Sadr one, Americans nil

Remember Fallujah? In response to the murder and mutilation of four US mercenaries, the Americans invaded the place, killed 700 civilians, and then withdrew after it became apparent that they weren't going to get what they wanted. Well, the same is happening in Najaf: after demanding for weeks that Moqtada al-Sadr disband his militia and turn himself in, waging war in Shia Islam's most sensitive areas, damaging several major shrines and killing numerous innocents, the Americans are now... withdrawing because they're not going to get what they want.

It was obvious from the beginning that this was not a battle the US could win politically. So why did they fight it in the first place? Pressing hard and expending so much effort has made them look like losers - and pissed off a hell of a lot of people in the process.