Oppenheimer’s inconvenient truth: He was a secret Communist, historians say

J. Robert Oppenheimer went to his grave holding onto a painful secret. He repeatedly denied to the U.S. government that he joined the Communist Party while teaching physics at UC Berkeley, but the “overwhelming” evidence shows that he was a member and opened himself up to perjury charges by lying about it.

A retired Stanford history professor and one of Oppenheimer’s biographers are among a group of historians who are speaking up about the famed scientist’s “secret” party membership, as Christopher Nolan’s film, “Oppenheimer,” renews debate about his legacy and shows him facing post-World War II persecution for his left-wing politics and for having friends, family members and an ex-girlfriend who belonged to the Communist Party.

Barton Bernstein, a Stanford University history professor emeritus, and Gregg Herken, author of the 2002 book “Brotherhood of the Bomb,” agree that Oppenheimer was a victim of McCarthy-era excesses. They also say there’s no evidence that “the father of the atomic bomb” ever spied for the Soviet Union or that he wasn’t loyal to the United States.

But Bernstein and Herken dispute a central argument of Nolan’s film and of “American Prometheus,” the 2005 Pulitzer Prize-winning book on which it’s based. These works insist that Oppenheimer never joined the party in the 1930s, with “American Prometheus” authors Kai Bird and Martin J. Sherwin concluding that Oppenheimer was a “classic fellow-traveling New Deal progressive who admired the party’s opposition to fascism in Europe and its championing of labor rights at home.”

According to Bernstein and Herken, evidence of Oppenheimer’s party membership has become available over the past two decades. The evidence includes a “smoking gun” excerpt of an ex-party member’s unpublished memoir, KGB intelligence documents released after the collapse of the USSR and the accounts of others who were active in Bay Area Communist circles.

“Oppenheimer repeatedly lied during and after World War II to the U.S. government,” Berstein wrote in an essay published shortly before the July 21 release of “Oppenheimer.” “The evidence of such CP membership is overwhelming, and that means he also committed perjury on at least a few occasions over a number of years.”

Herken, also an emeritus professor of American diplomatic history at UC Merced and UC Santa Cruz, said Oppenheimer was a member of a secret “closed unit” of the party’s professional section in Berkeley, from 1937 to early 1942. According to the former party member, historian Gordon Griffiths, this unit wasn’t involved in espionage. It allowed members to share views on international events and to receive occasional briefings by senior party officials.

Neither Herken nor Bernstein believe that calling attention to Oppenheimer’s party membership in 2023 is “latter-day McCarthyism.” Instead, they said that raising the issue shows the true complexity of this brilliant but conflicted man’s situation, as well as the impact that toxic Cold War politics had on this country.

If Oppenheimer hid this secret, it could explain why he, “a forceful, charismatic” person, “fell apart” when confronted about his part membership in a hostile 1954 hearing before the Atomic Energy Commission, Bernstein told this news organization. It could also explain why he thereafter retreated from policy debates about protecting the world from the nuclear weapons he and the United States helped to create.

“It’s important that the history gets Oppenheimer right,” Herken told this news organization. Given what Oppenheimer faced at the height of McCarthyism — when FBI director J. Edgar Hoover equated communism with treason — Herken said, “I can understand why he felt he had to lie about that, and to even lie under oath.” Herken also believes that the lies Oppenheimer told about his party membership haunted him for the rest of his life.

Oppenheimer first denied being a party member in the summer of 1943, as he was applying for a a security clearance to direct the bomb-development efforts in Los Alamos. During that process, he met with Lt. Col. John Landsdale, the security chief for the Manhattan Project’s military commander, Gen. Leslie Groves, according to “American Prometheus.” At one of those meetings, Landsdale wondered whether Oppenheimer was about to reveal that he had been in the party and to explain how he had severed his connections.

But no such admission was forthcoming, and Oppenheimer again denied his membership to FBI agents in 1946 and during the 1954 hearing, at the end of which he was stripped of his security clearance.

Bernstein said it’s not clear whether Oppenheimer kept quiet about his party membership in 1943 because it could have disqualified him from the Manhattan Project. But after that, “he had to stick to his story because he had signed affidavits repeatedly that he had not been a communist,” Bernstein said.

“If he claimed otherwise, that would be evidence of perjury, so he had to keep lying,” continued Bernstein, who has published extensively on Oppenheimer’s 1954 hearing. “And perjury is worse than losing your security clearance. If you lose your security clearance you can still earn $25,000 a year, as director of the Institute of Advanced Studies at Princeton. If you commit perjury you may be wearing a striped shirt somewhere behind bars.”

Bernstein and Herken said their views on Oppenheimer’s party membership have evolved over time. Bernstein said he long minimized the possibility, while Herken said he offered a “Rashomon”-like approach to the question in his 2002 book. But they have since concluded that Oppenheimer was in the party, based on new evidence that subsequently became available and confirmed existing accounts.

A key source for Oppenheimer’s alleged party membership has been Haakon Chevalier, a professor of French literature at Berkeley who was Oppenheimer’s close friend. Chevalier also was a Communist, and “the Chevalier affair” became the focus of the case against Oppenheimer in his 1954 hearing. In Nolan’s film, Chevalier is seen approaching Oppenheimer in the kitchen of Oppenheimer’s Berkeley home and saying he knows a way to share information about his work with scientists in Russia, who are presumed to be allies. Oppenheimer reportedly replied, “That’s treason.”

According to Chevalier’s private writings, which Herken shares on his book’s website, the French scholar said that Oppenheimer was in the secret closed unit and wrote two 1940 pamphlets on behalf of the UC Berkeley faculty committee of the Communist Party.  In her diary, Chevalier’s ex-wife, Barbara, confirmed his account of Oppenheimer’s CP membership. She said the physicist joined the party after reading Marx on a cross-country train ride, but said his membership was “very secret indeed.”

Herken also interviewed the late physicist Philip Morrison, who had been one of Oppenheimer’s graduate students and a party member. Morrison told Herken in 2000 that Oppenheimer penned another Party-line pamphlet that he delivered to the printer on his behalf. Meanwhile, KGB archival documents, which became available in 2009, show that Oppenheimer was identified as a potential intelligence source on the basis of his Community Party membership, historians John Earl Haynes and Harvey Klehr wrote in their 2012 article, “J Robert Oppenheimer: A Spy? No. But a Communist Once? Yes.” Haynes and Kleher said the Soviets lost interest in Oppenheimer after learning that he left the party in 1942, while Herken also said that efforts to recruit him as a spy failed.

For Herken, the “smoking gun” is Griffiths’ unpublished memoir. The University of Washington historian, who died in 2001, was the Communist Party liaison to the Berkeley unit. He wrote that the unit met twice a month at Chevalier or Oppenheimer’s home to discuss international events, review party literature or craft unsigned reports to faculty colleagues. No one in this unit carried a card, and Oppenheimer didn’t pay dues like rank-and-file members because he was independently wealthy, so his more generous donations went through “a special channel.”

Griffiths said there was nothing “subversive or treasonable” about their meetings and they didn’t talk about “exciting developments in theoretical physics,” according to an excerpt available on Herken’s website. But he agreed that the record needed to be set straight about Oppenheimer and lamented that “well-intentioned liberals” tried to defend him by downplaying his party membership.

Griffiths wrote that the question about Oppenheimer should always have been whether his party membership “would constitute an impediment to his service in a position of trust.” The verdict of Bernstein and Herken is that it didn’t affect his loyalty, with Haynes and Klehr saying it’s unfortunate that the scientist wouldn’t or couldn’t come clean about his party membership: “Knowing what we know now, America’s public interest would have been best served if Oppenheimer had been able to continue in his role as a consultant to the government on various atomic and security projects,” they said.