Which of these brought a final end to world war ii? the united states' use of atomic weapons

Truman’s intent to use the bomb as an alternative to negotiating with Stalin was evident as soon as the bomb was completed. Truman refused to tell Stalin about the bomb, despite the fact that the two were wartime allies. Instead, upon successful testing of the device, Truman mentioned to Stalin that he had “a weapon of unusual destructive force.” Truman was purposely secretive to insure that it would be a shock to the Russians as well as the Japanese. In Truman’s mind, had a Russian declaration of war against Japan forced a surrender, rather than the bomb, Stalin might demand a larger role in the Japanese peace negotiations. Truman refused to let Stalin put him in such a disadvantageous position.

b) that he was not a free man