Iraq wanted all American troops out of the country by the end last year, but they didn't want to lose the use of U.S. troops for training and advising their combat commanders. So the U.S. did what is has increasingly been doing with countries wanting American military training; it brought in contract personnel. There are 157 American military officers assigned to the American embassy in Iraq (and are technically diplomatic personnel), but most of the training assistance and advising is done by 600 retired American military officers and NCOs.
Iraq lives in a dangerous neighborhood. We're the last people they should worry about staying too long or doing harm to them.
UPDATE: Iran does have an edge over Iraq, as weakened as Iran is after decades of sanctions.
