BAGHDAD — A growing number of Iraqis blamed the United States on Sunday for creating conditions that led to the worst single suicide bombing in the war, which devastated a Shiite market in Baghdad the day before. They argued that the Americans had been slow in completing the vaunted new American security plan, making Shiite neighborhoods much more vulnerable to such horrific attacks. The critics said the new plan, which the Americans have started to execute, had emasculated the Mahdi Army, the Shiite militia that is considered responsible for many attacks on Sunnis, but that many Shiites say had been the only effective deterrent against sectarian reprisal attacks in Baghdad’s Shiite neighborhoods. Even some Iraqi supporters of the plan, like Hoshyar Zebari, the foreign minister who is a Kurd, said delays in carrying it out had caused great disappointment. In advance of the plan, which would flood Baghdad with thousands of new American and Iraqi troops, many Mahdi Army checkpoints were dismantled and its leaders were either in hiding or under arrest, which was one of the plan’s intended goals to reduce sectarian fighting. But with no immediate influx of new security forces to fill the void, Shiites […]