Japan knew the United States was economically and military powerful, but it was not afraid of any American attack on its islands. Japan did worry however, that the Americans might help the Chinese resist the Japanese invasion of their country. When President Roosevelt stopped U.S. shipments of steel and oil the Japan, he was doing exactly this: the Japanese are dependent on other countries for raw materials, for they have almost none on their own islands. Without imports of steel and oil, the Japanese military could not fight for long. Without oil, the navy would not be able to move after it had exhausted its six-month reserve. Roosevelt hoped that this economic pressure would force Japan to end its military expansion in East Asia.
