Oh, you have got to be kidding me:

A U.S. military brigade is constructing a 3-mile-long concrete wall to cut off one of the capital’s most restive Sunni Arab districts from the Shiite Muslim neighborhoods that surround it, raising concern about the further Balkanization of Iraq’s most populous and violent city.

U.S. commanders in northern Baghdad said the 12-foot-high barrier would make it more difficult for suicide bombers to strike and for death squads and militia fighters from sectarian factions to attack one another and then slip back to their home turf.

Although Baghdad is replete with blast walls, checkpoints and other temporary barriers, including a massive wall around the Green Zone, the barrier being constructed in Adhamiya would be the first to be based in essence on sectarian considerations.

More details at the LA Times story.  So, how much of this has to happen before the Bush administration admits we’re in the middle of a civil war, and losing?