Once the public learned of the Manhattan Project after the bombings of Hiroshima and Nagasaki, Oppenheimer—suddenly a household name as the "father of the atomic bomb"—became a national spokesman for science, emblematic of a new type of technocratic power; Nuclear physics became a powerful force as nations realized the strategic and political power that atomic weapons conferred. Like many scientists of his generation, Oppenheimer felt that security from atomic bombs could come only from a transnational organization such as the newly formed
United Nations, which could institute a program to stifle a
nuclear arms race.
Institute for Advanced Study had been colleagues and shared a cordial
relationship with each other. |alt=Einstein writing at a desk. Oppenheimer sits beside him, looking on. In November 1945, Oppenheimer left Los Alamos to return to Caltech, but soon found that his heart was no longer in teaching. In 1947, he accepted an offer from
Lewis Strauss to take up the directorship of the
Institute for Advanced Study in
Princeton, New Jersey. This meant moving back east and leaving
Ruth Tolman, the wife of his friend Richard Tolman, with whom he had begun an affair after leaving Los Alamos. The job came with a salary of $20,000 per annum, plus rent-free accommodation in the director's house, a 17th-century manor with a cook and
groundskeeper, surrounded by of woodlands. He collected European furniture, and French
Post-Impressionist and
Fauvist artworks. His art collection included works by
Cézanne,
Derain,
Despiau,
de Vlaminck, Picasso,
Rembrandt,
Renoir, Van Gogh and Vuillard. Oppenheimer brought together intellectuals at the height of their powers and from a variety of disciplines to answer the most pertinent questions of the age. He directed and encouraged the research of many well-known scientists, including
Freeman Dyson, and the duo of
Chen Ning Yang and
Tsung-Dao Lee, who won a Nobel Prize for their discovery of
parity non-conservation. He also instituted temporary memberships for scholars from the humanities, such as
T. S. Eliot and
George F. Kennan. Some of these activities were resented by a few members of the mathematics faculty, who wanted the institute to stay a bastion of pure scientific research. Abraham Pais said that Oppenheimer himself thought that one of his failures at the institute was being unable to bring together scholars from the natural sciences and the humanities. During a series of conferences in New York—the
Shelter Island Conference in 1947, the
Pocono Conference in 1948, and the
Oldstone Conference in 1949—physicists transitioned from war work back to theoretical issues. Under Oppenheimer's direction, physicists tackled the greatest outstanding problem of the pre-war years: infinite, divergent, and seemingly nonsensical expressions in the quantum electrodynamics of
elementary particles.
Julian Schwinger,
Richard Feynman and
Shin'ichiro Tomonaga tackled the problem of
regularization, and developed techniques that became known as
renormalization. Freeman Dyson was able to prove that their procedures gave similar results. The problem of
meson absorption and
Hideki Yukawa's theory of mesons as the carrier particles of the
strong nuclear force were also tackled. Probing questions from Oppenheimer prompted
Robert Marshak's innovative two-meson
hypothesis: that there are actually two types of mesons,
pions and
muons. This led to
Cecil Frank Powell's breakthrough and subsequent Nobel Prize for the discovery of the pion. Oppenheimer served as director of the institute until 1966, when he gave up the position due to his failing health.
Atomic Energy Commission As a member of the Board of Consultants to a committee appointed by Truman, Oppenheimer strongly influenced the 1946
Acheson–Lilienthal Report. In this report, the committee advocated the creation of an international Atomic Development Authority, which would own all fissionable material and the means of its production, such as mines and laboratories, and atomic power plants where it could be used for peaceful energy production.
Bernard Baruch was appointed to translate this report into a proposal to the United Nations, resulting in the
Baruch Plan of 1946. The Baruch Plan introduced many additional provisions regarding enforcement, in particular requiring inspection of the Soviet Union's uranium resources. It was seen as an attempt to maintain the United States' nuclear monopoly and rejected by the Soviets. With this, it became clear to Oppenheimer that an arms race was unavoidable, due to the mutual suspicion of the United States and the Soviet Union, which even Oppenheimer was starting to distrust. After the Atomic Energy Commission (AEC) came into being in 1947 as a civilian agency in control of nuclear research and weapons issues, Oppenheimer was appointed as the chairman of its General Advisory Committee (GAC). From this position, he advised on a number of nuclear-related issues, including project funding, laboratory construction and even international policy—though the GAC's advice was not always heeded. As chairman of the GAC, Oppenheimer lobbied vigorously for international arms control and funding for basic science, and attempted to influence policy away from a heated arms race. The
first atomic bomb test by the Soviet Union in August 1949 came earlier than Americans expected, and over the next several months, there was an intense debate within the U.S. government, military, and scientific communities over whether to proceed with the development of the far more powerful,
nuclear fusion–based
hydrogen bomb, then known as "the Super". Oppenheimer had been aware of the possibility of a thermonuclear weapon since the days of the Manhattan Project and had allocated a limited amount of theoretical research work toward the possibility at the time, but nothing more than that, given the pressing need to develop a fission weapon. Immediately following the end of the war, Oppenheimer argued against continuing work on the Super at that time, due to both lack of need and the enormous human casualties that would result from its use. Now in October 1949, Oppenheimer and the GAC recommended against the development of the Super. He and the other GAC members were motivated partly by ethical concerns, feeling that such a weapon could only be strategically used, resulting in millions of deaths: "Its use therefore carries much further than the atomic bomb itself the policy of exterminating civilian populations." They also had practical qualms, as there was no workable design for a hydrogen bomb at the time. Regarding the possibility of the Soviet Union developing a thermonuclear weapon, the GAC felt that the United States could have an adequate stockpile of atomic weapons to retaliate against any thermonuclear attack. In that connection, Oppenheimer and the others were concerned about the
opportunity costs that would be incurred if nuclear reactors were diverted from materials needed for atom bomb production to the materials such as
tritium needed for a thermonuclear weapon. A majority of the AEC subsequently endorsed the GAC recommendation, and Oppenheimer thought that the fight against the Super would triumph, but proponents of the weapon lobbied the White House vigorously. On January 31, 1950, Truman, who was predisposed to proceed with the development of the weapon anyway, made the formal decision to do so. Oppenheimer and other GAC opponents of the project, especially
James B. Conant, felt disheartened and considered resigning from the committee. They stayed on, though their views on the hydrogen bomb were well known. In 1951, Teller and mathematician
Stanislaw Ulam developed the
Teller–Ulam design for a hydrogen bomb. This new design seemed technically feasible and Oppenheimer officially acceded to the weapon's development, while still looking for ways in which its testing or deployment or use could be questioned. As he later recalled: Oppenheimer, Conant, and
Lee DuBridge, another member who had opposed the H-bomb decision, left the GAC when their terms expired in August 1952. Truman had declined to reappoint them, as he wanted new voices on the committee who were more in support of H-bomb development. In addition, various opponents of Oppenheimer had communicated to Truman their desire that Oppenheimer leave the committee.
Panels and study groups colloquium on the
Super. In the front row are
Norris Bradbury,
John Manley,
Enrico Fermi and J. M. B. Kellogg. Behind Manley is Oppenheimer (wearing jacket and tie), and to his left is
Richard Feynman. The Army colonel on the far left is
Oliver Haywood. In the third row between Haywood and Oppenheimer is
Edward Teller.|alt=A group of formally dressed people sit in the audience, on folding chairs, and listen to a lecture Oppenheimer played a role on a number of government panels and study projects during the late 1940s and early 1950s, some of which thrust him into controversies and power struggles. In 1948, Oppenheimer chaired the Department of Defense's Long-Range Objectives Panel, a body created by AEC liaison
Donald F. Carpenter. It looked at the military utility of nuclear weapons, including how they might be delivered. After a year's worth of study, in spring 1952, Oppenheimer wrote the draft report of
Project GABRIEL, which examined the dangers of
nuclear fallout. Oppenheimer was also a member of the Science Advisory Committee of the
Office of Defense Mobilization. Oppenheimer participated in
Project Charles during 1951, which examined the possibility of creating an effective air defense of the United States against atomic attack, and in the follow-on Project East River in 1952, which, with Oppenheimer's input, recommended building a warning system that would provide one-hour notice of an impending atomic attack against American cities. Oppenheimer's and other scientists' urging that resources be allocated to air defense in preference to large retaliatory strike capabilities brought an immediate response of objection from the
United States Air Force (USAF), and debate ensued about whether Oppenheimer and allied scientists, or the Air Force, was embracing an inflexible "
Maginot Line" philosophy. In any case, the Summer Study Group's work eventually led to the building of the
Distant Early Warning Line. Teller, who had been so uninterested in work on the atomic bomb at Los Alamos during the war that Oppenheimer had given him time instead to work on his own project of the hydrogen bomb, left Los Alamos in 1951 to help found, in 1952, a second laboratory at what would become the
Lawrence Livermore National Laboratory. Oppenheimer had defended the history of work done at Los Alamos and opposed the creation of the second laboratory.
Project Vista looked at improving U.S. tactical warfare capabilities. Strategic thermonuclear weapons delivered by long-range jet bombers would necessarily be under the control of the U.S. Air Force, whereas the Vista conclusions recommended an increased role for the U.S. Army and U.S. Navy as well. The Air Force reaction to this was immediately hostile, and it succeeded in getting the Vista report suppressed. During 1952, Oppenheimer chaired the five-member
State Department Panel of Consultants on Disarmament, which first urged that the United States postpone its planned first test of the hydrogen bomb and seek a thermonuclear test ban with the Soviet Union, on the grounds that avoiding a test might forestall the development of a catastrophic new weapon and open the way for new arms agreements between the two nations. But the panel lacked political allies in Washington, and the
Ivy Mike shot went ahead as scheduled. One of the panel's recommendations, which Oppenheimer felt was especially important, was that the U.S. government practice less secrecy and more openness toward the American people about the realities of the nuclear balance and the dangers of nuclear warfare. Oppenheimer subsequently presented his view on the lack of utility of ever-larger nuclear arsenals to the American public in a June 1953 article in
Foreign Affairs, and it received attention in major American newspapers. Thus by 1953, Oppenheimer had reached another peak of influence, being involved in multiple different government posts and projects and having access to crucial strategic plans and force levels. This view was paired with their fear that Oppenheimer's fame and powers of persuasion had made him dangerously influential in government, military, and scientific circles.
Security hearing receives a report from
Lewis L. Strauss, Chairman of the
Atomic Energy Commission, on the
Operation Castle hydrogen bomb tests in the Pacific, March 30, 1954. Strauss pressed for Oppenheimer's security clearance to be revoked.|alt=They sit in the Oval Office and have a discussion The FBI under
J. Edgar Hoover had been following Oppenheimer since before the war, when he showed Communist sympathies as a professor at Berkeley and had been close to members of the Communist Party, including his wife and brother. They strongly suspected that he himself was a member of the party, based on wiretaps in which party members referred to him or appeared to refer to him as a communist, as well as reports from informers within the party. He had been under close surveillance since the early 1940s, his home and office bugged, his phone tapped and his mail opened. In August 1943, Oppenheimer told Manhattan Project security agents that
George Eltenton, whom he did not know, had solicited three men at Los Alamos for nuclear secrets on behalf of the
Soviet Union. When pressed on the issue in later interviews, Oppenheimer admitted that the only person who had approached him was his friend
Haakon Chevalier, a Berkeley professor of French literature, who had mentioned the matter privately at a dinner at Oppenheimer's house. The FBI furnished Oppenheimer's political enemies with evidence that intimated communist ties. These enemies included Strauss, an AEC commissioner who had long harbored resentment against Oppenheimer both for his activity in opposing the hydrogen bomb and for his humiliation of Strauss before Congress some years earlier. Strauss had expressed opposition to exporting radioactive isotopes to other nations, and Oppenheimer had called them "less important than electronic devices but more important than, let us say, vitamins." On June 7, 1949, Oppenheimer testified before the
House Un-American Activities Committee that he had associations with the Communist Party USA in the 1930s. He testified that some of his students, including
David Bohm,
Giovanni Rossi Lomanitz,
Philip Morrison,
Bernard Peters, and
Joseph Weinberg had been communists at the time they had worked with him at Berkeley. Frank Oppenheimer and his wife Jackie testified before HUAC that they had been members of the Communist Party USA. Frank was subsequently fired from his
University of Minnesota position. Unable to find work in physics for many years, he became a
cattle rancher in
Colorado. He later taught high school physics and was the founder of the San Francisco
Exploratorium. The triggering event for the security hearing happened on November 7, 1953, when
William Liscum Borden, who until earlier in the year had been the executive director of the
United States Congress Joint Committee on Atomic Energy, sent Hoover a letter saying that "more probably than not J. Robert Oppenheimer is an agent of the Soviet Union." Eisenhower never exactly believed the allegations in the letter but felt compelled to move forward with an investigation, and on December 3, he ordered that a "blank wall" be placed between Oppenheimer and any government or military secrets. On December 21, 1953, Strauss told Oppenheimer that his security clearance had been suspended, pending resolution of a series of charges outlined in a letter, and discussed his resigning by way of requesting termination of his consulting contract with the AEC. Oppenheimer chose not to resign and requested a hearing instead. The charges were outlined in a letter from
Kenneth D. Nichols, general manager of the AEC. Nichols, who had thought highly of Oppenheimer's work on the earlier Long-Range Objectives Panel, He nonetheless drafted the letter, but later wrote that he was "not happy with the inclusion of a reference concerning Oppenheimer's opposition to the hydrogen bomb development." The hearing that followed in April–May 1954, which was held in secret, focused on Oppenheimer's past communist ties and his association during the Manhattan Project with suspected disloyal or communist scientists. It then continued with an examination of Oppenheimer's opposition to the H-bomb and stances in subsequent projects and study groups. A transcript of the hearings was published in June 1954, with some redactions. In 2014, the U.S.
Department of Energy made the full transcript public. , testified against Oppenheimer at his security hearing in 1954. |alt=Head and shoulders portrait. One of the key elements in this hearing was Oppenheimer's earliest testimony about George Eltenton's approach to various Los Alamos scientists, a story that Oppenheimer confessed he had fabricated to protect his friend
Haakon Chevalier. Unknown to Oppenheimer, both versions were recorded during his interrogations of a decade before. He was surprised on the witness stand with transcripts of these, which he had not been given a chance to review. In fact, Oppenheimer had never told Chevalier that he had finally named him, and the testimony had cost Chevalier his job. Both Chevalier and Eltenton confirmed mentioning that they had a way to get information to the Soviets, Eltenton admitting he said this to Chevalier and Chevalier admitting he mentioned it to Oppenheimer, but both put the matter in terms of gossip and denied any thought or suggestion of treason or thoughts of espionage, either in planning or in deed. Neither was ever convicted of any crime. Teller testified that he considered Oppenheimer loyal to the U.S. government, but that: Teller's testimony outraged the scientific community, and he was virtually ostracized from academic science. Ernest Lawrence refused to testify, pleading an attack of ulcerative colitis, but an interview in which Lawrence condemned Oppenheimer was submitted in evidence. Many top scientists, as well as government and military figures, testified on Oppenheimer's behalf. Physicist
Isidor Isaac Rabi said that the suspension of the security clearance was unnecessary: "he is a consultant, and if you don't want to consult the guy, you don't consult him, period." But Groves testified that, under the stricter security criteria in effect in 1954, he "would not clear Dr. Oppenheimer today". At the conclusion of the hearings, the board revoked Oppenheimer's clearance by a 2–1 vote. It unanimously cleared him of disloyalty, but a majority found that 20 of the 24 charges were either true or substantially true and that Oppenheimer would represent a security risk. Then on June 29, 1954, the AEC upheld the findings of the Personnel Security Board, by a 4–1 decision, with Strauss writing the majority opinion. In that opinion, he stressed Oppenheimer's "defects of character", "falsehoods, evasions and misrepresentations", and past associations with Communists and people close to Communists as the primary reasons for his determination. He did not comment on Oppenheimer's loyalty. During his hearing, Oppenheimer testified on the left-wing activities of ten of his colleagues and previous acquaintances, mostly in reference to activities in the late 1930s. These ten people's activities were already public knowledge through prior hearings and activities (such as Addis, Chevelier, Lambert, May, Pitman, and I. Folkoff) or already known to the FBI. Some believe that had his clearance not been stripped, he might have been remembered as someone who "named names" to save his own reputation, but as it happened, most in the scientific community saw him as a martyr to
McCarthyism, an eclectic liberal unjustly attacked by warmongering enemies, symbolic of the shift of scientific work from academia into the military.
Wernher von Braun told a Congressional committee: "In England, Oppenheimer would have been knighted." In a seminar at
The Wilson Center in 2009, based on an extensive analysis of the
Vassiliev notebooks taken from the KGB archives,
John Earl Haynes,
Harvey Klehr and
Alexander Vassiliev confirmed that Oppenheimer never was involved in espionage for the Soviet Union, though Soviet intelligence tried repeatedly to recruit him. Further, he had several persons removed from the Manhattan Project who had sympathies to the Soviet Union. For their part, Jerrold and Leona Schecter conclude that based on
The Merkulov Letter, Oppenheimer must have been only a "facilitator", not a spy in the strict sense (although he would fall under that
legal category in the U.S.). On December 16, 2022,
United States Secretary of Energy Jennifer Granholm vacated the 1954 revocation of Oppenheimer's security clearance. Her statement said, "In 1954, the Atomic Energy Commission revoked Dr. Oppenheimer's security clearance through a flawed process that violated the Commission's own regulations. As time has passed, more evidence has come to light of the bias and unfairness of the process that Dr. Oppenheimer was subjected to while the evidence of his loyalty and love of country have only been further affirmed." Granholm's decision has drawn criticism. == Final years ==