It ' s because the Russians were getting closer and closer to Japan . The other allied countries didn ' t want this . The Japanese were not going to surrender . We destroyed something like 65 Percent of their cities using firebombing , and they still wouldn ' t surrender . There was almost a military coup against the emperor but it was put down . The USA didnt have the luxury of time . The Russians had already taken much of what Japan had gained in China and where hungry for more . After all , the Soviets wanted to spread communism all over the world . Nobody wanted Soviet communism . Nobody . The Americans used the bombs to close the Pacific theatre . This allowed them to shut out the russians so that they would have no excuse to advance further . It was also a demonstration of power intended to show the russians that they were not to be toyed with .