20th century: International relations since 1919

Why did the USA-USSR alliance begin to break down in 1945?

• wartime alliance was based on a common enemy (Nazi German)

• Capitalism vs. Communism

• Disagreements at Yalta and Potsdam ( Polands future, reparations, Eastern Europe)

• The USAs use of the aromic bomb without informing the USSR

• GBs knowledge of enigma codes not shared with stalin

How had the USSR gained control of Eastern Europe by 1948?

• soviet troops remained in Eastern Europe after WW1

• Set up communist governments (Poland, Hungary)

• Non free elections (rigged)

How did the USA react to soviet expansionism?

• Truman Doctrine (1947) - contain communism

• Marshall Plan (1947) - economic aid to rebuild europe

• NATO (1949) - military alliance to counter soviet threat

Why did Stalin blockade Berlin

• Annoyed about creation of new currency (deutchsemark)

• Wanted to push the western powers out of Berlin

Consequences of Berlin Blockade

• USSR blocked all rail, air and canals, to west Berlin (1928-49)

• USA responded either the berlin airlift supplying necessities in agreed 3×20 mile air corridors

• Heightened tensions

Why was USA to blame for Cold war

• aggressive containment

• Atomic diplomacy

• Economic imperialism

Why was USSR to blame for the cold war

• Expansionism in Eastern Europe

• Imposition of communist regimes

Korean War Background

• After WWII, Korea was divided at the 38th parallel: North Korea (communist, backed by USSR and China) and South Korea (capitalist, supported by USA).

• Tensions escalated as both sides claimed to be the legitimate government of all Korea.

Korean War Key Events

• June 1950: North Korea invaded South Korea, quickly capturing Seoul.

• USA intervened through the UN (Soviet Union was boycotting the UN at the time).

• General Douglas MacArthur led a counter-offensive:

  • Amphibious landing at Inchon turned the tide.

  • Pushed North Koreans back to the Chinese border.

  • China entered the war in October 1950:

    • Pushed UN forces back below the 38th parallel.

    • Bloody stalemate ensued, especially around the 38th parallel.

End of Korean War

• 1953: Armistice signed (not a peace treaty).

• Border remained near original line at the 38th parallel.

Outcome of Korean War

Successes for USA:

• Containment worked: South Korea remained non-communist.

• Showed US commitment to stopping communism globally.

❌ Failures:

• No reunification of Korea.

• High human and financial cost: ~36,000 American troops died.

• Limited public support by the end.

CMC Background

• 1959: Fidel Castro overthrew US-backed dictator Batista.

• Castro aligned with the USSR and nationalised American businesses in Cuba.

• USA saw this as a major threat due to Cuba's proximity (90 miles from Florida).

Bay pf pigs - 1961

• US-backed Cuban exiles attempted to overthrow Castro.

• Failed disastrously, embarrassing the USA and strengthening Castro’s position.

Cuban Missile Crisis- 1962

• US spy planes discovered Soviet nuclear missiles in Cuba.

• President Kennedy imposed a naval blockade ("quarantine") of Cuba.

• 13 tense days followed (October 1962) as the world edged towards nuclear war.

CMC Resolution

• USSR agreed to remove missiles from Cuba.

• USA secretly agreed to remove its missiles from Turkey and not to invade Cuba.

CMC Outcome

• USSR agreed to remove missiles from Cuba.

• USA secretly agreed to remove its missiles from Turkey and not to invade Cuba.

Vietnam War Background

• Vietnam divided after French withdrawal: North (communist) led by Ho Chi Minh, South (non-communist)supported by the USA.

• The US feared the "Domino Theory" – that if Vietnam fell to communism, others in Asia would follow.

Vietnam Key Events

• 1955–63:

  • US supported corrupt South Vietnamese regime under Ngo Dinh Diem.

  • Rising insurgency from Viet Cong (communist guerrillas) in the South.

  • US involvement increased under President Kennedy.

• 1964–68: Escalation under Johnson:

  • Gulf of Tonkin Incident (1964) led to full-scale US military involvement.

  • Operation Rolling Thunder: heavy bombing of North Vietnam.

  • Over 500,000 US troops deployed by 1968.

Korean Tactics

• US: Search-and-destroy missions, napalm, Agent Orange.

• Viet Cong: Guerrilla warfare, use of tunnels, support from locals.

• 1968 – Tet Offensive:

  • Massive Viet Cong surprise attacks during the Vietnamese New Year.

  • US military regained control, but public opinion turned against the war.

Vietnamization - Nixon 1969-73

• Gradual withdrawal of US troops.

• Increased bombing in Cambodia and Laos.

• 1973: Paris Peace Accords signed.

Vietnam Outcome

✅ Successes for USA:

• Delayed the communist takeover for several years.

• Demonstrated strong commitment to containment.

❌ Failures:

• Enormous cost: Over 58,000 US soldiers dead; millions of Vietnamese civilians killed.

• Massive domestic protests in the US.

• Ultimately a failure of containment – Vietnam was united under communism.

Opposition in Hungary (1956) Background

• Post-WWII, Hungary became a Soviet satellite with a communist government.

• People suffered under repression, secret police (ÁVH), and economic hardship.

The Revolt in Hungary

• Inspired by Khrushchev’s “De-Stalinisation” speech.

• Massive demonstrations in Budapest.

• Reformist Imre Nagy became Prime Minister; announced Hungary would leave the Warsaw Pact and become neutral.

Soviet reaction to Hungary revolt

• USSR invaded with 200,000 troops and tanks.

• Thousands killed; Nagy was captured and executed.

• Pro-Soviet János Kádár installed.

✅ Impact: USSR showed it would not tolerate withdrawal from its sphere; strong display of control through military force.

Czechoslovakia 1968 Background

• Growing dissatisfaction with economic problems and lack of freedoms.

• Reformist Alexander Dubček became leader; proposed “Socialism with a human face” (freedom of speech, press, travel).

Soviet reaction to Czechoslovakia

• Brezhnev and Warsaw Pact forces invaded in August 1968.

• No violent resistance, but reforms were rolled back.

• Dubček was removed; replaced by hardliner Husák.

✅ Impact: Showed USSR’s unwillingness to allow liberal reform; led to Brezhnev Doctrine (USSR had the right to intervene in any communist country under threat).

Comparison of Hungary and Czechoslovakia

Why was Berlin Wall built 1961 Background

• Berlin was divided: West Berlin (democratic, capitalist) vs East Berlin (communist).

• Between 1949 and 1961, over 2.5 million East Germans fled to the West through Berlin.

Why was Berlin Wall built 1961 Soviet concerns

• Brain drain: skilled workers, professionals, and youth escaping.

• Economic failure of East Germany (GDR) was being exposed.

Construction of Berlin Wall

• August 1961: East Germany, with Soviet support, built the Berlin Wall overnight.

• Sealed off East Berlin from West Berlin.

• Became a symbol of Cold War division.

✅ Impact: Stopped mass emigration. USSR regained control and stability in East Germany, but it highlighted the failure of communism to satisfy its citizens.

Solidarity 1980 Background

• Economic collapse, food shortages, and rising prices under communist rule.

• Formation of Solidarity, an independent trade union led by Lech Wałęsa, in 1980.

• Grew rapidly, with 10 million members.

Solidarity - Soviet response

• USSR pressured Polish government to act.

• 1981: Polish General Jaruzelski declared martial law; Solidarity banned, leaders arrested.

Significance of Solidarity

• Solidarity survived underground and continued to gain support.

• By 1989, under Gorbachev’s reforms, negotiations led to semi-free elections.

• Solidarity won; first peaceful transfer of power away from communists.

✅ Impact: Major turning point — showed USSR would no longer intervene militarily; inspired movements across Eastern Europe.

Gorbachev key reforms

• Perestroika: Economic restructuring (more openness to market forces).

• Glasnost: Political openness and freedom of expression.

• Rejected the Brezhnev Doctrine – allowed Eastern bloc countries to make their own reforms.

Gorbachev - events

• Weakened Soviet grip; Eastern European countries began reforming independently.

• Uprisings in East Germany, Czechoslovakia, Hungary, Bulgaria, Romania.

• 1989: Collapse of communist regimes across Eastern Europe; Berlin Wall fell in November 1989.

• USSR did not intervene.

Gorbachev Outcome

• Gorbachev’s reforms gave people freedom to demand change.

• His decision not to use force marked a clear departure from past Soviet policy.

• However, long-term economic and social discontent had been building for decades.