AP US History Exam: Period 8 Notes (1945-1980)

Six Things to Know about AP US History Period 8

  1. The United States positioned itself as a global leader. The Cold War, an escalating struggle between the United States and the Soviet Union, defined this period. Fearing the expansion of communism, the United States got involved in two major military engagements in Korea and Vietnam.
  2. Initially, there was major American support for an anticommunist foreign policy. As the war in Vietnam dragged on, however, mass antiwar protests broke out across the United States. Passionate debates over war in southeast Asia, the proliferation of nuclear weapons, and the power of the executive branch were all central to the politics of this period.
  3. Civil rights activists energized a new nationwide movement for racial progress. Martin Luther King Jr. used the strategies of nonviolent protests, direct action, and legal battles. The landmark Supreme Court case of Brown v. Board of Education (1954) was a significant achievement for civil rights activists, but progress was slow and resistance was high.
  4. Spurred by the civil rights movement, other social movements advocated their causes. Debates raged over issues such as sexuality, gender, the environment, and economic equality, and the counterculture of the 1960s emerged.
  5. In the 1960s, President Johnson’s Great Society program attempted to use the power of the federal government to eliminate poverty, end racial discrimination, and promote social justice. Fearing a cultural and moral decline, conservatives challenged such actions and sought to limit the role of the federal government.
  6. In the 1970s, the public grew increasingly distrustful of the government’s ability to solve problems. This distrust reached a peak with the Watergate scandal, the stalemate in Vietnam, and President Nixon’s resignation from office.


Key Topics–Period 8: 1945 to 1980


Remember that the AP US History exam tests you on the depth of your knowledge, not just your ability to recall facts. While we have provided brief definitions here, you will need to know these terms in even more depth for the AP US History exam, including how terms connect to broader historical themes and understandings.

The Truman Administrations

  • Harry S. Truman: Thirty-third President. Served 1945–1953. Desegregated the U.S. military. Help found the United Nations and pushed for the Marshall Plan. Reformed U.S. foreign policy toward internationalism, with a focus on containment of communism. Oversaw early Cold War conflicts, like the Berlin Airlift and the Korean War. Ordered the use of atomic weapons on the cities of Hiroshima and Nagasaki. Narrowly won reelection in a 1952 upset.
  • George Marshall: Former Army Chief of Staff (1939–1945). Secretary of State (1947–1949) and Secretary of Defense (1950–1951) under Truman. A five-star general, he is credited with the Marshall Plan, a foreign aid package that helped Western Europe rebuild after World War II.
  • Marshall Plan: A program proposed by George Marshall in 1947. Supplied $13 billion to Western Europe, enabling its postwar economic boom and ending the threat of mass starvation.
  • Berlin Airlift: A major crisis in the early Cold War. From June 1948 to May 1949, the Soviet Union blockaded the West’s land access to Berlin. President Truman responded by airlifting in supplies around the clock, putting the onus for starting WWIII on the Soviets.
  • North Atlantic Treaty Organization (NATO): A military alliance formed by the Western Allies of World War II to deter Soviet aggression. It guarantees collective defense under the rule that an attack on one member is an attack on all members.
  • Warsaw Pact: A collective defense arrangement similar to NATO, to protect the Eastern bloc from Western aggression. It also served to solidify Soviet control over Eastern Europe. Dissolved in 1991.
  • National Security Act: A landmark 1947 act that restructured the U.S. government’s military and national security agencies. Established the National Security Council, the Central Intelligence Agency, the Department of Defense, and an independent U.S. Air Force.
  • Department of Defense: Formerly known as the War Department, it was reorganized by the National Security Act of 1947 into the DoD. A cabinet-level office. Military officers are forbidden from serving as the Secretary of Defense until seven years after their retirement, barring a waiver from Congress, in order to ensure civilian control over the military.
  • National Security Council: It coordinates national security and foreign policy among multiple agencies and departments. It also advises the President. Its membership includes the Secretaries of Defense, Energy, and State; the Joint Chiefs of Staff; and other advisors.
  • Central Intelligence Agency (CIA): The CIA is a foreign intelligence service founded in 1947. It is the successor of the Office of Strategic Services (OSS). In the mid 1970s, the Church Committee investigated the CIA for a string of abuses; as a result, the Senate Select Committee on Intelligence was formed to oversee the CIA.


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