By 1945 the wartime alliance between the USA and the USSR was falling apart. President Harry Truman believed communism was expansionist and had to be stopped everywhere it tried to spread.
In 1947 he set out the Truman Doctrine: the USA would give economic and military aid to any country resisting communist takeover. This was the start of a policy called containment.
What containment meant for the Americas: Containment was not just about Europe. Truman's government treated Latin America as part of the same struggle. The US backed anti-communist governments — even harsh, undemocratic ones — as long as they were not communist. Aid, loans and military training were used as tools to keep the region firmly inside the US sphere of influence.
- Truman Doctrine (1947) — promise of US aid to any nation resisting communism, first applied to Greece and Turkey but used as the logic for later action across the Americas
- Marshall Plan (1948) — economic aid to rebuild Western Europe so poverty would not push nations toward communism; a similar logic (aid buys loyalty) later shaped US policy toward Latin America
- Rio Pact (1947) — a mutual-defence treaty binding the USA and Latin American states to treat an attack on one as an attack on all, formalising containment in the Western Hemisphere
- Organization of American States (OAS), 1948 — a US-led regional body used to coordinate anti-communist policy and isolate any government seen as sympathetic to the USSR
At home, fear of communism produced McCarthyism, named after Senator Joseph McCarthy. From 1950 he claimed, without solid proof, that communists had infiltrated the US government, the army and Hollywood. This triggered a wave of accusations, blacklists and congressional hearings (such as the House Un-American Activities Committee, HUAC).
Domestic effects of McCarthyism
- Thousands lost jobs on suspicion alone
- Civil liberties (free speech, due process) were damaged
- A culture of suspicion and conformity spread through schools, unions and the media
Foreign-policy effects of McCarthyism
- Politicians became terrified of looking 'soft on communism'
- This pushed US foreign policy toward more aggressive, uncompromising anti-communist action abroad
- It meant firmer backing for anti-communist regimes in Latin America, since no administration wanted to be blamed for 'losing' a country to communism
McCarthy's influence collapsed in 1954 after televised hearings showed him bullying witnesses without evidence, and the Senate voted to censure him. But the underlying fear he had whipped up — that any softness toward the left was dangerous — outlived him and shaped US policy for decades.
- Social impact — a 'Red Scare' culture of loyalty oaths, censorship and suspicion of intellectuals and immigrants
- Cultural impact — Hollywood blacklists ended careers; films and TV avoided anything that looked sympathetic to the left
- Political impact — both Democrats and Republicans competed to appear toughest on communism, narrowing the range of acceptable foreign policy debate
Free preview
This is the free notes preview
You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:
- FlashcardsLock in vocabulary and key terms with spaced repetition.
- Practice questionsAnswer exam-style questions and get instant AI marking.
- Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
- Personalised study planA daily plan built around your exam date and weak areas.
In June 1950, communist North Korea invaded non-communist South Korea. Truman saw this as a direct test of containment.
Why Truman acted: If the US did nothing, it would look weak everywhere, including in Latin America. The US worried about setting a precedent that communist expansion would go unpunished.
Reasons for US participation
Truman wanted to show containment was a real, active policy, not just words. He acted through the United Nations (the USSR was boycotting the Security Council, so no veto blocked the vote) rather than alone, framing it as collective action against aggression.
Military developments
UN forces (mostly American, commanded by General Douglas MacArthur) pushed North Korean forces back past the original border near the 38th parallel. When MacArthur advanced toward China's border, China entered the war, pushing UN forces back. MacArthur wanted to bomb China and was sacked by Truman for insubordination in 1951 — a clash over how far containment should go.
Diplomatic and political outcomes
The war became a stalemate near the original border. An armistice was signed in July 1953, leaving Korea divided at the 38th parallel, roughly where it started. No formal peace treaty was signed.
Test → Troops → Talks: Korea tested containment, drew in troops, and ended at the table.
Arguments for US involvement
- Fear that inaction would embolden the USSR and China elsewhere, including in Latin America
- Chance to demonstrate resolve through a new international body, the UN
- Domestic political pressure after McCarthyist accusations not to appear weak
Consequences for the region
- Fear that inaction would embolden the USSR and China elsewhere, including in Latin America
- Chance to demonstrate resolve through a new international body, the UN
- Domestic political pressure after McCarthyist accusations not to appear weak
- Latin American troops — Colombia was the only Latin American country to send combat troops to Korea, a gesture that strengthened its ties with Washington
- Rio Pact reinforced — Korea showed Latin American governments the US expected loyalty in the Cold War in exchange for aid and protection
- Military spending — the war pushed US defence budgets up sharply, cementing a permanent Cold War military establishment that would later intervene across the Americas
Link Korea back to the region: Paper 3 questions reward you for explaining why a global event mattered for the Americas, not just narrating it. Always tie Korea back to the theme: it proved containment could mean real wars, it reinforced the OAS/Rio Pact alliance system, and it hardened the domestic political climate (post-McCarthyism) that shaped later US action in Guatemala, Cuba and beyond.
Get feedback like a real examiner
Submit your answers and get instant feedback — what you did well, what's missing, and exactly what to write to score full marks.
Dwight D. Eisenhower became president in 1953, with John Foster Dulles as his Secretary of State. Worried that Korea-style land wars were too costly, they introduced a new strategy known as the New Look.
What was the New Look?: The New Look relied on nuclear weapons and air power ('massive retaliation') instead of large, expensive armies, and on the CIA to fight communism secretly through covert operations — sabotage, propaganda and support for coups — rather than open warfare. The goal was 'more bang for the buck': containment on a smaller budget.
- Massive retaliation — the threat of a huge nuclear response to deter Soviet aggression, cheaper than maintaining large conventional forces
- Covert action — using the CIA to remove governments seen as pro-communist without open US military involvement
- Alliances — building networks of allied and client states (continuing the Rio Pact/OAS approach) so the US did not have to act everywhere alone
The clearest application in the Americas was Guatemala in 1954. President Jacobo Árbenz had introduced land reform that threatened the US-owned United Fruit Company. Eisenhower and Dulles labelled Árbenz's government communist-influenced, and the CIA organised Operation PBSUCCESS, arming and training exiles who overthrew Árbenz in June 1954.
Guatemala 1954 — the New Look in action: No US soldiers invaded. Instead, the CIA funded, trained and supplied a small exile force and ran a psychological-warfare campaign (fake radio broadcasts suggesting a huge invasion was coming). Árbenz resigned rather than risk civil war. It was fast, cheap and deniable — exactly what the New Look promised.
| Feature | Old approach (e.g. Korea) | New Look approach (e.g. Guatemala) |
|---|---|---|
| Main tool | Large conventional army | CIA covert action + nuclear deterrent |
| Cost | Very high (men, money, years) | Low (a few million dollars, months) |
| Visibility | Open, declared war | Secret, deniable |
| Risk | Risk of major war with China/USSR | Risk of long-term instability and resentment |
Short-term success, long-term cost: Short-term: the New Look looked like a cheap, effective way to stop communism without another Korea.
Long-term: removing Árbenz left Guatemala under military rule and helped trigger decades of civil conflict. Covert intervention also fed growing anti-US resentment across Latin America, making the region more suspicious of Washington's motives, not less.
- Reasons for the policy — cheaper than Korea-style wars; fitted a nuclear age; avoided risking US troops directly
- Short-term impact — quick removal of Árbenz; a template for covert action reused in later years
- Long-term impact — instability in Guatemala; growing Latin American distrust of US intentions; a precedent Kennedy would later apply to Cuba