From the Guardian (of all places): “Many Sunni insurgent leaders are beginning to doubt the wisdom of their alliance with al-Qaeda extremists.” Also:
Rami [a former Sunni insurgent] was explaining how the insurgency had changed since the first heady days after the US invasion. “I used to attack the Americans when that was the jihad. Now there is no jihad. Go around and see in Adhamiya [the notorious Sunni insurgent area] – all the commanders are sitting sipping coffee; it’s only the young kids that are fighting now, and they are not fighting Americans any more, they are just killing Shia.” …
Abu Omar told me. “In my area some ignorant al-Qaeda guys have been kidnapping poor Shia farmers, killing them and throwing their bodies in the river. I told them: ‘This is not jihad. You can’t kill all the Shia!…Why provoke them?’ … He was wrestling with the same dilemma as many Sunni insurgent leaders, beginning to doubt the wisdom of their alliance with al-Qaida extremists. … Another insurgent commander told me: “At the beginning al-Qaida had the money and the organisation, and we had nothing.” But this alliance soon dragged the insurgents and then the whole Sunni community into confrontation with the Shia militias as al-Qaida and other extremists massacred thousands of Shia civilians. Insurgent commanders such as Abu Omar soon found themselves outnumbered and outgunned, fighting organised militias backed by the Shia-dominated security forces. …
Then he said: “I am trying to talk to the Americans. I want to give them assurances that no one will attack them in our area if they stop the Shia militias from coming.” This man, who had spent the last three years fighting the Americans, was now willing to talk to them because he saw the Americans as the lesser of two evils.
More here.