Later this summer, director Christopher Nolan’s anticipated film on the life of J. Robert Oppenheimer will hit theaters. Oppenheimer, known as the “father of the atomic bomb,” was the American theoretical physicist who, as part of the Manhattan Project, ran Los Alamos National Laboratory. His lab built the bomb. On its first successful test, Oppenheimer famously quoted the Bhagavad Gita: “Now I am become Death, the destroyer of worlds.”

Simply enumerating Oppenheimer’s non-wartime contribution to the field of physics would itself require one to hold a doctorate in the scientific discipline, but it goes without saying that unlike most titans in the field of physics, Oppenheimer’s achievements in ending World War II were very, very visible.


Robert Oppenheimer’s story is fascinating—and not only because of his astounding contribution to the fate of humankind. By winning the race to build the atomic bomb, Oppenheimer essentially saved the lives of 32 million people, according to war veteran and historian Tom Lewis.

Moreover, Oppenheimer felt certain he was in a race against Germany to build the bomb. (His analog in Germany was no less than Werner Karl Heisenberg, who won the Nobel Prize in 1932 for creating quantum mechanics. We now know Heisenberg intentionally sabotaged Germany’s research in atomic weapons.) The United States was also working to beat the Soviet Union to the bomb, though the Soviet nuclear program consisted mostly of infesting spies in the Manhattan Project—a reflection of poor security on the part of the Army and the FBI, but something that would later make Oppenheimer’s life a living hell.

Aware more than most of the sheer power of nuclear weapons, and their capability to literally end human civilization, Oppenheimer used his influence as chairman of the U.S. Atomic Energy Commission’s General Advisory Committee to argue against an atomic arms race with the Soviet Union, and for a general halt to nuclear proliferation overall.

Moreover, he argued against the creation of an American hydrogen—also called a thermonuclear—bomb. Where the atomic bombs dropped on Japan had a destructive force on the order of 12 to 23 kilotons, a hydrogen bomb would have a destructive capability of 10,400 kilotons.

When the Americans created theirs, the Soviets naturally responded in kind, creating a 50,000 kiloton bomb. For comparison, an atomic bomb would take out the Washington D.C. metropolitan area; a thermonuclear bomb would flatten the entirety of Washington D.C., and a good bit of Baltimore for good measure. This simulator offers a pretty good idea of just how horrifying these weapons are. 


Despite all he had done for the war effort and American science more broadly, when the Red Scare and McCarthyism infected Washington D.C. like some terrible plague, Oppenheimer was one of many accused of being a Soviet spy.

The physicist had a lot of things working against him. First, he was Jewish, which made him suspect as a matter of course in the paranoid age of the 1950s. He was a first generation American, which didn’t help. In the early 1930s, he was in his mid-20s, and like so many twenty-somethings, he was progressively minded. He donated to leftist organizations, and knew a great many people who would, in fact, become Communists. (Notably, however, he was never a member of the Communist Party.)

None of this even at the time would have been considered that bizarre. Recall that in the thirties, the United States was mired in the Great Depression, and Franklin Roosevelt was elected president in a landslide based in large part of his progressive ideals.


When Oppenheimer joined the Manhattan Project in 1942, the FBI already had a file on him. His left-leaning sympathies were known, as was the fact that he associated with known leftists. Oppenheimer was on the executive committee of the American Civil Liberties Union, which the feds considered to be a Communist Party front. Oppenheimer was even on the FBI’s “arrest list,” which was to be implemented in the case of a national emergency.

It is doubtful that Oppenheimer knew the extent to which the FBI distrusted him, though he certainly didn’t respect them very much. He was up front with them during his security clearance interview that “I am not a Communist, but I have been a member of just about every Communist Front organization on the West Coast.”

It wouldn’t have taken much effort. Communists were not in short supply in academia in the 1930s and 40s, or even today. Particularly in the field of theoretical physics, refugees from Europe flooded the United States, and would naturally have held far-left views in reaction to the literal fascism they had just escaped.

Despite his political leanings, the United States needed Oppenheimer’s brain, and granted him a “Q-level” security clearance. Notably, the Manhattan Project’s security arm, as well as the FBI, continued investigating Oppenheimer throughout his tenure of building the United States the atomic bomb. It was an extreme prototype of Continuous Vetting.

He might have emerged from the Red Scare unscathed had he not so vehemently opposed the Air Force’s plans after the war. Oppenheimer, aware of the advantages of the atomic bomb, but afraid of an arms race to build bigger and bigger bombs, gave express support for small tactical nuclear weapons that could be used on the battlefield by the U.S. Army. He also supported air defenses against nuclear attacks, which ran counter to the Air Force’s goal of a bigger nuclear footprint. But his opposition to the hydrogen bomb was the unforgivable sin.

The FBI was delighted to spread dirt on Oppenheimer to enemies he made as a result of his positions. All this culminated in William Borden, executive director of the United States Congress Joint Committee on Atomic Energy, former Army Air Forces officer, and a fanatical fan of more and bigger nuclear weapons, writing a letter to J. Edgar Hoover directly accusing Oppenheimer of being a Communist and Soviet spy.


In 1954, the government held a security hearing to determine whether Robert Oppenheimer, who had literally saved millions of Americans, was, in fact, a threat to the United States. The hearing lasted a month, with Oppenheimer testifying for 27 hours. He was essentially railroaded—a modern day Galileo, with the McCarthyites playing the role of the Church.

On May 27, 1954, the U.S. government stripped Robert Oppenheimer of his security clearance.

As a result, not only did the United States lose one of the finest minds in physics (and weapons development project management) to ever live, but in the aftermath, other prominent titans in physics—who might otherwise have been inclined to help the United States develop its nuclear program—withdrew entirely from government work. Wernher von Braun, the father of the American space program and the man who put Neil Armstrong on the moon, later scolded Congress, saying: “In England, Oppenheimer would have been knighted.”


Once the Soviet Union fell, and researchers gained access to the KGB archives, they mounted an intensive effort to find out once and for all whether Oppenheimer spied for the Soviet Union. They found that while Soviet agents repeatedly attempted to recruit the father of the atomic bomb, they were never successful. He never spied for the Soviet Union. He even, in fact, purged Soviet sympathizers from the Manhattan Project when they were discovered. In other words, he was a loyal American.

In 2022, Energy Secretary Jennifer Granholm cleared J. Robert Oppenheimer of any wrongdoing. The Department of Energy even reversed his clearance revocation. In a memo, Granholm said: “In 1954, the Atomic Energy Commission revoked Dr. Oppenheimer’s security clearance through a flawed process that violated the Commission’s own regulations. As time has passed, more evidence has come to light of the bias and unfairness of the process that Dr. Oppenheimer was subjected to while the evidence of his loyalty and love of country have only been further affirmed.”


The experience of Oppenheimer offers myriad lessons for clearance holders today, chief among them: Your clearance is not permanent, and regardless of your achievements or contribution to American national security, it can be taken away at any time without warning.

Oppenheimer fell victim to the Red Scare, which one hopes is anomalous in U.S. history, but some equivalent of J. Robert Oppenheimer today is certainly a possibility. Whether it’s the threat of deep fakes or a disastrous polygraph examination, cancel culture or CBD, security clearance policies may be set, but can suffer under the whims of congress, culture, and political convention.

Wartime applications aside, research that emerged from the Manhattan Project affected everything from the microscopic—revolutionizing cancer treatments, for example—to the infinite, enabling the exploration of the deep outer solar system. It is no exaggeration to say that the modern world was fundamentally shifted by a handful of scientists and engineers, chief among them: Albert Einstein. Wernher von Braun. Alan Turing. And deservedly so, but unjustly overlooked, Robert Oppenheimer, who brought an end to a World War, and paid a terrible price for doing so.


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David Brown is a regular contributor to ClearanceJobs. His most recent book, THE MISSION (Custom House, 2021), is now available in bookstores everywhere in hardcover and paperback. He can be found online at