The Korean War (1950–53), sometimes considered the forgotten war, was the first military confrontation between U.S. and Communist forces in the cold war era. It began on June 25, 1950, when armed forces of the People’s Democratic Republic of Korea (PDRK, or North Korea) attacked across the thirty-eighth parallel, the line that divided Communist North Korea, led by Kim Il Sung, from the non-Communist Republic of Korea (ROK, or South Korea), led by Syngman Rhee.
North Korea’s objective was to unify the two Koreas as a single Communist state. The United States led a military force under the auspices of the United Nations to repel North Korea’s assault on the South. The UN troops successfully cleared North Korean troops from South Korea by October. Thereafter, the Truman administration changed its war aims. The U.S. commander of the UN forces, General Douglas MacArthur, led his army across the thirty-eighth parallel in order to unify Korea under the leadership of the Rhee government. In November the Communist-led People’s Republic of China (PRC) entered the war to counter the advance of UN forces toward the Yalu River, the border between China and North Korea. The war continued for another two-and-a-half years until July 27, 1953, when the United States and the United Nations signed an armistice with China and North Korea.
The Korean peninsula had a long history of invasion and war. Japan occupied Korea from 1910 until its defeat in 1945 in World War II. U.S. forces replaced the Japanese south of the thirty-eighth parallel, and Soviet troops occupied the northern part of the country. These occupations ended in 1947, when the United States and the Soviet Union withdrew their military forces. The United States installed Rhee as president of South Korea, and the Soviets sponsored Kim Il Sung as the leader of North Korea. Both Rhee and Kim declared that there was a single Korean state, of which he was the legitimate leader.
The political climate and geopolitical balance of power in East Asia changed dramatically in 1949, when the Chinese Communist Party, under the leadership of Chairman Mao Zedong, won the Chinese civil war against the Nationalists, led by Jiang Jieshi, and founded the People’s Republic of China. Mao’s victory represented a serious challenge to the U.S. political and military position in East Asia. U.S. policy makers had hoped that Chiang’s Republic of China (ROC) would help the United States impose regional stability. President Harry Truman and Secretary of State Dean Acheson considered Mao a partner of Soviet leader Joseph Stalin, interested in fomenting Communist-inspired revolutions throughout East Asia. Faced with the new reality of the PRC in control of the Chinese mainland and a greatly diminished ROC on the island of Taiwan, Acheson, in January 1950, defined a defense perimeter for the United States in East Asia running through the Philippines, Taiwan, and Japan. South Korea was not included under this shield, because Acheson believed only the three island states he had mentioned were of paramount strategic importance to the United States.
The situation on the Korean peninsula became increasingly tense. After the creation of South Korea and North Korea in 1947, armed forces on each side conducted raids across the thirty-eighth parallel to harass and destabilize the other regime. Early in 1950, Kim asked Mao for support should the North Korean leader decide on a full-scale attack against South Korea. Mao did not explicitly warn Kim against an attack; instead, he offered vague assurances of future support. Mao consulted with Stalin about potential Soviet backing for a North Korean attack on the South Koreans. Stalin urged restraint but promised Mao military support should the United States threaten the PRC.
North Korean forces attacked across the thirty-eighth parallel on June 25. They quickly overcame the poorly armed and outmanned South Korean army and captured Seoul, the capital of South Korea, within days. The Truman administration was shocked by the assault. Truman was already under severe political attack: his critics accused him of having allowed the Communists to win the Chinese civil war. North Korea’s attack appeared to be another sign of Communist power in Asia. The Truman administration had not expected North Korea to move, but when it did, U.S. officials believed Stalin was behind the assault. The president ordered General Douglas MacArthur, the commander of U.S. armed forces stationed in Japan, to send troops to Korea to reinforce the battered South Korean army.
The United States brought the issue of North Korea’s attack before the UN Security Council. Within days, the Security Council labeled North Korea’s actions unacceptable aggression, called on it to withdraw north of the thirty-eighth parallel, and authorized member states to use armed force to help South Korea repel the invasion. The resolution passed without an expected Soviet veto, because the Soviet Union had boycotted the Security Council meetings over the UN refusal to seat the Communist PRC as the official representative of China.
Truman’s firm response to the North Korean attack led to a sharp increase in his public approval, from 36 percent to 46 percent, in early July. Yet the military situation in South Korea was bleak throughout the summer. North Korean forces continued to push South Korean, United States, and allied forces fighting under UN auspices southward until they held only a small semicircle of territory around the southern port of Pusan. Then, on September 15, UN forces under MacArthur landed by sea at Inchon, northwest of Seoul. They surprised and quickly overwhelmed the North Koreans. The UN forces quickly recaptured Seoul, and by early October, they crossed the thirty-eighth parallel and marched into North Korea.
The Truman administration now changed its war aims from repelling aggression from the North to unifying Korea as a non-Communist state. As the UN forces continued their advance into North Korea, Kim became desperate for his future and Mao worried that the United States intended to attack China. The Chinese warned the United States not to approach the Yalu River separating Korea and China, or China would enter the war. MacArthur dismissed these warnings and assured Truman that China would not intervene. The president allowed UN troops to proceed north. As the UN forces approached the Yalu in mid-November, China sent an army of more than 300,000 across the river to attack the approaching troops. The Chinese outnumbered the UN forces and made them retreat south of the thirty-eighth parallel. North Korean troops once more occupied Seoul.
On November 30, Truman stated that the use of atomic weapons in Korea had “always been” under consideration. Such speculation alarmed British leaders whose troops fought alongside the Americans. After Prime Minister Clement Attlee complained, Truman backed away from the threat to use atomic weapons against Chinese or North Korean forces.
In the first three months of 1951, UN forces regrouped, retook Seoul, and advanced to positions near where the war had begun. Truman and his principal foreign policy and military advisors now favored pursuing a limited war in Korea, one that would assure the future of South Korea without sparking a larger conflagration with the Soviet Union.
MacArthur, on the other hand, continued his provocative rhetoric toward North Korea and China. Truman became increasingly angry and frustrated with MacArthur’s belligerent tone. In April MacArthur telegraphed Republican House minority leader Joseph Martin, demanding that Truman “open a second front in Asia” by permitting him to attack China. Truman called this “rank insubordination” the last straw in his tense relationship with the general, and he fired MacArthur. The dismissal ignited a firestorm of public protest against the president, whose approval rating fell to an abysmal 23 percent. MacArthur received a hero’s welcome in Washington and New York when he returned home. Truman’s opponents called for the president’s impeachment, but the political storm subsided. More people came to believe that MacArthur’s incessant demands for victory over North Korea and China might lead to a third world war.
Peace talks between the UN and North Korea began in July 1951, but the war continued unabated. U.S. involvement in a stalemated conflict became increasingly unpopular at home, and Truman announced, in March 1952, that he would not seek reelection. The Korean War became a major issue in the 1952 presidential election campaign. Democratic presidential nominee Adlai Stevenson, the governor of Illinois, supported Truman’s policy of containment and waging limited war in Korea. General Dwight Eisenhower, the Republican nominee, criticized Truman’s handling of a war that had gone on for too long. His campaign adopted a slogan, K1C2 (Korea, Communism, and Corruption), as a way to tap popular discontent with the stalemate in Korea, the fear of communism, and anger at scandals involving administration officials. Eisenhower promised that, if elected, he would go to Korea, survey the state of the war, and recommend ways to end it.
Eisenhower, the popular victorious commander in the European theater during World War II, easily defeated Stevenson. The public was looking for a change of parties after 20 years of Democratic control in the White House and eagerly awaited an end to the Korean War. Eisenhower did go to Korea after the election and returned convinced that the war needed to end quickly. He concluded that both North and South Korea were intransigent in their demands, and that the United States needed to apply pressure on both sides to end the fighting.
After Eisenhower became president, the world political environment changed. Soviet leader Stalin died in March 1953, and his passing offered the promise of reducing cold war tensions. The new U.S. administration threatened both North and South Korea in order to produce movement in the stalled peace negotiations. Washington again hinted that it might use atomic weapons against North Korea, and American officials demanded that South Korea drop its requirement that North Korean prisoners of war held in South Korea be permitted to remain there after the war if they chose. The pace of negotiations quickened.
South Korea released more than 100,000 North Korean POWs rather than forcibly repatriate them. The United States, the United Nations, China, and North Korea signed an armistice on July 27, but South Korea refused to join on the grounds that North Korea had not acknowledged its aggression. The armistice divided North and South Korea by a line between the opposing military forces, roughly along the thirty-eighth parallel. A 10-kilometer-wide demilitarized zone separated the two Koreas. Over the next half-century, this border became the most heavily fortified area in the world. Armed with artillery and tanks, hundreds of thousands of troops from North and South Korea and the United States faced each other. Intermittent negotiations failed to transform the temporary armistice into a full peace agreement.
Cold war tensions between the United States and the PRC remained high during and after the Korean War. The question of “who lost China” became a powerful and divisive issue in American politics. Anti-Communists accused Foreign Service officers, who had reported on the strength of Mao and the Communists and the weakness of Chiang and the Nationalists, of having contributed to the Communists’ victory in the civil war. Between 1951 and 1953, many of these “China Hands” were fired from the State Department.
The Eisenhower administration provided more support for the Nationalist government of Taiwan than Truman had done. Early in the Korean War, the Truman administration had sent the U.S. Navy’s Seventh Fleet into the Strait of Taiwan separating the island from the mainland. The aim was to protect Taiwan from a Communist attack but also to discourage the Nationalists from attacking the mainland. Eisenhower lifted the naval defense of Taiwan in 1953. A year later, Jiang sent 70,000 troops to the islands of Quemoy and Matsu, three miles off the coast of mainland China. In September the Chinese Communists began shelling these islands, and in November Communists planes bombed the Tachen Islands in the Taiwan Strait.
During this first Taiwan Strait Crisis, the Joint Chiefs of Staff recommended using atomic weapons against the mainland, and political pressure mounted on Eisenhower to send U.S. troops to protect the offshore islands. In the fall of 1954, the president decided against direct U.S. military involvement in the crisis. Instead, the United States signed a defense treaty with the Republic of China. Under this agreement, the United States promised to protect the island of Taiwan but was silent about the offshore islands. The first Taiwan Strait Crisis intensified in April 1955 when the president said that “A-bombs might be used . . . as you would use a bullet.” China said it was willing to negotiate with the United States over the islands and the future of Taiwan. On May 1 China stopped shelling the islands.
Ambassadorial talks between the United States and Communist China began in the summer of 1955 and continued, off and on, mostly in Warsaw, for the next 16 years, until President Richard Nixon announced that he would visit Beijing. These conversations made no progress on the future of the Republic of China in Taiwan, but they did lead to the repatriation of U.S. and Chinese citizens who had been stranded in China or the United States, respectively, during the Chinese civil war and the Korean War. A second Taiwan Strait Crisis began in August 1958, when the Communists resumed shelling Quemoy and Matsu. Eisenhower asserted that the shelling was part of a plan “to liquidate all of the free world positions in the Western Pacific.” China stopped shelling the offshore islands on January 1, 1959.
Tensions persisted, and the United States continued to see Communist China as a major threat. During the 1960 presidential campaign, Democratic candidate John F. Kennedy accused the Eisenhower administration of sending mixed signals to China, which had encouraged its aggressive moves in the Taiwan Strait. The growing split between Mao and the Soviet Union, under the leadership of Nikita Khrushchev, ratcheted up the cold war competition. In January 1961, Khrushchev, responding to Mao’s accusation that the Soviet Union had retreated from its earlier revolutionary fervor, pledged his country’s support for “wars of national liberation” around the world. The new Kennedy administration considered Khrushchev’s promise a direct challenge to the United States and its support of pro-western governments. Kennedy increased U.S. support to the government of the Republic of Vietnam, or South Vietnam, as a way to counter Soviet and Communist Chinese influence in Southeast Asia.
The memory of the Korean War and Chinese intervention in it was ever present as the United States deepened its involvement in the Vietnam War during Kennedy’s administration and the first 18 months of Lyndon Johnson’s presidency. Democratic presidents were haunted by fear that their opponents would resurrect the cry “who lost China?” and charge them with “losing” Vietnam to the Communists. U.S. policy makers believed that the preservation of South Vietnam as an anti-Communist bulwark against what they considered to be a newly aggressive Communist North Vietnam was essential. Kennedy and Johnson administration officials both drew analogies between South Vietnam and South Korea and between North Vietnam and North Korea. They also drew sobering lessons from the Korean War and wished, at all costs, to avoid Chinese intervention in Vietnam.
See also era of consensus, 1952–64; Vietnam and Indochina wars.
FURTHER READING. Jian Chen, China’s Road to the Korean War: The Making of Sino-American Confrontation, 1994; Rosemary Foot, The Wrong War: American Policy and the Dimensions of the Korean Conflict, 1985; John Lewis Gaddis, The Cold War: A New History, 2006; David Halberstam, The Coldest Winter: America and the Korean War, 2007; Yuen Foong Khong, Analogies at War: Korea, Munich, Dien Bien Phu, and the Vietnam Decision of 1965, 1992; Michael Schaller, Douglas MacArthur: The Far Eastern General, 1989; William Stueck, The Korean War: An International History, 1995; Idem, Rethinking the Korean War: A New Diplomatic and Strategic History, 2002; Nancy Bernkopf Tucker, Taiwan, Hong Kong, and the United States, 1945–1992: Uncertain Friendships, 1994; Odd Arne Westad, The Global Cold War: Third World Interventions and the Making of Our Times, 2005.
ROBERT SCHULZINGER