http://www.fff.org/freedom/1195f.asp In his memoirs after the war, President Truman said that an invasion of the Japanese home islands would have cost the lives of upwards of half a million American soldiers. The likelihood of such high American casualties, he argued, was the primary reason why he decided to use the atomic bomb to end the war quickly. In fact, Professor Skates tells us, no such number had ever been suggested in any of the planning estimates before the invasion of Kyushu. The estimate most generally accepted was that in the first sixty days of the assault on Kyushu, American casualties would be between 55,000 and 78,000, with the dead numbering between 14,000 and 20,000. These numbers would have been approximately equal to the losses suffered in the invasion of Luzon in the Philippines. This estimate had been given to President Truman at a meeting with the Joint Chiefs on June 18, 1945; he seemed satisfied, telling them to proceed with the plans for Operation Olympic ........ Eight months after the end of the war, U.S. intelligence officers on the army general staff undertook a "what if" study of an invasion of Japan. "They concluded," Professor Skates tells us, "that the failure of these [Japanese peace] efforts [through their embassy in Moscow] and the sudden Soviet declaration of war on 9 August would have been sufficient, even without the atomic bombs, to end the war. However, in the unlikely event that the Japanese continued in the war after the entry of the USSR, and OLYMPIC had been launched, 'The island of Kyushu would have been occupied in not over two months at a cost of 75,000 to 100,000 casualties.' In that case, concluded the analysts, the war would have ended no later than 15 February, 1946, and Coronet would not have been necessary.