Korean War

War from 1950 to 1953 between North Korea (supported by China) and South Korea, aided by the United Nations (the troops were mainly US). North Korean forces invaded South Korea on 25 June 1950, and the Security Council of the United Nations, owing to a walk‐out by the USSR, voted to oppose them. The North Koreans held most of the South when US reinforcements arrived in September 1950 and forced their way through to the North Korean border with China. The Chinese retaliated, pushing them back to the original boundary by October 1950; truce negotiations began in 1951, although the war did not end until 1953. The Korean War established that the USA was prepared to intervene militarily to stop the spread of communism. After 1953 the Korean peninsula remained a Cold War battleground.

By September 1950, the North Koreans had overrun most of the South, with the United Nations (UN) forces holding a small area, the Pusan perimeter, in the southeast. The course of the war changed after the surprise landing of US troops later the same month at Inchon on South Korea's northwest coast. The troops, led by General Douglas MacArthur, fought their way through North Korea to the Chinese border in little over a month. On 25 October 1950, Chinese troops attacked across the Yalu River, driving the UN forces below the 38th parallel.

Truce talks began in July 1951, and the war ended two years later, with the restoration of the original boundary on the 38th parallel. The armistice was signed 27 July 1953 with North Korea, but South Korea did not participate, and a peace treaty did not follow.

At the end of the Korean War, it was estimated that the countries involved in the three‐year conflict had suffered a total of over 4 million casualties, of which 2 million were civilians. A total of 36,940 Americans lost their lives in the Korean theatre; of these 33,665 were killed in action, while 3,275 died there of non‐hostile causes. There were 92,134 Americans wounded in action and, almost 50 years later, there were still 8,176 reported as missing. A total of 1,789,000 Americans served in the Korean theatre between 25 June 1950 and 26 July 1953. South Korea sustained 1,312,836 casualties, including 415,004 dead. Casualties among other UN allies totalled 16,532, including 3,094 dead. Estimated North Korean casualties numbered 2 million, including about 1 million civilians and about 520,000 soldiers. An estimated 900,000 Chinese soldiers lost their lives in combat. The economic and social devastation experienced by the Korean nation was inestimable.

The Korean War was the first incidence of the two Cold War superpowers, the USA and the USSR, fighting for control over other countries. Although the USSR was not directly involved in the Korean War, it supplied arms to the communist Chinese government in order to support communism in North Korea. For both sides, the Korean War demonstrated their determination to protect countries that they saw as friendly and of similar ideological intent.

By saving South Korea from destruction by communist North Korea, the USA demonstrated its willingness to intervene in any part of the world. Asia was seen as a key battleground in the struggle between capitalism and democracy on the one hand, and communism on the other. The two Koreas had minimal contact until the late 1990s, and their border remained the most heavily militarized in the world.