IB History Invasion of South Korea and UN Response Notes

Invasion and UN Response: From 25 June 1950 to the Armistice

1. At 4:00 a.m. on 25 June 1950, the Korean People's Army crossed the 38th parallel with 135,000 troops, Soviet T-34 tanks, and air support. Within three days, Seoul had fallen.
2. South Korean forces collapsed rapidly, retreating southward. The United States responded immediately.
3. President Truman committed air and sea forces on 25 June, and ground troops on 27 June. The UN Security Council passed Resolution 83 recommending member states assist South Korea.
4. Fifteen other nations eventually contributed troops under US General Douglas MacArthur's overall command, though US forces made up the vast majority. By September 1950, UN and South Korean forces had been pushed back to the Pusan Perimeter in the far southeast of the peninsula.
5. MacArthur's amphibious landing at Inchon on 15 September 1950 turned the tide dramatically. UN forces swept northward, recaptured Seoul, and crossed the 38th parallel into North Korea.
6. The decision to cross the 38th parallel was controversial. Truman and his advisors judged that rolling back communism, not just containing it, was achievable in Korea.
7. But as UN forces approached the Yalu River, China warned it would intervene. MacArthur dismissed the warnings.
8. In October 1950, 300,000 Chinese troops crossed the Yalu and drove UN forces back south.

1. Truce talks began at Kaesong in July 1951 but stalled repeatedly over the question of prisoner repatriation. The armistice was signed on 27 July 1953 at Panmunjom, ending active fighting.
2. The war killed approximately 36,000 Americans, 400,000 South Korean soldiers, and perhaps 3 million Korean civilians and military combined.

Invasion of South Korea and UN response: Evidence, Outcomes, and Limits

1. North Korean forces crossed the 38th parallel on 25 June 1950. The attack used tanks, artillery, and coordinated infantry against a less heavily armed South Korean army.
2. Seoul fell within days. South Korean units retreated while civilians fled south through disrupted roads and bridges.
3. The UN Security Council condemned the invasion. Resolution 82 demanded withdrawal of North Korean forces.
4. The Soviet delegate was boycotting the Council. Moscow protested the continued Chinese seat held by the Nationalist government on Taiwan and could not veto action.
5. Resolution 83 recommended military assistance. The United States organised the main combat response under UN authority.
6. General Douglas MacArthur commanded the UN force. American troops formed the majority, while South Korea and other member states contributed forces.
7. Early US units were poorly prepared. Task Force Smith and other formations failed to stop the North Korean advance.
8. The defenders held the Pusan Perimeter. Supply through the port of Busan and concentrated firepower prevented total defeat.
9. The Inchon landing began on 15 September 1950. The amphibious operation cut North Korean supply lines and helped retake Seoul.
10. UN forces crossed the 38th parallel. The mission shifted from restoring South Korea to attempting reunification under the Seoul government.
11. The General Assembly supported wider action. The Soviet return to the Security Council made further Council authorisation difficult.
12. Chinese leaders warned against advance toward the Yalu. The warnings were discounted or interpreted as bluff.
13. UN forces moved rapidly into North Korea. Extended supply lines and dispersed units increased vulnerability.
14. The response saved the Republic of Korea. It also transformed a defensive intervention into a wider war involving China.
15. UN authority depended heavily on American power. The coalition gave international legitimacy, but US strategy and command decisions shaped operations.