Period 8 Cold War America (1945–1980): Foreign Policy, Fear at Home, and Vietnam

Cold War

Decades-long struggle for global power and influence after World War II between the United States and the Soviet Union, fought through competition rather than direct full-scale war between their armies.

Proxy war

A conflict in which major powers (like the U.S. and USSR) support opposing local forces instead of fighting each other directly.

Containment

Core U.S. Cold War strategy to prevent Soviet expansion and the spread of new communist governments, usually by defending key “lines” rather than rolling back communism everywhere.

Truman Doctrine

1947 U.S. policy to support “free peoples” resisting subjugation (often meaning communism), first applied through aid to Greece and Turkey; signaled long-term U.S. global involvement.

Marshall Plan (European Recovery Program)

U.S. program proposed in 1947 and enacted in 1948 that provided major economic aid to rebuild Western Europe to reduce instability and communist appeal while creating markets for U.S. goods.

Berlin Airlift

1948–1949 U.S.-allied operation supplying West Berlin by air in response to the Soviet blockade, showing intense confrontation calibrated to avoid direct war.

NATO

North Atlantic Treaty Organization (formed 1949), a collective security alliance of the U.S., Canada, and Western European nations to deter Soviet aggression.

NSC-68

1950 U.S. policy paper that argued the Soviet threat required a major military buildup, helping intensify and militarize containment.

Korean War

1950–1953 war that began when North Korea invaded South Korea; the U.S. fought under a UN banner to defend the South, and China entered on the North’s side after UN/U.S. forces neared its border.

Armistice (Korea, 1953)

The agreement that ended major fighting in the Korean War without a peace treaty, leaving Korea divided roughly near the 38th parallel.

Brinkmanship

Cold War tactic of pushing crises to the edge of war to force an opponent to back down, relying on the threat and psychology of potential escalation.

Cuban Missile Crisis

1962 confrontation sparked by Soviet nuclear missiles in Cuba; the closest the Cold War came to nuclear war, resolved through a U.S. naval “quarantine” and negotiated Soviet withdrawal.

Détente

Late 1960s–1970s policy of relaxing and managing Cold War tensions with the USSR and China to reduce nuclear-war risk without ending rivalry.

Soviet invasion of Afghanistan (1979)

Event that intensified Cold War tensions and is often used to mark the end of détente and the start of a more confrontational phase.

Second Red Scare

Late 1940s–1950s period of intense fear of communist infiltration in U.S. institutions, mixing real security concerns with exaggerated accusations and civil-liberties violations.

McCarthyism

Political style associated with Senator Joseph McCarthy involving dramatic accusations of disloyalty without solid evidence, using fear to gain power and attention.

Executive Order 9835

Truman’s 1947 order creating a federal loyalty program to investigate government employees; intended to prevent espionage but often encouraged suspicion and guilt by association.

HUAC (House Un-American Activities Committee)

Congressional committee that investigated alleged communist influence, notably including probes of the entertainment industry.

Blacklisting

Practice (especially in entertainment and other workplaces) of informally denying jobs to people suspected of communist ties, using economic pressure to limit speech without necessarily jailing them.

Domino theory

Cold War belief that if one country fell to communism, nearby countries would follow, shaping U.S. credibility and containment arguments for staying in Vietnam.

Geneva Accords (1954)

Agreements that temporarily divided Vietnam at the 17th parallel and proposed elections for reunification; the U.S. feared elections would bring a communist victory and backed an anti-communist South.

Gulf of Tonkin Resolution

1964 measure passed after the Gulf of Tonkin incident that gave President Johnson broad authority to use force in Southeast Asia, enabling major escalation without a formal war declaration.

Tet Offensive

1968 coordinated attacks by North Vietnamese and Viet Cong forces; not an immediate military win for the attackers, but a major political-psychological blow that undermined U.S. claims victory was near.

Vietnamization

Nixon’s strategy to withdraw U.S. troops while building up South Vietnamese forces, seeking “peace with honor” while trying to maintain leverage.

War Powers Act (1973)

Law passed by Congress to limit presidential power to commit U.S. forces without congressional approval, reflecting Vietnam-era debates over executive authority.