When it was discovered that Nazi Germany had the means to build an atomic bomb, Lawrence threw all his energy into waking up the American government to act. Ten years later, when Joseph Stalin's Soviet Union became a nuclear power, Lawrence drove his students to take on the challenge to deter a Communist despot's military ambitions. Their journey was not easy: they had to overcome ridicule over three successive failures, which led to calls to see them, and their laboratory, shut down. At the Nobska Conference in 1956, the Rad Lab physicists took up the daunting challenge to provide the Navy with a warhead for Polaris.
The success of the Polaris missile, which could be carried by submarines, was a critical step in establishing nuclear deterrent capability and helped Kennedy stare down Khrushchev during the Berlin Crisis of 1961. Six months after the height of that crisis, Kennedy thought about how close the country had come to destruction, and he flew out to Berkeley to meet and thank a small group of Rad Lab physicists for helping the country avert a nuclear war.