What happened with Oppenheimer’s revoked security clearance

Miguel Ortiz
Jul 31, 2023
3 minute read

J. Robert Oppenheimer at the Guest Lodge, Oak Ridge, in 1946 (left). Mushroom cloud of ‘Gadget’ over Trinity, seconds after detonation (right).


Despite his accomplishments, Oppenheimer’s security clearance was unjustly revoked after the war and lasted 55 years after his death.

J. Robert Oppenheimer is one of the most important Americans, and perhaps people, in history. As the director of the Los Alamos Laboratory during WWII, he was a critical member of the Manhattan Project and instrumental in the creation of the world’s first nuclear bombs. Oppenheimer was even nicknamed the “father of the atomic bomb.” Despite his accomplishment, Oppenheimer's security clearance was unjustly revoked after the war. This went uncorrected for 55 years after his death.

In 1904, Oppenheimer was born in New York City to a German Jewish family. He graduated from Harvard University with a degree in chemistry in 1925 and earned his PhD in physics from the University of Göttingen in Germany two years later. When Oppenheimer was recruited into the Manhattan Project in 1942, it was neither his immigrant background nor his study abroad that delayed his clearance; it was his association with communists.

Unlike Oppenheimer, Einstein was never given a clearance due to his birthplace and political ideology (Public Domain)

In the 1930s, Oppenheimer supported many progressive, left-wing causes. His views on social reform were later classified as communist in nature and he backed his views with financial contributions. Oppenheimer notably donated money to the Republican faction of the Spanish Civil War which included communist and socialist groups. This money was channeled through known or suspected members of the Communist Party USA. However, Oppenheimer denied ever being a member himself.

In 1936, Oppenheimer began a relationship with Jean Tatlock, a known communist and writer for the Western Worker communist newspaper. Three years later, after Tatlock broke up with Oppenheimer, the scientist began a relationship with Katherine "Kitty" Puening, a former Communist Party member. Neither of these relationships helped Oppenheimer's security clearance, especially after he briefly rekindled his relationship with Tatlock during his marriage to Puening. Beyond his romantic relationships, Oppenheimer's own brother was also a former Communist Party member.

Oppenheimer (right) and Groves in 1942 (Public Domain)

It took Brig. Gen. Leslie Groves, Jr., director of the Manhattan Project, to get Oppenheimer his clearance. "In accordance with my verbal directions..., it is desired that clearance be issued to Julius Robert Oppenheimer without delay irrespective of the information which you have concerning Mr Oppenheimer. He is absolutely essential to the project," Groves wrote. Unfortunately, his essential contributions to the bomb didn't protect Oppenheimer from political persecution after the war.

Chief among Oppenheimer's political enemies was Rear Admiral Lewis Strauss. As the Chairman of the Atomic Energy Commission, Strauss strongly opposed the exportation of radioactive isotopes to other countries. Oppenheimer testified before Congress and humiliated Strauss, calling the isotopes "less important than electronic devices but more important than, let us say, vitamins." Oppenheimer also actively opposed the development of the hydrogen bomb which Strauss supported. As a result, Strauss pressed hard for Oppenheimer's clearance to be revoked.

Oppenheimer (second from the left) with the rest of the General Advisory Committee of the Atomic Energy Commission (Public Domain)

In November 1953, William Borden, the former executive director of the Congressional Joint Committee on Atomic Energy, wrote a letter to FBI Director J. Edgar Hoover accusing Oppenheimer of being a Soviet spy. This led to an investigation and, in April and May of 1954, a secret security hearing. In addition to the revelation of a story that he fabricated to protect a communist friend, Oppenheimer's extensive associations with current or former members of the party were levied against him and his security clearance was revoked. This ended Oppenheimer's access to government atomic secrets and his career as a nuclear physicist.

Although he was later given the Enrico Fermi Award, a presidential award for lifetime achievement in energy, Oppenheimer never regained his security clearance. On December 16, 2022, over 55 years after his death on February 18, 1967, Oppenheimer received some justice. Citing that "the AEC failed to follow its own rules" in the Oppenheimer investigation and hearing, U.S. Secretary of Energy Jennifer Granholm vacated the 1954 decision to revoke Oppenheimer's clearance. Although there was no new adjudication, the secretarial order formally recognized Oppenheimer's unjust treatment and the government's persecution of a man who served his country faithfully.