The 'Surge' Is Succeeding

This according to Robert Kagan, writing in the Washington Post:

Some observers are reporting the shift. Iraqi bloggers Mohammed and Omar Fadhil, widely respected for their straight talk, say that "early signs are encouraging." The first impact of the "surge," they write, was psychological. Both friends and foes in Iraq had been convinced, in no small part by the American media, that the United States was preparing to pull out. When the opposite occurred, this alone shifted the dynamic.

As the Fadhils report, "Commanders and lieutenants of various militant groups abandoned their positions in Baghdad and in some cases fled the country." The most prominent leader to go into hiding has been Moqtada al-Sadr. His Mahdi Army has been instructed to avoid clashes with American and Iraqi forces, even as coalition forces begin to establish themselves in the once off-limits Sadr City.

I also believe the strategy of 'clear and hold', of US troops sticking around even after the enemy leaves, is the main cause of the turn around.