Murphy plays Oppenheimer, who was a theoretical physicist that was recruited to work on the Manhattan Project in 1942 during World War II. He eventually became the director of the Los Alamos Laboratory in New Mexico, which is where the first atomic bombs were developed. His ties to the Communist Party and views against the creation of the hydrogen bomb resulted in him getting his security clearance taken away in 1954. This ended his partnership with the United States government and led him to lose political power.
Image Source: Everett Collection; Getty/ Corbis Historical