"U.S. officials say the decision of some tribal leaders to begin going after insurgents reflects growing public anger over attacks that have killed or injured more than 8,000 Iraqis, according to local government figures. They also say there has been growing alarm on the part of some tribal leaders over insurgents' demands for adherence to strict Islamic law. U.S. military leaders say that alarm has inspired a sense of partnership that didn't exist earlier.

"It's only frankly been the last six months that they've recognized two things: One, they can't do it themselves, and two … they had much more in common with the coalition than they do with Iran," said a senior U.S. military official, who spoke on condition of anonymity. ..."