During the Korean War, U.S. Marines land at Inchon on the west coast of Korea, 100 miles south of the 38th parallel and just 25 miles from Seoul. The location had been criticized as too risky, but U.N. Supreme Commander Douglas MacArthur insisted on carrying out the landing. By the early evening, the Marines had overcome moderate resistance and secured Inchon. The brilliant landing cut the North Korean forces in two, and the U.S.-led U.N. force pushed inland to recapture Seoul, the South Korean capital that had fallen to the communists in June. Allied forces then converged from the north and the south, devastating the North Korean army and taking 125,000 enemy troops prisoner.
The Korean War began on June 25, 1950, when 90,000 North Korean troops stormed across the 38th parallel, catching the Republic of Korea's forces completely off guard and throwing them into a hasty southern retreat. Two days later, U.S. President Harry Truman announced that the United States would intervene in the conflict, and on June 28 the United Nations approved the use of force against communist North Korea. On June 30, Truman agreed to send U.S. ground forces to Korea, and on July 7 the Security Council recommended that all U.N. forces sent to Korea be put under U.S. command. The next day, General Douglas MacArthur was named commander of all U.N. forces in Korea.
In the opening months of the war, the U.S.-led U.N. forces rapidly advanced against the North Koreans, but Chinese communist troops entered the fray in October, throwing the Allies into a hasty retreat. In April 1951, Truman relieved MacArthur of his command after he publicly threatened to bomb China in defiance of Truman's stated war policy. Truman feared that an escalation of fighting with China would draw the Soviet Union into the Korean War.
By May 1951, the communists were pushed back to the 38th parallel, and the battle line remained in that vicinity for the remainder of the war. On July 27, 1953, after two years of negotiation, an armistice was signed, ending the war and reestablishing the 1945 division of Korea that still exists today. Approximately 150,000 troops from South Korea, the United States, and participating U.N. nations were killed in the Korean War, and as many as one million South Korean civilians perished. An estimated 800,000 communist soldiers were killed, and more than 200,000 North Korean civilians died.