In September 1949, President Truman announced that the Soviet Union had successfully detonated an atomic bomb. Four months later, President Truman advised the Atomic Energy Commission to proceed with the development of a hydrogen bomb.
U.S. government officials had predicted that it would take the Soviet Union as long as a decade to develop an atomic bomb. The speed with which the Soviets produced a bomb led to charges that development of the device was a product of Soviet espionage.
The United States set off its first hydrogen bomb in 1953, and the Soviet Union tested its first bomb in 1955.
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