Explain the rationale behind the United States' use of an atomic bomb.

The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki in August 1945, killing 210,000 people—children, women, and men. President Truman authorized the use of the atom bombs in an effort to bring about Japan's surrender in the Second World War. The main reason given for America's decision to take atomic action is that it was a way to conclude the war without suffering further losses (on the American side at least). There are also those who see the attacks as retribution for Pearl Harbour and the many American lives lost in bloody warfare with Japan. As a signal of American military might, the atomic attacks on Japan were undoubtedly emphatic, especially at a time when the Soviet Union lagged behind the US in the race for nuclear armament.