Nevertheless, until July 1945, the atomic bomb remained untested and the leading plan of the U.S. was to invade Japan through Operation Downfall, beginning with an invasion of the southernmost island of Kyushu in October 1945. In terms of the operation, there were numerous  estimates as to the potential U.S. casualties. President Truman received estimates from General MacArthur that upwards of 31,000  U.S. casualties could be expected within the first thirty days. However, other estimates, particularly by the Joint Chiefs, projected casualties to reach almost seven times higher. This is a far cry from the estimate of millions of casualties which has been bandied about in the contemporary media. Nevertheless, Operation Downfall posed a definitive risk to U.S. soldiers.
At the same time, alternatives to both the bomb and the invasion were discussed by the Interim Committee established to advise the manner in which nuclear weapons  should be employed against Japan. During these meetings, the Committee discussed three specific alternatives: