Passing atomic secrets to the Soviet Union by the Rosenbergs threatened the U.S. by removing its atomic weapon monopoly, leading to mutual assured destruction and an arms race.
The passing of atomic secrets to the Soviet Union by the Rosenbergs was a significant threat to the United States because it meant that the United States would no longer be the only nation on earth with control over atomic weapons. This act led to a situation of mutual assured destruction, triggering an arms race between the United States and the Soviet Union. The fear of the Soviets gaining a significant advantage in the size of their nuclear inventory intensified tensions during the Cold War.
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