War Driven By Political Goals Rather Than Victory
Really dumb strategic move from a military standpoint. Eliminate all elements of surprise and give plenty of time for escape. Was the real goal a military victory or a political one? If the objective was to apply enough pressure to cause surrender, their move was probably the best one. I would think however, that by now it should be obvious there isn't going to be a peaceful solution to the Sunni insurgents.
Regards,
Mark