washington top adviser middle east issue u.s. president donald trump leave national security council thursday white house grapple internal divisions well major policy issue involve syria iran iraq weekly standard magazine first report departure derek harvey retire army colonel intelligence officer serve iraq afghanistan magazine say harvey fire michael anton spokesman nsc director h.r mcmaster confirm harvey departure general mcmaster greatly appreciate derek harvey service country career army officer serve country bravely field play crucial role successful surge iraq also service capitol hill trump administration anton say administration work colonel harvey identify position background expertise best utilize anton say statement provide detail separate statement harvey say leave nsc take advantage new opportunity continue serve trump indicate offer particular post harvey praise top administration officials nsc staffers work add look forward shoulder great responsibilities support president middle east adviser depart trump 's national security council