Overview
The Korean War began when North Korea invaded South Korea in 1950. The United Nations, with the United States as the principal force, came to the aid of South Korea. China, with assistance from the Soviet Union, came to the aid of North Korea. The war arose from the division of Korea at the end of World War II and from the global tensions of the Cold War that developed immediately afterwards.
Korea was ruled by Japan from 1910 until the closing days of World War II. In August 1945, the Soviet Union declared war on Japan, as a result of an agreement with the United States, and liberated Korea north of the 38th parallel. U.S. forces subsequently moved into the south. By 1948, as a product of the Cold War between the Soviet Union and the United States, Korea was split in to two separate governments. Both governments claimed to be the legitimate government of Korea, and neither side accepted the border as permanent. The civil war escalated into open warfare when North Korean forces—supported by the Soviet Union and China—moved to the south to unite the country on 25 June 1950. On that day, the United Nations Security Council recognized this North Korean act as invasion and called for an immediate ceasefire. Twenty-one countries of the United Nations eventually contributed to the defense of South Korea, with the United States providing 88% of the UN's military personnel. On the North Korean side, Joseph Stalin "planned, prepared, and initiated" the invasion, creating "detailed [war] plans" that were communicated to the North Koreans.
After the first two months of the conflict, South Korean forces were on the point of defeat, forced back to the Pusan Perimeter. In September 1950, an amphibious UN counter-offensive was launched at Inchon, and cut off many of the North Korean attackers. Those that escaped envelopment and capture were rapidly forced back north all the way to the border with China at the Yalu River, or into the mountainous interior. At this point, in October 1950, Chinese forces crossed the Yalu and entered the war. Chinese intervention triggered a retreat of UN forces which continued until mid-1951. After these dramatic reversals of fortune, which saw Seoul change hands four times, the last two years of conflict became a war of attrition, with the front line close to the 38th parallel. The war in the air, however, was never a stalemate. North Korea was subject to a massive bombing campaign. Jet fighters confronted each other in air-to-air combat for the first time in history, and Soviet pilots covertly flew in defense of their Communist allies.
Inchon Landing
General Douglas MacArthur, UN Command (seated), observes the naval shelling of Incheon from USS Mount McKinley, 15 September 1950
As a result of early Chinese tactical successes, General Douglas MacArthur, who had been in command of U.N. forces in Korea, argued in favor of using nuclear weapons against China and/or the North Korean interior in order to disrupt Chinese supply lines and force negotiations. MacArthur attempted to orchestrate public support for bombing China, as well as for assisting an invasion of the mainland by KMT forces, led by Chiang Kai-shek. MacArthur's stance in this regard contributed to his controversial dismissal by President Truman. In April 1951, Truman relieved MacArthur of his duties and replaced him with Ridgway.
The fighting ended on 27 July 1953, when an armistice was signed. The agreement created the Korean Demilitarized Zone to separate North and South Korea, and allowed the return of prisoners. However, no peace treaty has been signed, and the two Koreas are technically still at war. Periodic clashes, many of which were deadly, have continued to the present.
U.S. Intervention
The Truman administration was unprepared for the invasion. Korea was not included in the strategic Asian Defense Perimeter outlined by Secretary of State Dean Acheson. Military strategists were more concerned with the security of Europe against the Soviet Union than East Asia. At the same time, the Administration was worried that a war in Korea could quickly widen into another world war should the Chinese or Soviets decide to get involved as well.
A major consideration was the possible Soviet reaction in the event that the US intervened. The Truman administration was fretful that a war in Korea was a diversionary assault that would escalate to a general war in Europe once the United States committed in Korea. At the same time, "[t]here was no suggestion from anyone that the United Nations or the United States could back away from [the conflict]." Truman believed if aggression went unchecked a chain reaction would be initiated that would marginalize the United Nations and encourage Communist aggression elsewhere. The Truman administration was still uncertain if the attack was a ploy by the Soviet Union or just a test of U.S. resolve. The decision to commit ground troops became viable when a communiqué was received on 27 June indicating the Soviet Union would not move against U.S. forces in Korea. The Truman administration now believed it could intervene in Korea without undermining its commitments elsewhere.
Casualties
According to the data from the U.S. Department of Defense, the United States suffered 33,686 battle deaths, along with 2,830 non-battle deaths, during the Korean War. U.S. battle deaths were 8,516 up to their first engagement with the Chinese on 1 November 1950. South Korea reported some 373,599 civilian and 137,899 military deaths. Western sources estimate the PVA suffered about 400,000 killed and 486,000 wounded, while the KPA suffered 215,000 killed and 303,000 wounded.
Data from official Chinese sources, on the other hand, reported that the PVA had suffered 114,000 battle deaths, 34,000 non-battle deaths, 340,000 wounded, 7,600 missing and 21,400 captured during the war. Among those captured, about 14,000 defected to Taiwan, while the other 7,110 were repatriated to China. Chinese sources also reported that North Korea had suffered 290,000 casualties, 90,000 captured and a "large" number of civilian deaths.
Recent scholarship has put the full battle death toll on all sides at just over 1.2 million.
Aftermath
Postwar recovery was different in the two Koreas. South Korea stagnated in the first postwar decade. In 1953, South Korea and the United States concluded a Mutual Defense Treaty. In 1960, the April Revolution occurred and students joined an anti-Syngman Rhee demonstration; 142 were killed by police; in consequence Syngman Rhee resigned and left for exile in the United States.
From 1965 to 1973, South Korea dispatched troops to Vietnam and received $235,560,000 allowance and military procurement from the United States. GNP increased fivefold during the Vietnam War. South Korea industrialized and modernized. Contemporary North Korea remains underdeveloped. South Korea had one of the world's fastest-growing economies from the early 1960s to the late 1990s.
Following extensive USAF bombing, North Korea "had been virtually destroyed as an industrial society." After the armistice, Kim Il-Sung requested Soviet economic and industrial assistance. In September 1953, the Soviet government agreed to "cancel or postpone repayment for all ... outstanding debts", and promised to grant North Korea one billion rubles in monetary aid, industrial equipment and consumer goods. Eastern European members of the Soviet Bloc also contributed with "logistical support, technical aid, [and] medical supplies." China cancelled North Korea's war debts, provided 800 million yuan, promised trade cooperation, and sent in thousands of troops to rebuild damaged infrastructure.
Postwar, about 100,000 North Koreans were executed in purges. According to Rummel, forced labor and concentration camps were responsible for over one million deaths in North Korea from 1945 to 1987; others have estimated 400,000 deaths in concentration camps alone. Estimates based on the most recent North Korean census suggest that 240,000 to 420,000 people died as a result of the 1990s North Korean famine and that there were 600,000 to 850,000 unnatural deaths in North Korea from 1993 to 2008. The North Korean government has been accused of "crimes against humanity" for its alleged culpability in creating and prolonging the 1990s famine.
South Korean anti-Americanism after the war was fueled by the presence and behavior of American military personnel (USFK) and U.S. support for the authoritarian regime, a fact still evident during the country's democratic transition in the 1980s. However, anti-Americanism has declined significantly in South Korea in recent years, from 46% favorable in 2003 to 74% favorable in 2011, making South Korea one of the most pro-American countries in the world.
Korean War Montage
Clockwise from top: A column of the U.S. 1st Marine Division's infantry and armor moves through Chinese lines during their breakout from the Chosin Reservoir; UN landing at Incheon harbor, starting point of the Battle of Incheon; Korean refugees in front of an American M26 Pershing tank; U.S. Marines, led by First Lieutenant Baldomero Lopez, landing at Incheon; F-86 Sabre fighter aircraft