Soviet Union

The Soviet Union occupies a shifting place in the book: it is praised as evidence of socialist public-health policy, scrutinized as a state of political terror, and treated as a decisive actor in the changing alignments of the Second World War and the early nuclear debate. Oppenheimer’s changing view of it was not a simple conversion from sympathy to hostility. It developed through specific encounters, reports, and political crises that altered what he believed socialism, communism, and resistance to fascism required.

A model for reform

In 1935, Thomas Addis attended an academic conference of the International Physiological Congress in Leningrad. He returned with glowing accounts of the Soviet Union’s progress in public health, particularly its doctors’ experiments with cadaveric kidney transplants as early as 1933. The visit strengthened his advocacy of national health insurance. When he pressed that cause, the American Medical Association eventually expelled him; colleagues at Stanford, however, treated his admiration for the Soviet system as an eccentricity of a respected scientist. Addis’s example places the Soviet Union within a domestic argument over health care and social reform, not only a dispute over foreign policy.

Oppenheimer encountered favorable accounts of the Soviet experiment through books and people in his political circle. Around 1935, his father lent him a sympathetic account of Soviet Communism, which he read favorably. His friends also recalled that he read Marx, and in 1937 Haakon Chevalier heard that Oppenheimer had read Lenin’s complete works. These details establish a serious intellectual interest, but they do not by themselves prove party membership or settle the meaning of his politics. The book distinguishes Oppenheimer’s engagement with socialist ideas from the more categorical claims others made about his affiliations.

The causes that drew Oppenheimer toward the American left were also connected to conditions at home. He supported campaigns involving desegregation, working conditions for migratory farm workers, civil liberties, and opposition to fascism. He contributed money to causes solicited through the Communist Party USA, including Spanish relief, and later explained that he had not thought the donations might serve other purposes than those he intended. At the time, he did not regard Communists as dangerous, and some of their declared objectives seemed desirable to him. The Soviet Union mattered within this political landscape, but the evidence presents Oppenheimer’s sympathies as bound up with reform campaigns and anti-fascism rather than reducible to allegiance to a foreign state.

Reports of repression and political rupture

That favorable picture was challenged by reports of Stalin’s purges. By 1938, American newspapers were carrying accounts of political terror directed at alleged enemies inside the Soviet Communist Party. Oppenheimer later recalled that he had read about the trials and could find no account of them that did not condemn the Soviet system. Unlike Chevalier, who publicly defended the Moscow trial verdicts, Oppenheimer did not defend the purges. The difference did not immediately erase their shared left-wing commitments, but it marked a growing divergence in how they interpreted the Soviet state.

In the summer of 1938, physicists George Placzek and Victor Weisskopf visited Oppenheimer at his New Mexico ranch after spending months in the Soviet Union. They described the arrest of Austrian engineer Alex Weissberg, who had been detained for associating with them, and the fear that followed when their friends would no longer acknowledge them. Oppenheimer initially met their account with skepticism, then pressed them with questions. Sixteen years later, he told his interrogators that their reports had seemed solid and unfanatical and had left a deep impression: the Soviet Union appeared to him as a land of purges, terror, gross mismanagement, and a long-suffering population.

Weisskopf remembered the conversations as a turning point. Oppenheimer, he said, remained substantially committed to communism and to socialism as a desirable development, but the reports from the Soviet Union shook him and began his movement away from the Communist Party. The distinction matters: learning about state repression did not make him abandon every left-wing principle. It did, however, unsettle the assumption that those principles could comfortably coexist with loyalty to the Soviet political system. By the autumn, friends noticed that he no longer praised the Soviet Union so freely.

The pact and the war in Europe

The Soviet Union’s 1939 nonaggression pact with Nazi Germany made this tension public and urgent. On August 24, 1939, the Soviet Union announced that it had signed the pact the previous day; a week later, Germany and the Soviet Union invaded Poland as the Second World War began. Oppenheimer responded in a letter to physicist Willie Fowler with skepticism about the political maneuvering and a bleak acknowledgment that the German advance into Poland was underway. The agreement confused many people in left-intellectual circles, and some American Communists left the Party.

Chevalier remained loyal to the Communist Party and defended the pact as a necessary strategic decision. Oppenheimer’s name was absent from an open letter Chevalier signed arguing that the Soviet Union and the totalitarian states were not fundamentally alike. Chevalier later recalled Oppenheimer trying to explain the pact as a treaty of necessity, shaped by Western appeasement of Hitler at Munich. The episode shows why political positions cannot be read backward from Oppenheimer’s earlier sympathies: he was attempting to make sense of a Soviet action that strained the anti-fascist commitments he shared with his circle.

The collapse of France in 1940 further changed the emphasis of Oppenheimer’s argument. At an American Physical Society conference in Seattle, he spoke about the fall of Paris as a threat to Western civilization and argued that the pact meant there could be no political accommodation with the Communists. For him, the immediate danger posed by Nazi Germany had displaced other considerations. When Germany invaded the Soviet Union on June 22, 1941, Oppenheimer interpreted the reversal as destroying the notion that fascism and communism were simply interchangeable totalitarian systems. He and Chevalier welcomed the prospect of Communists joining the Western democracies against Hitler. The Soviet Union’s changing position thus repeatedly altered the practical meaning of their shared anti-fascism.

From wartime ally to nuclear adversary

After the Japanese attack on Pearl Harbor, Oppenheimer rarely attended the Berkeley group’s meetings; when its members did meet, Chevalier recalled, they mostly discussed the war and events at home. Chevalier continued to describe Oppenheimer as sharing his socialist ideal until Oppenheimer left Berkeley in 1943, while also acknowledging that he was not an automatic follower of a party line. Their recollections preserve a difference between political sympathy and disciplined party allegiance that remained important to later arguments about Oppenheimer’s past.

In the postwar nuclear debate, the Soviet Union became central not as a distant model of social policy but as the opposing power whose atomic capability shaped American choices. During a visit to Princeton on November 16, 1949, George Kennan and Oppenheimer discussed the atomic problem and the possibility that the president might propose a moratorium on building a hydrogen bomb. Oppenheimer found Kennan’s suggestion reasonable but warned that Washington’s prevailing assumptions about safeguards had become rigid, and that the proposal would have to meet arguments that it was too dangerous. Kennan then drafted a possible presidential statement against proceeding with a weapon of almost unlimited destructive power, reasoning that it had no purely military use, that absolute security was impossible, and that building it would encourage others to do the same.

A contrasting response to the Soviet threat appears in the outlook of William Liscum Borden. After seeing a German V-2 rocket during a wartime mission, Borden became convinced that the United States would eventually face direct attack by transoceanic rockets. He later warned of a possible nuclear Pearl Harbor and had supported an ultimatum challenging the Soviet Union to choose between atomic war and atomic peace. Where Oppenheimer and Kennan considered whether restraint could avert an arms race, Borden saw danger in any course that might slow American weapons development. The Soviet Union therefore functions in the narrative as more than a geographical setting: it is the contested reference point through which competing claims about security, political commitment, and nuclear policy take shape.