How Soviet Espionage of Manhattan Project May Have Impacted Cold War

Originally published on Medium


The Manhattan Project, a US effort undertaken between 1942 and 1945, aimed to develop a nuclear weapon that would help end World War Two. One key question, with implications extending to the emerging Cold War, centers on the degree to which Soviet espionage efforts successfully created parity in the arms race.

The background extends to Otto Hahn and Fritz Strassman, a pair of German scientists who discovered nuclear fission in 1938. This discovery opened the door to a potential atomic bomb. Albert Einstein and Leo Szilard researched the subject in depth. The following year, they wrote to US President Franklin D. Roosevelt describing the new type of “extremely powerful” bomb on the horizon.

As early as 1941, spies from the Soviet Union became aware of a US-led atomic project, and Soviet Premier Joseph Stalin launched Operation ENORMOZ, which had the aim of infiltrating the Manhattan Project. Machinist David Greenglass delivered inside information from the program, including sketched elements of the atomic bomb, to siblings Julius and Ethel Rosenberg, who then relayed the information to the Soviets. Becoming aware of these efforts, the US created project VENONA. It postulated that Klaus Fuchs relayed critical details of US nuclear programs to Russia over six years.

The effect of this espionage jumpstarted the USSR’s nuclear program. With the Soviet Union occupied with major battles with Germany, such as the Battle of Stalingrad in 1941, it did not initially have the resources to create an atomic program. However, inside information on America’s preparation for the Manhattan Project, coupled with details on the US seeking to prevent Soviet acquisition of uranium, led the USSR to launch its own atomic project. While some years behind America’s effort, it did not lag by much.

The culmination of the Manhattan Project came on July 16, 1945, when the Trinity test provided proof that the US had a trio of functional atomic weapons. By contrast, the USSR’s achievement of a successful atomic bomb test occurred on August 29, 1949. Though significantly behind the US timeline, many believed that the details obtained accelerated their efforts. Otherwise, the Soviets would not have developed a workable nuclear bomb until the mid-1950s.

The Soviet efforts had a significant geopolitical impact. It meant the US did not stand as the sole nuclear-armed superpower during post-war settlements and emerging Cold War dynamics in Eastern Europe and beyond. The Soviet’s holding of nuclear weapons created a long-lasting stasis between the two sides, as the prospect of “mutually assured destruction” helped avoid direct conflict between the two superpowers.

One interesting moment in this emerging dynamic occurred at the Potsdam Conference on July 24, 1945. US President Harry Truman officially informed Stalin that the US now had “a new weapon of unusual destructive force.” Accounts of the Soviet premier’s response to this vary, with Truman’s memoirs recounting a reply of “Yes, and I hope you use it against Japan.”

By contrast, British Foreign Secretary Anthony Eden recalled an ambiguous reply of “thank you,” while Stalin’s interpreter remembered the Soviet leader simply nodding his head. This discrepancy begs the question of the motivations and justifications that underlie differing historical accounts. It also points to different strategic viewpoints that the arc of the Cold War arms race would clarify.