How did the United states react to the Soviet Union exploding its first atomic bomb?

The first successful test of an atomic bomb in the Soviet Union occurred in 1949. This caused great fear and consternation in the United States, as most experts believed the Soviets lagged far behind the Americans in atomic expertise. Fears were intensified when it was discovered that spies within the Manhattan Project, notably Klaus Fuchs, had passed atomic secrets to the Soviets that greatly sped up their efforts. So the explosion of the bomb, along with the victory of Communist revolutionaries led by Mao Zedong in China in the same year, contributed to American fears that the nation was losing the global struggle against Communism. This gave rise to the Second Red Scare, a period of intense anti-Communist hysteria. But perhaps more importantly, it convinced American policy-makers that the nation needed to commit more resources to building a military that could counter the Soviet threat. This commitment was embodied by NSC-68, a memo from the National Security Council to President Truman emphasizing the threat posed by the Soviets, and recommending that the nation be placed, essentially, on a war footing. It began a nuclear "arms race" that would only intensify during the Eisenhower Administration.