Josh Buermann in comments here

An immediate withdrawal like you advocate would probably be deadlier for US troops than the actual way out. Over 70% of Iraqis want a timetable, same for Americans. A unilateral, "precipitous" withdrawal isn't the best way to manage the outcome. The ISG's disengenuous ploy was to bait-and-switch the policy actually preferred by most Americans, Iraqis, the insurgency, the government, Iraq's neighbors, and Democrats with the precipitous withdrawal supported by a few frustrated American nationalists.