Harry S. Truman - Threatening Japan With Further Atomic Attacks

 "The world will note that the first atomic bomb was dropped on Hiroshima, a military base.  We run the race of discovery against the Germans.  We have used it in order to shorten the agony of war; in order to save the lives of thousands and thousands of young Americans.  We shall continue to use it until we completely destroy Japan’s power to make war."

"The atomic bombings of Hiroshima and Nagasaki were nuclear attacks during World War II against the Empire of Japan by the United States of America under US President Harry S. Truman. On August 6, 1945, the nuclear weapon "Little Boy" was dropped on the city of Hiroshima, followed on August 9, 1945 by the detonation of the "Fat Man" nuclear bomb over Nagasaki. They were the only instances of the use of nuclear weapons in warfare."

Source: http://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_and_Nagasaki