“The political changes that have occurred here and the security problems have led a lot of Iraqis, including me, to change our minds about the withdrawal of U.S. forces,” Mr. Maamouri said. That was a view that few Shiites, empowered by the fall of Saddam Hussein’s Sunni government, would ever have spoken — when it seemed the United States was never going to go.

“They bring a balance to Iraqi society,” he said.

Though Iraqis have called for Americans to leave from the start of the occupation in 2003, the prospect of such a drastic drawdown, from the 48,000 troops here now, has revealed another side of the Iraqi psyche. This is a nation that distrusts itself, with little faith in the government’s own security forces or political leaders. It is as if people here never actually believed that the United States would leave, so all along demands for a pullout were never carefully weighed against the potential fallout.