Today is the 74th Anniversary of the first nuclear detonation–at Alamogordo NM. The result of the nearly 3 years and $2.5 Billion Manhattan Project, it influenced American decision makers at Potsdam. Secretary of War Stimson wrote in his diary on July 22, 1945. “…Now I know what happened to Truman yesterday. I couldn’t understand it. When he got to the meeting after having read this report (re Alamagordo test results) he was a changed man. He told the Russians just where they got on and off and generally bossed the whole meeting.” Churchill said he now understood how this pepping up had taken place and that he felt the same way. His own attitude confirmed this admission. -quoted in Alperowitz, “The Decision to Drop the Bomb”, pg. 249.
Alperowitz outlines his assessment of the impact of Alamogordo on US policy in Europe: “Not only did American officials “distance themselves from the position on reparations taken by Roosevelt at Yalta, “they also thereby almost certainly committed what the Russians saw as an “overt violation of the meaning and spirit of the Yalta compromises.” Indeed although Red Army help to control Germany had once seemed absolutely essential, the United States now became quite cavalier in its negotiations. The United States also was now more than willing to accept a far more powerful industrial basis for the German economy than had previously been assumed. Moreover, once again U.S. leaders were quite willing to leave Potsdam with no agreement — and to await the development of events. Nor is there any doubt about what produced this evolution. At Potsdam, UK.S. leaders explicitly stated their private judgment that the atomic bomb had given them power to control all security problems — including the once-central German threat. (ibid p. 281)