In May 1945 , Conant became part of the Interim Committee that was formed to advise the new president , Harry S. Truman on nuclear weapons . The Interim Committee decided that the atomic bomb should be used against an industrial target in Japan as soon as possible and without warning . On July 16 , 1945 , Conant was among the dignitaries present at the Alamogordo Bombing and Gunnery Range for the Trinity nuclear test , the first detonation of an atomic bomb . After the war , Conant became concerned about growing criticism in the United States of the bombing of Hiroshima and Nagasaki by figures like Norman Cousins and Reinhold Niebuhr . He played an important behind-the-scenes role in shaping public opinion by instigating and then editing an influential February 1947 '' Harper 's '' article entitled " The Decision to Use the Atomic Bomb " . Written by former Secretary of War Henry L. Stimson with the help of McGeorge Bundy , the article stressed that the atomic bombings of Hiroshima and Nagasaki were used to avoid the possibility of " over a million casualties " , from a figure found in the estimates given to the Joint Chiefs of Staff by its Joint Planning Staff in 1945
Trinity nuclear test
Trinity (nuclear test)
James B. Conant