First Soviet Atomic test. Joe-1, the American nickname for the first Soviet atomic test, referred to Joseph Stalin.
The American monopoly lasted scarcely four years. Even though the Soviets had been wartime allies, and even though the British and Canadians had been both allies and close collaborators on the Manhattan Project, the U.S. government asserted strict unilateral control over the manufacture of nuclear weapons after the war. Prior to 1945, there had been good reasons not to share any information with the Soviets. Though a partner in the fight against Nazi Germany, the Soviet Union had had an antagonistic relationship with the United States and Western Europe during the interwar period. During the war itself, it was doubtful whether the Soviets would withstand the German invasion. In these circumstances, it would have been foolish to share sensitive information with Moscow, because it could easily have ended up in Nazi hands. After the war, rising U.S.-Soviet tensions gave Washington cause to reconsider any thought of divulging its atomic secrets.
The Soviets made every effort to steal the Manhattan Project’s secrets. Thanks to both the high quality of their espionage and sympathy for their cause among certain Western scientists, they were startlingly successful. Their most valuable spy in Los Alamos was Klaus Emil Julius Fuchs (1911– 1988), a German-born physicist, devout communist, and longtime Soviet informer. So successful was he that none of his colleagues were aware of his covert activities. His work for Moscow was not discovered until 1950.
The information that he and others passed to the Soviets was of great use in both strategic and scientific terms. At the 1945 Potsdam Conference, the U.S. president Harry S. Truman (1884–1972) informed the Soviet leader Joseph Stalin (1879– 1953) that the United States had built a ‘‘powerful new weapon.’’ Long aware of the Manhattan Project thanks to the steady stream of information from Los Alamos, the Soviet leader feigned indifference, but was secretly concerned. There is some debate concerning whether Truman attempted—in what is called ‘‘atomic diplomacy’’—to use the American nuclear monopoly to cow Stalin into concessions regarding eastern Europe. Regardless of whether this was Truman’s intention, the Soviets certainly believed that the Americans were trying to frighten them, and they were determined to resist. Rejecting the Baruch Plan, an American proposal to bring atomic weapons under international control, Stalin ordered his scientists to build their own bomb as quickly as possible, and gave them all the resources and intellectual freedom necessary to do so.
They succeeded within four years. In August 1949 the Soviet Union conducted its first nuclear test. The intelligence that the Soviet spies had gathered certainly accelerated the development of the Soviet bomb, but it was by no means essential. The scientists working on the project, led by the physicist Igor Kurchatov (1903–1960) and overseen by Lavrenty Beria (1899–1953), the former head of the NKVD (People’s Commissariat of Internal Affairs), were among the world’s best and, in all likelihood, they would eventually have succeeded in building the bomb on their own. The infiltration of the Manhattan Project, as dramatic as it was, only saved the Soviets a few years of work. Nevertheless, the 1949 test was a huge surprise to the United States, which had expected to enjoy its monopoly until at least the early 1950s.