 General Lesley J. McNair was head of the Army Ground Forces from 1942 to 1944.McNair, a former artilleryman, advocated for the role of the tank destroyer (TD) within the U.S. Army.In McNair's opinion, tanks were to exploit breakthroughs and support infantry, while masses of attacking hostile tanks were to be engaged by tank destroyer units, which were composed of a mix of self-propelled and towed anti-tank guns.