The 1949 House Un-American Activities Committee investigation of the Berkeley Radiation Laboratory brought the political histories of J. Robert Oppenheimer’s former students into a congressional inquiry into atomic espionage. A wiretapped conversation, political associations, and the committee’s pursuit of testimony made the investigation more than a search for evidence: it became a test of whether scientists could protect their colleagues without making themselves vulnerable to suspicion. The proceedings reached Oppenheimer as well, exposing the strain between his former students’ predicament and his own need to avoid political danger.

Background and targets

In the spring of 1949, the House Un-American Activities Committee opened a major investigation of alleged atomic spying at Berkeley’s Radiation Laboratory. Four of Oppenheimer’s former students—David Bohm, Giovanni Rossi Lomanitz, Max Friedman, and Joseph Weinberg—received subpoenas requiring them to testify. The committee had heard Weinberg on a wiretap speaking with Steve Nelson in 1943 about the atomic bomb. That conversation appeared to implicate Weinberg, but the committee’s counsel understood that a warrantless wiretap would not stand up in court. The investigators therefore sought testimony from people who might substantiate their case without relying on evidence difficult to use in a prosecution.

The inquiry unfolded against a broader climate of surveillance and suspicion. In 1946, FBI chief J. Edgar Hoover had investigated numerous senior Truman Administration officials associated with atomic-energy policy, including people whose positions were not identical to Oppenheimer’s. The book presents those investigations as a prelude to a politics in which accusations of communist sympathies could be used to silence or damage political opponents. As concern about protecting atomic secrets grew, political associations and disagreements over nuclear policy could be treated as signs of possible disloyalty. The Berkeley investigation brought that wider suspicion to bear on the careers and choices of individual scientists.

Confrontation and testimony

On April 26, 1949, the committee brought Weinberg face-to-face with Nelson. Weinberg flatly denied ever having met him. The committee’s lawyers believed Weinberg had committed perjury, but proving it was another matter: the wiretap that prompted their suspicion could not readily serve as admissible proof. The investigators hoped to build their case instead through testimony from Bohm, Friedman, and Lomanitz. The confrontation thus revealed the gap between what the committee suspected and what it could establish by evidence it could use.

Bohm was uncertain whether to testify and whether doing so would require him to speak about friends. Albert Einstein urged him to refuse, even if refusal meant going to jail. Bohm reasoned that membership in the Communist Party was not illegal; his instinct was to discuss his own political activity but decline to testify about others. Knowing that Lomanitz had received a similar subpoena, Bohm contacted him in Nashville, where Lomanitz was teaching. Lomanitz had repeatedly lost jobs after the FBI informed employers that he was a communist, and his prospects appeared bleak. He made the trip to Princeton to see Bohm.

On Nassau Street, the two men encountered Oppenheimer as he emerged from a barbershop. Although he had not seen Lomanitz for years, they had stayed in touch. Oppenheimer had written to him in 1945 with sympathy for his difficulties and encouragement to hold on. Now Bohm and Lomanitz explained their predicament. Lomanitz later recalled Oppenheimer becoming agitated and exclaiming that all was lost because an FBI man was on the committee. Oppenheimer later described their encounter as a brief conversation in which he had advised them to tell the truth; according to his account, they replied that they would not lie. The encounter exposed both his concern and his fear: he recognized the danger facing his former students, but also knew that the investigation could reach him.

Bohm testified before the committee in May and again in June. On the advice of his lawyer, the civil-liberties attorney Clifford Durr, he refused to cooperate, invoking the First and Fifth Amendments. Princeton University issued a statement supporting Bohm for the time being. On June 7, Oppenheimer appeared at a closed executive session. He was questioned by six congressmen, including Richard Nixon, ostensibly in his capacity as chairman of the General Advisory Committee of the Atomic Energy Commission. The interrogators were not principally interested in nuclear-weapons policy; they wanted information about atomic spies. Oppenheimer appeared without a personal lawyer, brought the Commission’s general counsel, Joseph Volpe, and was cooperative and forthcoming over two hours. Asked whether he knew that a communist cell existed among scientists at the Radiation Laboratory, he denied such knowledge.

Consequences for the scientists

The costs of the inquiry continued after the hearings. More than a year later, Bohm and Lomanitz were both indicted for contempt of Congress. Bohm was arrested on December 4, 1950, and released on $1,500 bail. Princeton suspended him from his teaching duties and barred him from campus. Although he was acquitted six months later, the university did not renew his contract when it expired that June. The sequence made clear that acquittal did not restore what the investigation had taken: his position at Princeton was gone.

Lomanitz’s consequences were harsher still. After his testimony, Fisk University fired him. For two years he worked as a day laborer, tarring roofs, loading burlap bags, and trimming trees. Tried for contempt of Congress in June 1951 and acquitted, he could find only work repairing railroad tracks for $1.35 an hour. He did not obtain another teaching job until 1959. His experience shows how the investigation’s repercussions could persist through employment and professional exclusion even when a contempt charge ended in acquittal.

Significance

The investigation’s reach cannot be measured only by the answers recorded in the committee room. It summoned four scientists, put a suspected wiretap and an unprovable accusation at the center of the inquiry, and placed former friends and colleagues under pressure to decide what they could say about one another. Bohm’s refusal to testify about others and Oppenheimer’s advice to tell the truth mark different responses to that pressure; neither prevented the ensuing professional damage.

For Oppenheimer, the episode joined his public role to the vulnerabilities of his earlier political associations. His brief meeting with Bohm and Lomanitz showed that he remained in contact with former students, but also that he feared what the committee might do. The investigation’s consequences were therefore personal as well as institutional: it endangered careers, narrowed the space for association, and made the defense of a colleague itself a source of risk.