By the way that is a picture up top of Shiek Sattar. Without him creating the Anbar Salvation Council there would be almost no police in Anbar and there would be few if any tribes fighting al-Qaeda.
Thanks. He looks like a real ball of fire. :') The hanging of Saddam Hussein shook things loose, I believe. FIrst, al-Sadr is widely believed to have carried out the hanging as the denouement of a feud; second, the gov't in Baghdad then (finally) gave the go-ahead for the US to bust up the Mahdi army, and al-Sadr fled like the overweight cowardly demagogue that he is.
The third reason is, there's a widespread belief that Iran will be a lot more effective in launching an insurgency in Iraq, given the widely-believed myth of what they accomplished through their Hizzie proxy in Lebanon. This is genuinely alarming to the Sunnis.
The Sunni leaders could have been on board with this long ago. As they come aboard now, I think we'll all see how smart it was not to shoot them all down like dogs.
Of course, I still would have preferred that, but that's just me. ;')