“No one can be certain of Oppenheimer’s reaction had he learned that on the eve of the Hiroshima bombing, the president knew the Japanese were “looking for peace,” and that the military use of atomic bombs on cities was an option rather than a necessity for ending the war in August. But we do know that after the war he came to believe that he had been misled, and that this knowledge served as a constant reminder that it was henceforth his obligation to be skeptical of what he was told by government officials.”