Albert Einstein came to regret his warning to President Roosevelt in August 1939. The Germans had split the atom, he wrote, and the Nazis could try to create nuclear weapons. Roosevelt quickly mobilised America’s elite universities and authorised the Manhattan project. (Einstein, ironically, was not among the experts included because he was regarded as a left-wing security risk.) The bomb was built and six years almost to the day from Einstein’s warning, President Truman gave the detonation order.
Einstein’s letter had triggered a chain reaction in the US government that led to Hiroshima, Nagasaki and the Cold War arms race. After the war, Einstein told Newsweek: “Had I known that the Germans would not succeed in developing an atomic bomb, I would have done nothing.”
