How did NSC 68 differ from the original policy of containment
Two events in 1949 shocked many Americans and worsened Cold War tensions. First, the USSR tested its first atomic bomb. Second, China became a communist nation following the victory of Mao Zedung's communist rebels. These events combined to lead many Americans to fear that communism was rapidly gaining power around the globe. Some Americans suspected that the USSR could not have developed an atomic bomb so quickly without help from communist spies in the U.S. Also, critics blamed the Truman administration for "losing" China by not doing more to stop the Chinese revolution.
In 1950, the Truman administration responded to the events of 1949 by developing a new Cold War policy. Truman announced that the U.S. would develop a hydrogen bomb (many times more destructive than an atomic bomb). The United States first tested a hydrogen bomb in 1952, and the Soviet Union tested its own hydrogen bomb in 1953. The administration also drafted a new Cold War strategy, known as NSC 68 (named for National Security Council report number 68). NSC 68 (a top secret document at the time) was based on the so-called domino theory, the belief that communist victories in one nation inevitably endangered that nation's neighbors. Like the Truman Doctrine, NSC 68 committed the U.S. to containment of communism around the globe. The new policy suggested that the USSR was likely to go to war to further its goal of world domination, and urged the U.S. to increase its own military spending (raising it from 13 billion dollars per year to 50 billion). So, NSC 68 relied on military strength, not diplomacy, to resist communism.