 When World War II broke out in Europe, Devers was stationed in Panama. He was promoted to major general in October 1940 and took command of the newly formed 9th Infantry Division at Fort Bragg, North Carolina, a base whose construction he oversaw. Appointed Chief of the Armored Force in August 1941, he supervised its expansion from four armored divisions to sixteen. He was an articulate proponent of the emerging tactical doctrine of combined arms, and rejected the American doctrine that held that tanks were for exploitation, not for fighting other tanks. He pressed American industry to produce more powerful engines, and, often against the views of his superiors, pushed the development of the M4 Sherman, a medium tank with a 75mm gun. Not satisfied with the Sherman, he called for still more heavily armed and armored tanks. He wanted 250 of the new M26 Pershing tanks for Operation Overlord, but was overruled.
