What rank was the us military when world war 2 started?

General George C. Marshall was sworn in as the Army's new commander on September 3, 1939, two days after Nazi tanks rolled into Poland, the generally recognized beginning of the war. When Marshall became Chief of Staff he inherited an army that was the twenty-first largest in the world (right behind Bulgaria) and was primed, but not prepared, to refight World War One. Six years later the US had an army of eight million and had defeated all its foes. Marshall also commanded the Air Force, which remained a part of the army until 1947, so he had an additional three million men under his command in the air service. Marshall was the true architect of victory. Marshall always intended to go to Europe and command in person when the invasion of France took place, but President Roosevelt said he would not be able to sleep at night if Marshall was away from Washington. So, the command and the fame that came with it went to Marshall's protege, Eisenhower. Marshall retired in late 1945, but got to rest only six days before the President called and asked Marshall to undertake a diplomatic mission to China. Marshall eventually became Secretary of State and is perhaps best remembered for the "Marshall Plan", which helped get Europe back on its feet, and forestalled the recriminations which followed the first war and led directly to the second. A truly great American.