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The Cold War

How the United States contained Soviet power from 1947 to 1991—through aid, alliances, crises and proxy wars.

Practice this skill 25 min The Cold War Leer en español
Key idea

What you'll learn

In plain words: for over 40 years, the U.S. and the Soviet Union competed for power without fighting each other directly.

The Cold War (about 1947–1991) was a long struggle between the United States and the Soviet Union (USSR). It was "cold" because the two superpowers never fought each other directly. Instead, they competed through alliances, an arms race, a space race and wars in other countries. Think of two rival teams that never play each other but fight to sign the best players and win every other game. You will learn:

  • why the Cold War began and what containment meant;
  • the main tools of containment: the Truman Doctrine, the Marshall Plan and NATO;
  • the major crises: Berlin, Korea, Cuba and Vietnam;
  • the arms race, the space race and détente;
  • how the Cold War ended with the fall of the Soviet Union.

The illustrative graph below shows the general pattern of tension, not measured data:

Illustrative line graph, not measured data, of Cold War tension from 1945 to 1991. Tension rises after 1947 and is high during the Berlin Airlift, peaks at the Cuban Missile Crisis in 1962, falls during détente in the 1970s (SALT I, 1972), rises again with the military buildup of the early 1980s, then falls steeply until the Soviet Union ends in December 1991.Cold War Tension Over Time (illustrative, not measured data)19501960197019801990tension (low → high)détente(SALT I, 1972)BerlinAirliftCuban MissileCrisis 19621980sbuildupUSSR endsDec. 1991

How it shows up on the GED: Cold War questions often use:

  • presidential speeches (Truman, Eisenhower, Kennedy, Reagan);
  • maps of divided Europe or Berlin;
  • timelines and graphs (such as U.S. troop levels in Vietnam).

You may be asked to identify a policy, explain a cause or effect, or interpret a phrase. You may also connect an event to a principle like war powers.

Words to know

Key terms

  • superpower — a nation with enormous military and economic power (the U.S. and USSR after 1945).
  • communism — a system in which the state owns property and one party rules (the Soviet Union).
  • capitalism — an economic system based on private ownership and free markets (the United States).
  • Iron Curtain — the line dividing communist Eastern Europe from democratic Western Europe.
  • containment — the U.S. policy of stopping the spread of communism to new countries.
  • satellite state — a country controlled by a more powerful one (Poland under Soviet control).
  • NATO — the North Atlantic Treaty Organization (1949), a U.S.-led military alliance.
  • Warsaw Pact — the Soviet-led military alliance (1955).
  • arms race — competition to build more and better weapons, especially nuclear weapons.
  • deterrence — preventing an attack by threatening a devastating response.
  • domino theory — the belief that if one country fell to communism, its neighbors would follow.
  • proxy war — a war in which superpowers back opposing sides without fighting each other directly (Vietnam).
  • détente — the easing of Cold War tensions in the 1970s (SALT I, 1972).
  • McCarthyism — the early-1950s practice of making unproven accusations of communist disloyalty.

All Social Studies words in the glossary

1. How the Cold War began and the policy of containment

Timeline of the Cold War, 1945 to 1991: 1947 Truman Doctrine and Marshall Plan; 1948-1949 Berlin Airlift; 1949 NATO formed; 1950-1953 Korean War; 1957 Sputnik launched by the Soviet Union; 1961 Berlin Wall built; 1962 Cuban Missile Crisis; 1969 Apollo 11 Moon landing; 1972 SALT I arms treaty (detente); 1989 Berlin Wall falls; 1991 Soviet Union dissolves. The Cold War, 1945–1991 1947 Truman Doctrine 1948–49 Berlin Airlift 1949 NATO formed 1950–53 Korean War 1957 Sputnik 1961 Berlin Wall built 1962 Cuban Missile Crisis 1969 Moon landing 1972 SALT I (détente) 1989 Berlin Wall falls 1991 USSR dissolves

In plain words: after World War II, the U.S. tried to stop communism from spreading by sending aid and forming an alliance.

The U.S. and USSR were allies against Nazi Germany. But they had opposite systems and goals. After 1945, the Soviet Union kept its army in Eastern Europe. It installed communist governments there. Winston Churchill called the dividing line an "iron curtain" across Europe. U.S. diplomat George Kennan argued that the United States should contain Soviet expansion — keep it from spreading, the way you contain a fire. Three tools put containment into action:

PolicyYearWhat it did
Truman Doctrine1947$400 million in aid to Greece and Turkey; pledged to "support free peoples" resisting takeover
Marshall Plan1948–1952about $13 billion in economic aid to rebuild Western Europe
NATO1949military alliance: an attack on one member is an attack on all (Article 5)
Diagram of containment, the policy of keeping Soviet communism from spreading, as argued by George Kennan. Three tools branch from it. Truman Doctrine, 1947: 400 million dollars in aid to Greece and Turkey (political and military aid). Marshall Plan, 1948 to 1952: about 13 billion dollars to rebuild Western Europe (economic aid). NATO, 1949: a military alliance in which an attack on one member is an attack on all, Article 5.Containment: Three Tools (1947–1949)CONTAINMENTkeep Soviet communism from spreading(George Kennan)Truman Doctrine, 1947400 million dollarsin aid to Greeceand Turkeypolitical / military aidMarshall Plan, 1948–1952about 13 billiondollars to rebuildWestern Europeeconomic aidNATO, 1949military alliance:an attack on one isan attack on all (Art. 5)military alliance

Example: A source describes sending money to rebuild farms and factories in France. It is describing the Marshall Plan, not NATO.

The two military alliances that faced each other across Europe:

Schematic diagram, not to scale, of the two Cold War alliances, divided in Europe by the Iron Curtain. West: NATO, formed in 1949 and led by the United States; 12 founders were the United States, Canada, Britain, France, Italy, Belgium, the Netherlands, Luxembourg, Norway, Denmark, Iceland and Portugal; Greece and Turkey joined in 1952 and West Germany in 1955. East: the Warsaw Pact, formed in 1955 and led by the Soviet Union, with Poland, East Germany, Czechoslovakia, Hungary, Romania, Bulgaria and Albania; these satellite states had communist governments installed after 1945.Two Cold War Alliances (schematic, not to scale)NATO (1949)led by the United StatesUnited States, Canada,Britain, France, Italy,Belgium, Netherlands,Luxembourg, Norway,Denmark, Iceland, Portugal(12 founders)joined later: Greece andTurkey (1952), West Germany (1955)WARSAW PACT (1955)led by the Soviet UnionSoviet Union, Poland,East Germany,Czechoslovakia, Hungary,Romania, Bulgaria,Albaniacommunist governmentsinstalled after 1945(satellite states)the "Iron Curtain"West (capitalism, U.S. allies) | East (communism, Soviet control)

2. Berlin and Korea

Schematic map of divided Germany, 1949 to 1990. West Germany, allied with the United States, is on the left. East Germany, controlled by the Soviet Union, is on the right, separated by a fortified border that was part of the Iron Curtain. The city of Berlin lies deep inside East Germany, about 100 miles from the border. Berlin is split into a western half (the U.S., British and French sectors, called West Berlin) and an eastern half (the Soviet sector, East Berlin). Poland lies east of East Germany. Divided Germany and Berlin, 1949–1990 (schematic) WEST GERMANY (allied with U.S.) EAST GERMANY (Soviet-controlled) Border (part of the Iron Curtain) West East BERLIN West: U.S., British, French sectors East: Soviet sector POLAND

In plain words: early Cold War crises in Berlin and Korea tested whether the U.S. would stand firm.

Berlin:

  • Germany and its capital, Berlin, were divided among the Allies.
  • In 1948 the Soviets blockaded West Berlin — they cut off roads and railways. The U.S. and Britain answered with the Berlin Airlift (1948–1949), flying in supplies.
  • In 1949 Germany split into West Germany and East Germany.
  • In 1961 East Germany built the Berlin Wall. It became the symbol of the Cold War until it fell on November 9, 1989.

1949, a turning point: the Soviet Union tested its first atomic bomb. And Mao Zedong's communists won China's civil war. Fear of communism at home fed the Red Scare and McCarthyism.

Korea (1950–1953): Korea had been divided at the 38th parallel. In June 1950, communist North Korea invaded South Korea. A United Nations force led by the U.S. pushed back. China then entered on the North's side. An armistice in 1953 left Korea divided near the 38th parallel. It remains divided today. About 36,000 Americans died. Korea was the first major test of containment by force.

3. Arms race, space race and Cuba

In plain words: both sides built huge numbers of nuclear weapons and raced into space, and in 1962 they came close to nuclear war over Cuba.

Both sides built thousands of nuclear weapons. The idea of deterrence — preventing an attack by threatening a devastating response — kept the peace. It was later called "mutually assured destruction." Neither side would attack, because both would be destroyed. In his 1961 farewell address, President Eisenhower warned that Americans "must guard against the acquisition of unwarranted influence … by the military-industrial complex."

Space race:

  • The Soviet launch of Sputnik (1957) shocked Americans.
  • Congress created NASA (1958) and funded science education.
  • In 1961, Kennedy set the goal "of landing a man on the moon and returning him safely to the earth."
  • Apollo 11 achieved it in July 1969.
Timeline of the space race, 1957 to 1969: October 1957, the Soviet Union launches Sputnik; 1958, Congress creates NASA; May 1961, Kennedy sets the goal of landing a man on the Moon; July 1969, Apollo 11 lands on the Moon. Red marks the Soviet achievement; blue marks the U.S. response.The Space Race, 1957–196919561958196019621964196619681970Oct. 1957Soviet Unionlaunches Sputnik1958Congresscreates NASAMay 1961Kennedy sets theMoon-landing goalJuly 1969Apollo 11 landson the MoonRed = Soviet achievementBlue = U.S. response

Cuba:

  • After Fidel Castro's 1959 revolution, Cuba allied with the USSR.
  • The CIA-backed Bay of Pigs invasion by Cuban exiles failed (1961).
  • In October 1962, the Cuban Missile Crisis brought the world close to nuclear war. Kennedy ordered a naval "quarantine." The Soviets removed their missiles.
  • Afterward, a hotline linked Washington and Moscow. The Limited Test Ban Treaty (1963) banned nuclear tests in the atmosphere.
Cause and effect chain for Cuba in the Cold War. 1959: Fidel Castro's revolution; Cuba allies with the Soviet Union. April 1961: the CIA-backed Bay of Pigs invasion fails. October 1962: Soviet missiles are found in Cuba and Kennedy orders a naval quarantine. October 28, 1962: the Soviets agree to remove the missiles. 1963: a Washington–Moscow hotline is set up and the Limited Test Ban Treaty is signed. This was the closest the superpowers came to nuclear war; afterward both sides took steps to lower the risk.Cuba and the Cold War: Cause and Effect1959Castro's revolution;Cuba allies withthe USSRApril 1961CIA-backed Bayof Pigs invasionfailsOctober 1962Soviet missiles found;Kennedy orders anaval "quarantine"Oct. 28, 1962Soviets agree toremove themissiles1963Washington–Moscowhotline; LimitedTest Ban TreatyClosest the superpowers came to nuclear warAfter the crisis, both sides took steps to lower the risk.

4. Vietnam

Bar chart: U.S. military personnel in South Vietnam at the end of each year, in thousands (rounded). 1964: 23; 1965: 184; 1966: 385; 1967: 486; 1968: 536; 1969: 475; 1970: 335; 1971: 157; 1972: 24. Source: U.S. Department of Defense. U.S. Troops in Vietnam (end of year) 0 100 200 300 400 500 600 Troops (thousands) 23 1964 184 1965 385 1966 486 1967 536 1968 475 1969 335 1970 157 1971 24 1972

In plain words: fearing that communism would spread country by country, the U.S. fought a long war in Vietnam.

The domino theory said that if one country fell to communism, its neighbors would follow. Following this idea, the U.S. supported non-communist South Vietnam. It fought communist North Vietnam and the Viet Cong.

Diagram of the domino theory stated by Eisenhower in 1954. A row of dominoes is labelled Vietnam, Laos, Cambodia, Thailand and next?. The first domino, Vietnam, is tipping into the second. Caption: if one country falls to communism, the theory said, its neighbors would fall one after another; this belief led the U.S. to fight in Vietnam.The Domino Theory (1954)VietnamLaosCambodiaThailandnext?one country falls to communism …… so, the theory said, its neighbors would fall one after another.This belief led the U.S. to fight in Vietnam.
  • After the Gulf of Tonkin Resolution (1964), President Johnson sent hundreds of thousands of troops. They peaked at over 500,000.
  • The Tet Offensive (1968) turned many Americans against the war, and protests grew.
  • Nixon's Vietnamization brought troops home. A peace agreement came in 1973. Saigon fell in 1975.
  • About 58,000 Americans died.

In response, Congress passed the War Powers Resolution (1973). It limits a president's ability to wage war without congressional approval.

Example: A graph shows troops rising from 23,000 (1964) to 536,000 (1968), then falling after 1969. This reflects escalation under Johnson and withdrawal under Nixon.

5. Détente and the end of the Cold War

In plain words: tensions eased in the 1970s, rose again, and ended when the Soviet Union broke apart in 1991.

  • Détente (1970s): détente means an easing of tensions. Nixon visited China (1972). He also signed the SALT I arms-limitation treaty with the USSR (1972).
  • Renewed tension: the Soviet invasion of Afghanistan (1979) ended détente. President Reagan increased military spending in the 1980s.
  • Reform and collapse: Soviet leader Mikhail Gorbachev introduced glasnost (openness) and perestroika (economic restructuring). In Berlin in 1987, Reagan challenged him: "Mr. Gorbachev, tear down this wall!" The two leaders signed the INF Treaty (1987). It eliminated a whole class of nuclear missiles.
  • 1989–1991: revolutions swept Eastern Europe. The Berlin Wall fell (1989). Germany reunited (1990). The Soviet Union dissolved in December 1991 into 15 independent countries. The United States became the world's only superpower.
Cause and effect chain showing how the Cold War ended. From 1985: Soviet leader Gorbachev introduces glasnost (openness) and perestroika (restructuring). 1987: Reagan says tear down this wall, and the INF Treaty is signed. 1989: revolutions sweep Eastern Europe and the Berlin Wall falls. 1990: Germany reunites. December 1991: the Soviet Union dissolves into 15 countries. Result: the United States is the world's only superpower. Note: the Berlin Wall stood from 1961 to November 9, 1989.How the Cold War Ended1985 onGorbachev:glasnost andperestroika1987Reagan: "Tear downthis wall!"; INFTreaty signed1989revolutions inEastern Europe;Berlin Wall falls1990GermanyreunitesDec. 1991Soviet Uniondissolves into 15countriesResult: the United States is the world's only superpower.The Berlin Wall stood from 1961 to November 9, 1989.
Worked example

Worked example 1: Identifying a policy from a source

Source: "I believe that our help should be primarily through economic and financial aid which is essential to economic stability and orderly political processes." (Truman, 1947)

Question: This statement reflects which strategy? A. isolationism B. containment through economic support C. détente D. massive military invasion

Think-aloud:

  1. Date 1947 and speaker Truman → early Cold War.
  2. "Economic and financial aid" to prevent instability → strengthening countries so communism cannot spread.
  3. A means staying out, but Truman is getting involved. C is the 1970s. D contradicts "economic" aid.
  4. Answer: B.
Worked example

Worked example 2: Reading the Vietnam troop graph

Bar chart: U.S. military personnel in South Vietnam at the end of each year, in thousands (rounded). 1964: 23; 1965: 184; 1966: 385; 1967: 486; 1968: 536; 1969: 475; 1970: 335; 1971: 157; 1972: 24. Source: U.S. Department of Defense. U.S. Troops in Vietnam (end of year) 0 100 200 300 400 500 600 Troops (thousands) 23 1964 184 1965 385 1966 486 1967 536 1968 475 1969 335 1970 157 1971 24 1972

Question: By about how many troops did the U.S. force in Vietnam decrease from the end of 1969 to the end of 1971? A. 157,000 B. 318,000 C. 379,000 D. 475,000

Think-aloud:

  1. Read the bars: 1969 = 475 thousand; 1971 = 157 thousand.
  2. Subtract: 475 − 157 = 318 thousand.
  3. A is the 1971 value alone; D is the 1969 value alone. C (536 − 157 = 379) uses the wrong starting year.
  4. Answer: B, about 318,000.
Worked example

Worked example 3: Interpreting a metaphor

Source: "You have a row of dominoes set up, you knock over the first one, and what will happen to the last one is the certainty that it will go over very quickly." (Eisenhower, 1954)

Question: Eisenhower used this image to argue that A. the U.S. should leave Southeast Asia B. the fall of one country to communism could cause its neighbors to fall C. the Soviet Union was about to collapse D. games build alliances

Think-aloud:

  1. Dominoes = countries; knocking over = falling to communism.
  2. One falling causes the next to fall → a chain reaction.
  3. A is the opposite of the argument; C is 1991; D is literal.
  4. Answer: B—the domino theory.
Worked example

Worked example 4: Map plus text

Schematic map of divided Germany, 1949 to 1990. West Germany, allied with the United States, is on the left. East Germany, controlled by the Soviet Union, is on the right, separated by a fortified border that was part of the Iron Curtain. The city of Berlin lies deep inside East Germany, about 100 miles from the border. Berlin is split into a western half (the U.S., British and French sectors, called West Berlin) and an eastern half (the Soviet sector, East Berlin). Poland lies east of East Germany. Divided Germany and Berlin, 1949–1990 (schematic) WEST GERMANY (allied with U.S.) EAST GERMANY (Soviet-controlled) Border (part of the Iron Curtain) West East BERLIN West: U.S., British, French sectors East: Soviet sector POLAND

Source: the map of divided Germany, plus the sentence "In 1961, East Germany built the Berlin Wall to stop its people from escaping to the West."

Question: Why could East Germans escape most easily in Berlin before 1961? A. Berlin was on the coast B. West Berlin was an open, Western-controlled area inside East Germany C. the Soviets controlled all of Berlin D. West Germany surrounded Berlin

Think-aloud:

  1. On the map, West Berlin is a Western-controlled area surrounded by East Germany.
  2. Crossing from East Berlin to West Berlin was as easy as crossing a street. Then the wall went up.
  3. A, C and D misread the map.
  4. Answer: B.
Common mistake

Common traps

  • Mixing up the Truman Doctrine and the Marshall Plan. Truman Doctrine = aid to Greece and Turkey (1947). Marshall Plan = economic recovery for Western Europe (1948–1952).
  • Thinking the U.S. and USSR fought each other directly. They fought proxy wars (Korea, Vietnam) and competed in arms and space.
  • Confusing détente with deterrence. Deterrence = threats to prevent attack. Détente = easing tensions (1970s).
  • Assuming the Gulf of Tonkin Resolution was a declaration of war. It gave the president broad authority. Congress never declared war in Vietnam.
  • Placing the Berlin Wall at the start of the Cold War. The wall went up in 1961 and fell in 1989. The airlift (1948–1949) came first.
  • Reading only the everyday meaning of a word. Kennedy's "quarantine" meant a naval blockade of weapons.
Test strategy

GED strategy for Cold War questions

  • Place the source in time. 1940s = containment begins; 1950s = Korea, arms race, Sputnik; 1960s = Cuba, Vietnam, Moon; 1970s = détente; 1980s–1991 = end.
  • Name the strategy. Ask: Is this aid, alliance, deterrence, a proxy war or détente?
  • Use the italic introduction to identify places and people the speaker only hints at ("that imprisoned island" = Cuba).
  • On graphs, read every bar you need and do the subtraction. Wrong choices often use a single bar's value.
  • Watch for civics links: war powers (Congress declares war), the War Powers Resolution, treaties approved by the Senate.
  • Eliminate wrong-era choices quickly. Many wrong choices describe a real event from a different decade.

Check yourself

The Cold War
The Truman Doctrine (1947)

After World War II, the Soviet Union set up communist governments across Eastern Europe. In 1947, Britain told the United States it could no longer afford to support the governments of Greece, which was fighting communist-led rebels, and Turkey, which faced Soviet pressure. On March 12, 1947, President Harry S. Truman asked Congress for $400 million in aid for the two countries.

(1) At the present moment in world history nearly every nation must choose between alternative ways of life. …

(2) I believe that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.

(3) I believe that we must assist free peoples to work out their own destinies in their own way.

(4) I believe that our help should be primarily through economic and financial aid which is essential to economic stability and orderly political processes.

Which statement best summarizes the policy Truman describes in paragraph 2?

Answer choices
Hint

Paragraph 2 begins "it must be the policy of the United States to …" Restate the rest in your own words.

Check yourself

The Cold War
The Truman Doctrine (1947)

After World War II, the Soviet Union set up communist governments across Eastern Europe. In 1947, Britain told the United States it could no longer afford to support the governments of Greece, which was fighting communist-led rebels, and Turkey, which faced Soviet pressure. On March 12, 1947, President Harry S. Truman asked Congress for $400 million in aid for the two countries.

(1) At the present moment in world history nearly every nation must choose between alternative ways of life. …

(2) I believe that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.

(3) I believe that we must assist free peoples to work out their own destinies in their own way.

(4) I believe that our help should be primarily through economic and financial aid which is essential to economic stability and orderly political processes.

According to paragraph 4, what kind of help did Truman think the United States should mainly provide?

Answer choices
Hint

Find the word "primarily" in paragraph 4.

Summary

  • The Cold War (1947–1991) pitted the U.S. and its allies against the Soviet Union and its satellites. The superpowers never fought a direct war.
  • Containment was carried out through the Truman Doctrine (1947), the Marshall Plan (1948–1952) and NATO (1949).
  • Crises included the Berlin Airlift (1948–1949), the Korean War (1950–1953), the Berlin Wall (1961) and the Cuban Missile Crisis (1962).
  • The domino theory drew the U.S. into Vietnam. In response to the war, Congress passed the War Powers Resolution (1973).
  • The arms and space races (Sputnik 1957, Apollo 11 1969) were followed by détente in the 1970s (SALT I).
  • Gorbachev's reforms, the fall of the Berlin Wall (1989) and the Soviet collapse (1991) ended the Cold War.
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