Among the countless names thrown around in Christopher Nolan’s Oppenheimer, one of the most pivotal is Chevalier, whose incident ruined Oppenheimer’s career. Back in 2023, Oppenheimer was released with incredible anticipation. The three-hour epic boasts an incredible cast and impressive visuals thoughtfully planned by Nolan. The film is also full of significant historical moments that shed light on the true story of J. Robert Oppenheimer. By doing this, Oppenheimer showcases different sides of its titular character.

While the creation and detonation of the atomic bomb are massively important to Oppenheimer, these events are one part of a larger puzzle. The movie delves into Oppenheimer’s early years at the University of Cambridge and his move to California, along with the decades after Los Alamos and Hiroshima and Nagasaki. However, what may be the biggest plot point surrounding Oppenheimer’s later years is the Chevalier Incident and the 1954 AEC security hearing that lost the scientist his Q clearance. Though the incident itself seems minimal when it happens, it ends up snowballing into an act that costs Oppenheimer everything.

Oppenheimer’s Connection To Haakon Chevalier Explained

Oppenheimer Met Chevalier At Berkeley

J. Robert Oppenheimer first met Haakon Chevalier in 1937 (via Broad). At that time, the men both worked at the University of California, Berkeley, with Oppenheimer working in the physics department and Chevalier teaching Romance languages. Haakon Chevalier was born in New Jersey in 1901 to Norwegian and French parents (via Federal Bureau of Investigation). Before meeting Oppenheimer, he was beginning to establish himself as a writer and translator. In 1937, Oppenheimer and Chevalier bonded over their shared beliefs. This led them to found a branch of the Berkeley teacher’s union which held events supporting leftist ideas (via Broad).

In the years after the Chevalier Incident, this kinship between Oppenheimer and Chevalier came under serious fire. This was because Chevalier was one of many people that Oppenheimer befriended who had communist ties (via Herken). Along with Chevalier, Oppenheimer’s wife, Kitty, and his brother, Frank, were both former members of the Communist Party USA. Oppenheimer’s girlfriend, Jean Tatlock, was also a known communist. Therefore, when anti-communist sentiment increased following World War II, Oppenheimer’s relationship to communism was brought into question. Ultimately, these bonds led to the security hearing that stripped him of his Q clearance (via American Prometheus).

What Happened During Oppenheimer’s Chevalier Incident

Chevalier Told Oppenheimer About A Spy

The Chevalier Incident is a small moment considering how much trouble it ended up causing Oppenheimer. According to Herken, in the early months of 1943, Chevalier joined Oppenheimer at his home for what Oppenheimer presented as a dinner party with friends. However, the night takes a surprising turn when Chevalier meets Oppenheimer in his kitchen and tells him a disturbing fact. Chevalier tells Oppenheimer that a scientist named George Eltenton is capable of getting information to the Soviet Union. Oppenheimer quickly tells his friend he’s uninterested in this concept, and Chevalier drops it. Yet, the “incident” lived on.

The Chevalier Incident spiraled when J. Robert Oppenheimer tried to hide that it happened. In August 1943, Oppenheimer told authorities at the Manhattan Project that three men at Berkeley had been pressured to reveal nuclear secrets. He blamed the incident on an individual who worked at Shell Oil named Eltenton. Months later, when he was probed about this revelation, Oppenheimer revealed that the culprit was actually Chevalier, who had approached Oppenheimer’s brother. Three years later, Oppenheimer gave yet another foggy representation of the facts before admitting that Chevalier had approached him about transmitting nuclear information to the Soviet Union (via Herken).

How The Chevalier Incident Played A Role In Oppenheimer’s Hearing

Chevalier Made Oppenheimer Suspicious

In the 1940s, Oppenheimer’s strange behavior surrounding the Chevalier Incident was dismissed because of his role in the Manhattan Project (via Herken). In 1954, the same wasn’t true. When J. Robert Oppenheimer was called into a private security hearing in front of the Atomic Energy Commission, the Chevalier Incident played a significant role in proving Oppenheimer’s suspicious nature. According to American Prometheus, investigators used Oppenheimer’s lies to argue that the scientist was trying to hide his communist ties. They theorized that the information leak at Los Alamos was Oppenheimer’s fault and that he had given the information to Chevalier.

In reality, Oppenheimer was simply trying to protect his friend (via American Prometheus). Though he likely would have benefited from telling the truth all along, his lies were simply a result of preserving Chevalier’s reputation. Unfortunately, Oppenheimer’s actions led to his security clearance being revoked in 1954. If the Chevalier Incident had not happened, it is unclear whether the same result would have occurred. In this way, the Chevalier Incident is a brief but incredibly momentous scene in the grand scheme of Christopher Nolan’s Oppenheimer, and the real life of J. Robert Oppenheimer.

Sources: Federal Bureau of Investigation, Broad, Herke