September 1, 1939. World War II in Europe erupted. America was not prepared for war. The Army, which included the Air Corps, numbered only 188,000 Regular Army soldiers, 200,000 National Guardsmen, and 139,000 Reservists. Its strength was rated nineteenth in the world, just behind Romania. Twenty-six percent of the Army served overseas. It was an army designed for colonial policing, border patrols, and coastal defense.
The Army had only 329 obsolete light tanks and approximately 1,800, mostly obsolete, aircraft. Harbor defenses were of Spanish-American War era design and lacked overhead protection from aerial attack. Soldiers were supplied mostly with World War I weapons and equipment. Despite a building and modernization program that started in the mid-1930s, a large portion of the Navy, including all of its battleships, dated to World War I. Shipyards took over a year to build a destroyer and several years to build larger ships.