The anticipated need for commando-type units had not materialized, and the development of the amphibious tractor and improved fire support had ended the need for light assault units. The Raiders had generally performed the same missions as line infantry battalions, either wasting their training and skills, or exposing the lightly armed Raiders to excessive casualties. There was also institutional opposition to the existence of an elite force within the Corps. Two senior officers who had been opposed to the Raiders on this basis advanced to positions where they could abolish the units. On 1 January 1944, Gen. Alexander Vandegrift became Commandant of the Marine Corps, and Gen. Gerald C. Thomas became the Director of Plans and Policies.