Oppenheimer's correction of his testimony on Bernard Peters

J. Robert Oppenheimer’s correction of his testimony about Bernard Peters came after a private congressional account became a public accusation that threatened Peters’s scientific career. Oppenheimer had described Peters in terms that made his escape from Dachau concentration camp and his opposition to fascism appear evidence of Communist sympathies and support for violent action. When Peters challenged the report, Oppenheimer confirmed that he had given the testimony, called it a terrible mistake, and ultimately published a correction affirming Peters’s denial of party membership. The episode exposed both the practical danger of political testimony in the period and the gap between Oppenheimer’s damaging words and his later defense of Peters’s right to a scientific career.

The leaked testimony and its consequences

The day after Oppenheimer testified before the House Committee on Un-American Activities, Peters spent about twenty minutes before the committee, denying that he had belonged to the Communist Party in Germany or the United States. He also denied that his wife, Hannah Peters, had ever been a party member and said he did not know Steve Nelson. On his way back to Rochester, Peters stopped in Princeton to ask Oppenheimer what he had told the committee. Oppenheimer reassured him that God had guided the questions so he had said nothing derogatory.

That reassurance did not prepare Peters for what followed. A week later, Oppenheimer’s closed-session testimony was leaked to the Rochester Times-Union. Its headline reported that Oppenheimer had once called Peters “quite red.” The accompanying account presented Peters’s escape from Dachau by “guile” and his criticism of the American Communist Party as evidence of a taste for armed revolution. The leak converted remarks made under questioning into a public description of Peters’s political character, with immediate implications for his standing among colleagues at the University of Rochester.

Peters recognized the danger in part because he had faced a similar episode the previous year. After a newspaper story suggested he might face an espionage investigation, he had sued for libel and received an out-of-court settlement of one dollar. He now publicly denied Oppenheimer’s account. Peters explained that he had admired the fight against the Nazis and the people who died in concentration camps, but maintained that he had never joined the Communist Party. He acknowledged that his views were not orthodox: he opposed racial discrimination and considered socialism desirable. He nevertheless insisted that these positions did not make him a Communist.

Peters challenges Oppenheimer

Peters wrote Oppenheimer the same day, enclosing the newspaper clipping and asking whether he had really made the statements attributed to him. He accepted that he had advocated “direct action” against fascist dictatorships, but challenged the implication that he had urged such action against a government freely supported by its people. He also questioned Oppenheimer’s account of his supposed street battles, remarking that he wished he had such a story to tell. The letter conveyed more than disagreement over a newspaper’s wording: Peters was asking his former mentor to answer for testimony that could place his employment and reputation at risk.

The possibility of legal action sharpened the dispute. Peters was angry enough to ask his lawyer whether he had grounds to sue Oppenheimer for libel. Five days after the letter, on June 20, Oppenheimer telephoned Peters’s lawyer, Sol Linowitz, with a message for Hannah: he was very disturbed by the newspaper story, said it misrepresented his testimony, and was anxious to speak with Bernard. But his initial explanation did not erase the fact that Peters had been reassured in Princeton and then found his political record described publicly in far more damaging terms.

Their eventual conversation was difficult. Frank Oppenheimer took Peters to see his brother while J. Robert Oppenheimer was visiting Berkeley. Peters later recalled that Oppenheimer first refused to say whether the newspaper report was true or false. When pressed, he confirmed that it reflected his testimony. He called what he had said a terrible mistake and explained that he had not been prepared for the questions; only after seeing the words in print had he understood how damaging they were. When Peters asked why Oppenheimer had misled him in Princeton, Oppenheimer became visibly embarrassed and had no explanation. Peters clarified that he had attended open-air Communist rallies in Germany but had never joined the Party.

The published correction

Oppenheimer agreed to write to the editor of the Rochester newspaper. Published on July 6, 1949, the letter stated that Peters had given him “an eloquent denial” of ever being a Communist Party member or advocating the violent overthrow of the United States government. Oppenheimer said, “I believe this statement.” The correction thus addressed the central factual dispute: it accepted Peters’s denial rather than treating his anti-fascist record as proof of Communist membership or revolutionary intent.

The letter also moved beyond Peters’s individual case to defend political expression in science. Oppenheimer wrote that “Political opinion, no matter how radical, or how freely expressed, does not disqualify a scientist for a high career in science. . . .” That public principle sat uneasily beside the testimony that had helped make Peters’s political views a professional liability. The correction did not withdraw the original remarks in every respect, and Peters judged it “a not very successful piece of double-talk.” Yet he recognized its immediate practical value: it helped salvage his job at the University of Rochester.

A partial repair, not a return to security

Keeping his university position did not restore Peters’s access to the government research system. Without classified work and government projects, he came to regard his prospects in the United States as effectively blocked. In late 1949, the United States Department of State refused him a passport after he expressed an intention to travel to India. The department relented the following year, and Peters accepted a teaching post at the Tata Institute of Fundamental Research in Bombay. When his passport was again refused in 1955, he took German citizenship. In 1959, he and Hannah moved to Niels Bohr’s institute in Copenhagen, where he spent the remainder of his career.

The correction therefore had a limited but consequential result. It helped prevent the leaked testimony from costing Peters his Rochester job, but could not secure his continued participation in classified research or remove the restrictions shaping his professional choices. Oppenheimer’s admission that he had made a damaging mistake and his published defense of political freedom mattered; so did the delay, the evasive initial response, and the career consequences that continued after the correction. The episode made visible how a mentor’s testimony could injure a former student even without malicious intent, and how a public retraction could repair one immediate danger without undoing the larger pressures surrounding political dissent.