J. Robert Oppenheimer (April 22, 1904 – February 18, 1967) was an American theoretical physicist, best known for his role as the scientific director of the Manhattan Project, the World War II effort to develop the first nuclear weapons, at the secret Los Alamos laboratory in New Mexico. Known colloquially as "the father of the atomic bomb", Oppenheimer lamented the weapon's killing power after it was used to destroy the Japanese cities of Hiroshima and Nagasaki. After the war, he was a chief advisor to the newly created Atomic Energy Commission and used that position to lobby for international control of atomic energy and to avert the nuclear arms race with the Soviet Union. After invoking the ire of many politicians and scientists with his outspoken political opinions during the Red Scare, he had his security clearance revoked in a much-publicized and politicized hearing in 1954. Though stripped of his direct political influence, Oppenheimer continued to lecture, write, and work in physics. A decade later, President John F. Kennedy awarded him the Enrico Fermi Award as a gesture of reconciliation. As a scientist, Oppenheimer is remembered most for being a chief founder of the American school of theoretical physics while at the University of California, Berkeley.