drive from Dallas, the symbols of American nationalism become increasingly overt. Discreet "Support our troops" ribbons tied to SUVs turn into bumper stickers decrying "aid and comfort to the enemy".
Along the George W Bush Parkway, the flags - like the sky and the portions - get bigger. In Crawford itself, the message "Let Freedom Ring" is emblazoned outside the Yellow Rose store.
But at Ms Sheehan's makeshift home, the bumper stickers and posters have different messages - "Draft the twins", "Hail to the thief", "No blood for oil", and "Support the troops - bring them home." There have been some altercations with local people and the police.
While a meeting with the president remains unlikely, Ms Sheehan has captured the nation's attention. Early yesterday she addressed Good Morning America; CBS and CNN have been to see her already. A magazine photoshoot was followed by an interview for a New York radio station. Her message has resonated. Other bereaved mothers are on their way to join her.
Ms Sheehan also has a captive audience in the White House press corps, which is holed up in Crawford waiting for something to happen.
The interest in Ms Sheehan's efforts seems to reflect a shift in national mood. More than 60% of the country is in favour of withdrawing troops, and a recent poll by AP-Ipsos showed approval of Mr Bush's handling of Iraq at 38%, its lowest level yet. The death last week of 20 marines from one battalion has also raised public concern about the mounting number of US casualties.
Yet Ms Sheehan's presence could yet turn into something far more potent than a media story in a quiet August. Mr Bush has thus far tried to keep a distance between himself and the war dead.
He writes to each family and sometimes meets family members, but the president never attends funerals or greets coffins. His supporters say he was offended by what he regarded as Bill Clinton's occasionally gushing public performances, which Mr Bush felt turned private grief into political gain.
But with an articulate, persistent bereaved mother on his doorstep, this approach could begin to look aloof.
In a sign that the Bush team is aware of the potential for Ms Sheehan's campaign to capture the sympathy of the American public, the president sent 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.
Mr Hadley told her the president "really cares" about men and women in uniform. Ms Sheehan replied: "You can't tell me that because I've met with him and I know that he doesn't care."
