"What may have partly enabled the success now after so long was Khalilzad's efforts to patch up relations with Sunnis.
"At the same time, the Jordanian-born al-Zarqawi, who was sensitive to U.S.-encouraged derision of a foreigner killing Iraqis, began cozying up to Sunni insurgents. It was probably the move that led to his undoing, said Ed O'Connell, a retired Air Force intelligence officer who led manhunts for Osama bin Laden and others in Afghanistan, Iraq and Yemen.
"'Once that happened, all we needed was a guy inside the insurgency to tell us where he was and, bam, we got him,' he said."
Regular readers know this has been building for awhile. You have tribal leaders who resented losing authority to outsiders, and others willing to reach a deal of some sort with the coalition and Iraqi government which would almost have to involve cooperation against terrorists. This cooperation may be a turning point, even if the actual death of Zarqawi is not.
UPDATE: For some reason, posting this caused my original "Zarqawi is dead" post to disappear. All well - you all know what happened.