When Cindy Sheehan burst on the national scene, it was as an aggrieved mother whose son had died in Iraq. Plainspoken and unscripted, Sheehan delivered an easily relatable story that gave her a kind of moral authority. Since then, some have questioned whether Sheehan has strayed too far politically. In January, she denounced President Bush as a terrorist while standing alongside Venezuelan President Hugo Chavez, an ally of Fidel Castro's who has said he is prepared to repel a U.S. invasion. The same month, she was arrested at the State of the Union address for wearing a T-shirt reading, "2,245...