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The Cold War (1945–1963)


The Start of the Cold War: 1947–1952

Summary The Start of the Cold War: 1947–1952


  • 1938

    House Un-American Activities Committee created

  • 1947

    Doctrine of containment emerges

    Truman articulates Truman DoctrineCongress passes National Security Act
  • 1948

    Alger Hiss accused of being a Soviet operative

    Truman is reelected
  • 1949

    NATO is formed

    China falls to Communist forces
  • 1950

    Congress passes McCarran Internal Security Bill

  • 1951

    Julius and Ethel Rosenberg convicted of espionage

  • 1952

    United States develops first hydrogen bomb

    • Key People

    • Harry S Truman

      33rd U.S. president; announced Truman Doctrine in 1947, which shaped U.S. foreign policy for four decades

    • Thomas E. Dewey

      New York governor who ran unsuccessfully on the Republican Party ticket against Truman in 1948

    • George F. Kennan

      State Department analyst who developed containment doctrine in 1947, arguing that Communism and the USSR could not be allowed to spread; this doctrine became the basis of U.S. foreign policy strategy during the Cold War

    • Richard M. Nixon

      Republican congressman and prominent member of HUAC in the late 1940s; successfully prosecuted Alger Hiss for being a Communist

    • Alger Hiss

      Former federal employee prosecuted by HUAC in 19481950 for being a Communist and Soviet spy

    • Julius and Ethel Rosenberg

      Married couple convicted of espionage in 1951 after being wrongfully convicted of selling nuclear secrets to the USSR; executed in 1953

    • Chiang Kai-shek

      Leader of China’s Nationalist government when Communist forces drove it out of mainland China in 1949

    • Mao Zedong

      Leader of Communist revolutionaries who brought down China’s Nationalist government in 1949; became ruler of People’s Republic of China as leader of Chinese Communist Party


    In 1947, State Department analyst George F. Kennan penned a highly influential essay on the Soviet Union that transformed fear of the USSR into a cohesive foreign policy. Arguing that insecure Russians had always had the desire to expand and acquire territory, Kennan wrote that the Soviet Union would take every opportunity to spread Communism into every possible “nook and cranny” around the globe, either by conquering neighboring countries or by subtly supporting Communist revolutionaries in politically unstable countries. Kennan also wrote, however, that the United States could prevent the global domination of Communism with a strategy of “containment. He suggested maintaining the status quo by thwarting Communist aggression abroad.

    Kennan’s containment doctrine rapidly became the root of the dominant U.S. strategy for fighting Communism throughout the Cold War. Different presidents interpreted the doctrine differently and/or employed different tactics to accomplish their goals, but the overall strategy for keeping Communism in check remained the same until the Cold War ended in the early 1990s.

    The Truman Doctrine

    Truman quickly latched onto the doctrine of containment and modified it with his own Truman Doctrine. In a special address to Congress in March 1947, Truman announced that the United States would support foreign governments resisting “armed minorities” or “outside pressures”—that is, Communist revolutionaries or the Soviet Union. He then convinced Congress to appropriate $400 million to prevent the fall of Greece and Turkey to Communist insurgents.

    Critics, both at the time and looking back in retrospect, have charged that Truman’s adoption of the containment doctrine, coupled with his own Truman Doctrine, accelerated the Cold War by polarizing the United States and the USSR unnecessarily. Many have claimed that the United States might have avoided fifty years of competition and mutual distrust had Truman sought a diplomatic solution instead.

    Defendants of Truman’s policy, however, have claimed that the Soviet Union had already begun the Cold War by thwarting Allied attempts to reunite and stabilize Germany. Truman, they have argued, merely met the existing Soviet challenge. Other supporters believed that Truman used polarizing language in order to prevent U.S. isolationists from abandoning the cause in Europe. Whatever his motivations, Truman’s adoption of the containment doctrine and his characterization of the Communist threat shaped American foreign policy for the subsequent four decades.

    The National Security Act

    The possibility of a war with the Soviet Union prompted Congress, Truman, and the military leadership to drastically reorganize the intelligence-gathering services and armed forces. In 1947, Congress passed the landmark National Security Act, which placed the military under the new cabinet-level secretary of defense. Civilians would be chosen to serve in the post of secretary of defense and as the secretaries of the individual military branches, while the highest-ranking officers in the armed forces would form the new Joint Chiefs of Staff to coordinate military efforts. The National Security Act also created the civilian position of national security advisor to advise the president and direct the new National Security Council. The new Central Intelligence Agency became the primary espionage and intelligence-gathering service.

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