This article in yesterday's Washington Post on Iraqi refugees returning to Baghdad was accompanied by this graphic of the new sectarian make-up of the city. Comparing Baghdad's sectarian distribution in April 2006 to November 2007, we see a city completely transformed, with a majority of the formerly mixed neighborhoods now taken over by Shi'is, most of them supported by the guns of Muqtada al-Sadr's Mahdi Army.
What the graphic does not show, and the article does not mention, are the concrete walls which have been erected between new Sunni and Shia neighborhoods throughout Baghdad. David Axe reported in April on the walling off of Adhamiyah:
Not everyone was thrilled by the Adhamiyah barrier. "This will deepen the sectarian strife and only serve to abort efforts aimed at reconciliation," a Sunni shop owner told The New York Times.
Noting such objections, [General David Petraeus' counter-insurgency advisor David] Kilcullen stresses that the walls are temporary. He compares them to tourniquets. "It's something you do when patient is bleeding to death. But you don't leave it there forever or it causes damage."
Eight months later, these tourniquets have been applied throughout Baghdad, essentially making permanent the ethnic cleansing of the last few years, and ensuring that resentments will continue to stymie Iraqi political reconciliation for the foreseeable future. I'd offer that the tourniquet is also an excellent metaphor for the surge itself: It's helped, in some respects, to stop the bleeding, but it's made it impossible to save the leg.