In September 1949, the Soviet Union detonated its own atomic bomb. Truman then approved the development of a hydrogen bomb — equivalent to five hundred atomic bombs — rejecting the counterarguments of several scientists who had worked on the atomic bomb and of George Kennan, who warned of an endless arms race. The “superbomb” was ready by 1954, but the U.S. advantage was brief. In November 1955, the Soviets exploded their own hydrogen bomb.

From the 1950s through the 1980s, deterrence formed the basis of American nuclear strategy. To deter a Soviet attack, the United States strove to maintain a nuclear force more powerful than that of the Soviets. Because the Russians pursued a similar policy, the superpowers became locked in an ever-escalating nuclear weapons race. Albert Einstein, whose mathematical discoveries had laid the foundations for nuclear weapons, commented grimly that the war that came after World War III would “be fought with sticks and stones.”

Implementing the second component of containment, the United States beefed up its conventional military power to deter Soviet threats that might not warrant nuclear retaliation. The National Security Act of 1947 united the military branches under a single secretary of defense and created the National Security Council (NSC) to advise the president. During the Berlin crisis in 1948, Congress hiked military appropriations and enacted a peacetime draft. In addition, Congress granted permanent status to the women’s military branches, though it limited their numbers and rank. With 1.5 million men and women in uniform in 1950, the military strength of the United States had quadrupled since the 1930s, and defense expenditures claimed one-third of the federal budget.

Collective security, the third prong of containment strategy, marked a sharp reversal of the nation’s traditional foreign policy. In 1949, the United States joined Canada and Western European nations in its first peacetime military alliance, the North Atlantic Treaty Organization (NATO), designed to counter a Soviet threat to Western Europe (see Map 26.1). For the first time in its history, the United States pledged to go to war if one of its allies was attacked.

The fourth element of defense strategy involved foreign assistance programs to strengthen friendly countries, such as aid to Greece and Turkey and the Marshall Plan. In addition, in 1949 Congress approved $1 billion of military aid to its NATO allies, and the government began economic assistance to nations in other parts of the world.

The fifth ingredient of containment improved the government’s espionage. The National Security Act of 1947 created the Central Intelligence Agency (CIA) to gather information and to perform any activities “related to intelligence affecting the national security” that the NSC might authorize. Such functions included propaganda, sabotage, economic warfare, and support for “anti-communistelements in threatened countries of the free world.” In 1948, secret CIA operations helped defeat Italy’s Communist Party. Subsequently, CIA agents would intervene even more actively, helping to topple legitimate foreign governments and violating the rights of U.S. citizens.

Finally, the U.S. government sought, through cultural exchanges and propaganda, to win “hearts and minds” throughout the world. Truman expanded the Voice of America, created during World War II to broadcast U.S. propaganda abroad. In addition, the State Department sent books, exhibits, jazz musicians, and other performers to foreign countries as “cultural ambassadors.”

By 1950, the United States had abandoned age-old tenets of foreign policy. Isolationism and neutrality had given way to a peacetime military alliance and efforts to control events far beyond U.S. borders. Short of war, the United States could not stop the descent of the iron curtain, but it aggressively and successfully promoted economic recovery and a military shield for the rest of Europe.