North Invades South: Korean War Begins

Seventy-five thousand North Korean soldiers poured across the 38th parallel before dawn, and the Cold War turned hot for the first time. On June 25, 1950, the Korean People’s Army launched a full-scale invasion of South Korea with Soviet-supplied T-34 tanks, artillery, and aircraft, catching the South Korean military and its American advisors almost completely by surprise. Seoul fell within three days, and the South Korean army was in full retreat toward the southern coast. The invasion was the product of months of planning between North Korean leader Kim Il-sung and Soviet dictator Joseph Stalin. Kim had been pressing Stalin for permission to unify the Korean peninsula by force since 1949, and Stalin finally approved in early 1950 after Mao Zedong’s victory in China and the Soviet Union’s successful nuclear weapons test shifted his calculation of risk. A January 1950 speech by Secretary of State Dean Acheson, which excluded Korea from the American defensive perimeter in Asia, may have reinforced Stalin’s belief that the United States would not intervene. The South Korean military was badly outmatched. The Republic of Korea Army had no tanks, limited artillery, and roughly 98,000 troops, many of them poorly trained conscripts. The North Koreans advanced with 150 T-34 tanks and overwhelming firepower. American occupation forces in Japan, the closest military assets, were understrength and unprepared for combat after years of garrison duty. The invasion triggered an emergency session of the United Nations Security Council, which passed a resolution condemning the attack and calling for member states to assist South Korea. The Soviet Union, which could have vetoed the resolution, was boycotting the Council over the exclusion of Communist China. President Truman committed American air and naval forces on June 27 and ground troops on June 30, beginning a three-year war that would kill more than 2.5 million civilians and leave the Korean peninsula divided to this day.