It's a sign of our Orwellian times that the U.S. be described as having pulled out of Iraq while 50,000 troops remain. My guess is that the plan is to keep a 50,000-strong occupation force there indefinitely (or more accurately, until the oil dries up).
The Army Times reported on Saturday that the US still has seven combat brigades inside Iraq, but they have been renamed "advise and assist brigades." The name change will reportedly change little in terms of the duties the brigades carry out: The Army selected the brigade combat teams as the unit upon which to build advisory brigades partly because they would be able to retain their inherent capability to conduct offensive and defensive operations, according to the Army’s security force assistance field manual, which came out in May 2009. This way, the brigade can shift the bulk of its operational focus from security force assistance to combat operations if necessary. Of the roughly 50,000 American military personnel who remain in Iraq, the majority are still combat troops -- they're just named something else. The major units still in Iraq will no longer be called "brigade combat teams" and instead will be called "advisory and assistance brigades." But a rose by any other name is still a rose, and the differences in brigade structure and personnel are minimal.