In 1940, as World War II raged overseas, Romney helped start the Automotive Committee for Air Defense, which coordinated planning between the automobile and aircraft industries. Immediately following the December 1941 attack on Pearl Harbor that drew the U.S. into the war, Romney helped turn that committee into, and became managing director of, the Automotive Council for War Production. This organization established a cooperative arrangement in which companies could share machine tools and production improvements, thus maximizing the industry's contribution to the war production effort. It embodied Romney's notion of "competitive cooperative capitalism".