Ali approaches me at a Friday prayer service in Sadr City. He wants to talk. A U.S. missile, he says, hit his house in May and killed his two sisters and badly wounded his mother. He is a member of the Mahdi militia and can no longer return home for fear the Iraqi army will arrest him. He is careful not to be seen talking to me, since unauthorized contact between us could get him in serious trouble with the militia. We quickly arrange to meet a few hours later at my hotel, and then he shakes my hand and walks away, disappearing again in the crowd of thousands of worshippers.