Why did the Truman Administration decide to drop the atomic bombs on Japan in 1945?

There has been much debate as to why Truman elected to drop the atomic weapons on Hiroshima and Nagasaki in the summer of 1945. Historians have long debated the true purpose to which the atomic bombs were designed to fulfil upon there deployment. The Alperovitz thesis of the 1960 was accepted for many years. The thesis revolved around the idea that the atomic weapons were deployed as diplomatic tools to intimidate the Soviet Union. Like many revisionist historians this essay will oppose the thesis of Alperovitz, and in doing so, attempt to understand why it was that the Truman administration decided to drop the atomic weapons on Japan in the summer of
It has been argued that the Truman administration deliberately did not change the surrender clauses in order to draw out the war with Japan, effectively buying time for the atomic bombs to be successfully tested and deployed. This would suggest strongly that the atomic bombs were dropped as a tool to demonstrate America's diplomatic dominance to the world and not primarily to save American lives. However, Truman’s actions can be justified as according to Marshall 'Joseph Grew, the acting Secretary of State and former US Ambassador to Japan, told Truman that peace was being blocked by the doctrine of unconditional surrender'.[9] Marshall goes on to state that 'Truman had no objection to altering the terms of surrender; he rejected Grew’s suggestion partly for domestic reasons.'[10] This suggests that Truman was well aware that the quickest way to end the conflict was to change the conditions of the Japanese surrender. We can speculate that the domestic reasons Truman is hereby referring to is the pressure he was receiving from the public to see Japan annihilated in retaliation for the Japanese actions at Pearl Harbour. "Having found the bomb we have used it. We have used it against those who attacked us without warning at Pearl Harbour.”[11] Therefore, although Truman theoretically could have ended the war sooner, he did. It could be suggested that he did this for two reasons. Firstly because of the