U.S. Marine Corps Aviation was much more prepared for the application of CAS in the Vietnam War, due to CAS being its central mission. One of the main debates taking place within the Marine Corps during the war was whether to adopt the helicopter gunship as a part of CAS doctrine and what its adoption would mean for fixed-wing CAS in the Marine Corps. The issue would eventually be put to rest, however, as the helicopter gunship proved crucial in the combat environment of Vietnam.