A further argument , discussed under the rubric of " atomic diplomacy " and advanced in a 1965 book of that name by Gar Alperovitz , is that the bombings had as primary purpose to intimidate the Soviet Union , being the opening shots of the Cold War . Along these lines some argue that the United States raced the Soviet Union and hoped to drop the bombs and receive surrender from Japan before a Soviet entry into the Pacific War . However , the Soviet Union , the United States , and the United Kingdom came to an agreement at the Yalta Conference on when the Soviet Union should join the war against Japan , and on how the territory of Japan was to be divided at the end of the war
Yalta Conference
Yalta Conference
Debate over the atomic bombings of Hiroshima and Nagasaki