If not Oppenheimer in the U.S., then who? A German? Japanese? Italian? Russian? The U.S. deployed two atomic bombs at a time when no one knew what the long term radioactive effects might be. No justification was necessary, no remorse called for. The U.S. has demonstrated the responsible use of the weapon, and has not deployed any further. Does anyone believe that any of the Axis powers or Russia would have stopped deployment of nuclear weapons after winning WW2 if they had it first? Surely the Empire of Japan would have used nuclear weapons against China if they had them. The Third Reich would surely have deployed nukes against the Soviet Union, and likely against the U.S. Mussolini would have used them in North Africa. Stalin would not be stopped as he was by the U.S. Oppenheimer gets the credit/blame but whoever was put in that position would have had the same result. Someone was going to do it.