The United States was attacked by Japan on December 7, 1941, at Pearl Harbor. On that same day, The United States entered World War II. Fierce fighting with the Japanese left a large number of American soldiers dead or wounded. The United States had been working on building an atomic bomb, hoping to have one built before Germany was capable of using one on the Allies. Harry S. Truman, the 33rd President of the United States, had to make one the most difficult military decisions in history. He had to choose whether or not to use the atomic bomb on Japan. He was hoping the bomb would end World War II with Japan. There are a number of reasons why Truman chose to drop the atomic bomb. The United States targeted three cities, but Hiroshima
