This summer’s release of Oppenheimer, the major Hollywood movie by Christopher Nolan, has brought renewed attention to J. Robert Oppenheimer’s thoughts, concerns, and intentions regarding the U.S. pursuit of thermonuclear weapons. This paper provides context surrounding the 1949 recommendation of the Atomic Energy Commission’s General Advisory Committee, chaired by Oppenheimer, against a crash program for hydrogen bombs, a recommendation that would be used against him in the 1954 decision to revoke his security clearance. An appendix reproduces the April 5, 2022, letter from Los Alamos National Laboratory directors to the secretary of energy. In December 2022, Secretary of Energy Granholm vacated the original security review board decision.