he had maintained a consistent thought process regarding it and that once his questions about the utility of the weapon had been resolved, his conclusion about the question changed accordingly. In 1953 Smyth and John A. Hall served as principal advisors to President Dwight Eisenhower in preparing his Atoms for Peace speech to the United Nations. The IAEA traces its origins to this speech. The 1954 Oppenheimer security hearing consisted of a panel considering whether to rescind Oppenheimer's security clearance on suspicion that he was disloyal or a security risk, with the result that the panel decided to do so. Smyth was still the only scientist on the commission. Despite his personal dislike of Oppenheimer and pressure from the commission's new chairman, Lewis Strauss, in confirmation of the panel's decision Smyth was the sole commissioner to vote against stripping Oppenheimer's clearance on June 29, 1954. Smyth's rationale for what McGeorge Bundy has called his "lonely but powerful dissent" was that the evidence against Oppenheimer was weak and even contrived and was easily outweighed by Oppenheimer's contributions to U.S. nuclear weapons efforts. Smyth resigned from the AEC on September 30 of that year out of frustration with Strauss. Eulogizing Oppenheimer in 1967, Smyth said of Oppenheimer's treatment, "Such a wrong can never be righted; such a blot on our history never erased.... We regret that his great work for his country was repaid so shabbily". Smyth returned to Princeton and served on several high-level administrative committees. This work included advising on the construction of a particle accelerator built jointly with the University of Pennsylvania and overseeing Project Matterhorn, which became the Princeton Plasma Physics Laboratory. He chaired the committee that chose Robert F. Goheen to succeed Harold W. Dodds as President of Princeton. He also served as a consultant on nuclear power to Congress, the AEC, and private industry. He retired from Princeton in 1966. Smyth was a fellow of the American Physical Society and served as its vice president in 1956 and its president in 1957. He was elected to the American Philosophical Society in 1947 and the American Academy of Arts and Sciences in 1956. He was a member of the Council on Foreign Relations. IAEA representative President John F. Kennedy appointed Smyth as the representative of the United States to the IAEA, a position with the rank of Ambassador. Smyth assumed the position on June 13, 1961, following