The Maine National Guard’s No. 2 commander is hanging up his uniform. Brig. Gen. Donald McCormack is stepping down as Maine’s Assistant Adjutant General, Air. His retirement marks the end of a 32-year military career that began after his 1980 graduation from the Air Force Academy. McCormack came to Maine in 1991 and has served as the state’s assistant adjutant general since April 2011. He’s being replaced by Col. John Derrico, who is commander of the 101st Air Refueling Wing.