The Scientists Who Regretted It

Many Manhattan Project scientists were horrified by the bomb's use. Robert Oppenheimer famously quoted Hindu scripture: "Now I am become Death, the destroyer of worlds." Leo Szilard circulated a petition urging Truman not to use the bomb on civilians.

Oppenheimer campaigned against hydrogen bomb development and lost his security clearance in a controversial 1954 hearing. Leo Szilard, who first conceived the nuclear chain reaction, spent his final years advocating arms control.