Sheehan delivered her brief remarks in front of a mock graveyard laid out on the lawn beside the Independence Visitor Center, with ersatz headstones representing 636 Americans who have died in Iraq this year.
Later, in a hurried conversation with reporters, she discussed what she said would be the main focus of her life in the months ahead: an attempt to defeat House Speaker Nancy Pelosi (D., Calif.) in Pelosi's San Francisco district next year.
A California resident, Sheehan plans to run as an independent. She announced her candidacy Monday night after Pelosi failed to meet Sheehan's deadline for backing an impeachment effort.
The Democrats "won't hold George Bush accountable, so we have to hold the Democrats accountable," Sheehan said.
Sheehan, whose son Casey was killed in Iraq in 2004, became famous in the summer of 2005 when she staged a 26-day roadside vigil near Bush's ranch in Crawford, Texas, seeking in vain to talk with Bush about the war.
Two months ago, she announced her retirement from the peace movement. But she reversed that stand this month and targeted Pelosi.
She appeared on Independence Mall after supporters (including Delaware Valley Veterans for America, which arranged her visit) and protesters (including A Gathering of Eagles, another veterans group) spent nearly two hours in the midday sun - with tempers and the rhetorical heat rising.
When Sheehan finally arrived, protesters shouted, "Media whore!" When her backers shouted, "Impeach! Impeach!", protesters responded with "Shame! Shame!"
"They're using our troops as political props," said Wayne Lutz of Glenside, a 10-year Army veteran and supporter of the war, referring to the fake headstones. "Most of the parents of those kids would be devastated to know they're being used like that."
Contact senior writer Larry Eichel at 215-854-2415 or leichel@phillynews.com.