Each week, The Spokesman-Review examines one question from the Naturalization Test immigrants must pass to become United States citizens.
Today’s question: Why did the U.S. enter the Korean War?
In June 2020, the world observed the 70th anniversary of the Korean War. Korea has become the “forgotten war,” sandwiched between World War II and Vietnam in American history. But it is important to remember, and understand, why the U.S. intervened. Korea represents a key episode in the evolution of the Cold War and foreshadows another fateful conflict.
The origins of the Korean War date to the waning days of World War II. Imperial Japan had occupied the Korean peninsula from 1910 until its surrender in August 1945. The United States was charged with overseeing the Japanese evacuation of Korea, but in liberating Manchuria, the Soviet Union had moved some of its forces into the northern half of the country. U.S. officials proposed a division, at the 38th parallel, with the Soviet Union occupying the north and the U.S., the south. The Soviets agreed.
Meanwhile, the United States found itself in conflict with the Soviet Union over postwar arrangements in Europe. The U.S. and Great Britain had stated their objectives in the Atlantic Charter, and the most important was self-determination for war-ravaged Europeans. Soviet leader Joseph Stalin felt differently. He informed a British envoy in December 1941 that, at a minimum, he wanted control of the territories he had acquired in the Nazi-Soviet pact – the Baltic States, part of Poland and part of modern Moldova.
Stalin also tipped his hand with the observation that each country’s political system would reach as far as its armies did. Stalin’s forces liberated the East European states and half of Germany and Berlin, bringing communist rulers with them. At the 1945 Yalta conference, the U.S. and Great Britain pressed Stalin for self-determination in Soviet-occupied states, but it was clear that Europe would be divided into a communist east and a noncommunist west.
President Harry S. Truman and his advisers understood Eastern Europe would be communist. But they feared that Stalin had designs on the noncommunist world. In response, Truman articulated the Truman, or “containment” doctrine in a 1947 speech before Congress. “I believe,” he stated, “that it must be the policy of the United States to support free peoples who are resisting attempted subjugation by armed minorities or by outside pressures.”
Truman sent economic and military aid to Turkey and Greece, which was fighting a civil war against communist insurgents. He co-authored the Marshall Plan, which aimed to revive western Europe – the U.S.’s biggest trading partner – but also to blunt the appeal of communism among destitute Europeans. In May 1948, Stalin moved to evict the U.S. and its allies from their half of Berlin with a blockade of land routes into the city. As this was an unambiguous attempt to expand communism, Truman answered with an airlift, supplying West Berliners with food and fuel 24/7 for nearly a year, until Stalin relented and lifted the blockade. This policy of “containment” – preventing the expansion of communism beyond its 1945 borders – was to become America’s foreign policy for the duration of the Cold War.
In 1949, communists won a long-running civil war and conquered China. The U.S. had no chance of countering this victory, considering the size of China, and this would have repercussions in Korea.
The 1940s passed relatively quietly on the Korean peninsula. In the south, the U.S. withdrew its occupation troops, opting to provide President Syngman Rhee with economic and military assistance to build a strong Republic of Korea.
The Soviet Union also withdrew its troops and installed a Korean communist, Kim Il Sung, as leader of North Korea, or the Democratic People’s Republic of Korea. As it happened, Kim had lofty ambitions. In early 1949, he lobbied Stalin for an attack on the south that would unify the country under communist rule.
According to Nikita Khrushchev, then in Stalin’s inner circle, Stalin initially feared U.S. intervention but eventually warmed to the idea. The U.S., Khrushchev pointed out, had not contested the communist victory in China. Having withdrawn occupation forces, it could not respond immediately, and North Korean forces might overwhelm the south for a quick victory. Stalin gave Kim the go-ahead and instructed the Soviet military to equip Kim’s army. On June 25, 1950, North Korean troops poured over the 38th parallel and attacked the south.
News of the attack shocked Truman. Years later, he recalled thinking, “If the communists were permitted to force their way into the Republic of Korea without opposition … no small nation would have the courage to resist threats and aggression by stronger communist forces.” He had a ready response in the Truman doctrine. When the United Nations Security Council called for assistance to South Korea, 17 member states, first and foremost the U.S., answered the call. Truman stated initially that the U.S. had no designs on communist territory – he sought a return to the status quo, the division of the country at the 38th parallel.
By early July, U.S. air, naval and ground forces led a multinational coalition of some 700,000 men against North Korea, under the leadership of General Douglas MacArthur. The ensuing conflict saw no quick end. In fact, it escalated perilously when Truman authorized MacArthur to take the fight beyond the 38th parallel, bringing communist China in on the side of North Korea. Ultimately, only the death of Stalin in March 1953 made a negotiated settlement possible. An armistice was signed on July 27, 1953, restoring the 38th parallel as the border between north and south.
The U.S. intervened in Korea because Truman had established that the U.S. would endeavor to contain communism within its 1945 borders. It had helped thwart attempts at communist expansion in Greece and Germany, if not China. The armistice following the Korean War established a demilitarized zone crossing the 38th parallel diagonally that established the border of North Korea and South Korea. The Truman doctrine would also shape the U.S. response to a conflict superficially similar to Korea – Vietnam, in which a communist movement in the north threatened a noncommunist state in the south. “Containment” there would prove disastrously – and fatefully – ineffective.
Brigit Farley is associate professor of history at Washington State University in Pullman. This article is part of a Spokesman Review partnership with the Foley Institute of Public Policy and Public Service at Washington State University.