Korean War (1950-1953)

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Editor: Spencer C. Tucker
Date: 2008
Cold War: A Student Encyclopedia
Publisher: ABC-Clio
Document Type: Event overview
Pages: 10
Content Level: (Level 5)

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Korean War (1950-1953)

The Korean War was a watershed conflict within the Cold War. The first shooting war of the Cold War, it was also the first limited war of the nuclear age. Korea was long the scene of confrontation among China, Japan, and Russia. Controlled by either China or Japan for most of its modern history, Korea was divided in half after World War II. Wartime agreements called for the United States to temporarily occupy southern Korea up to the 38th Parallel, while the Soviet Union did the same north of that line. The Cold War brought the permanent division of Korea into two states.

Efforts to establish a unified Korea failed, and in September 1947 the United States referred the issue to the United Nations (UN), which called for a unified Korean government and the withdrawal of occupation forces. In January 1948 Soviet authorities refused to permit a UN commission to oversee elections in northern Korea, but elections for an assembly proceeded in southern Korea that spring. By August 1948 the Republic of Korea (ROK, South Korea) had officially formed with its capital at Seoul and was headed by seventy-year-old Syngman Rhee, a staunch conservative. Washington then terminated its military government and agreed to train South Korea's armed forces.

In September 1948 the communists formed the Democratic People's Republic of Korea (DPRK, North Korea) with its capital at Pyongyang and led by veteran communist Kim Il Sung. Kim had fought the Japanese occupation and ended World War II as a major in the Soviet Army.

Both Korean governments claimed authority over the entire peninsula, but in December 1948 the UN General Assembly endorsed the ROK as the Page 1152  |  Top of Articleonly lawfully elected government. That same month the USSR announced that it had withdrawn its forces from North Korea. The United States withdrew all its troops from South Korea by June 1949.

KOREAN WAR, 19501953

KOREAN WAR, 1950–1953

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Beginning in May 1948, sporadic fighting began along the 38th Parallel. Washington, fearful that the United States might be drawn into a civil war, purposely distanced itself from these clashes. President Harry S. Truman announced that fighting in Korea would not automatically lead to U.S. military intervention. In January 1950 Secretary of State Dean Acheson excluded Korea from the U.S. strategic Asian defensive perimeter. The Joint Chiefs of Staff (JCS) agreed with this, as did U.S. Far Eastern commander General of the Army Douglas MacArthur. Such pronouncements undoubtedly encouraged Kim to believe that the United States would not fight for Korea.

For many years North Korea, the USSR, and the People's Republic of China (PRC) maintained that the Korean War began with a South Korean attack on North Korea. This was propaganda. Beginning in late 1949 North Korea prepared for full-scale war. Its Korean Peoples Army (KPA) was well armed with Soviet weapons, including such modern offensive arms as heavy artillery, T-34 tanks, trucks, automatic weapons, and about 180 new aircraft. The KPA numbered about 135,000 men in ten divisions.

South Korea's military situation was far different. The Republic of Korea Army (ROKA) lacked equipment and trained leaders because of Washington's unwillingness to fight in Korea and because the meager U.S. defense budget would not allow it. ROKA training was incomplete and lacked heavy artillery, tanks, and antitank weapons. South Korea had no air force apart from trainers and liaison aircraft. The South Korean military numbered 95,000 men in eight divisions, only four of which were at full strength.

Washington was aware of the North Korean military buildup but believed that the communist powers would not risk war. Limited war was still a foreign concept to U.S. planners. The U.S. military was also woefully unprepared and ill-equipped. The army numbered only nine divisions and 630,000 men.

Kim planned to use his military superiority to invade and quickly conquer South Korea. Twice he consulted Soviet leader Josef Stalin, promising him victory in a manner of weeks, assuring him that there would be a communist revolution in South Korea, and insisting that Washington would not intervene. Moscow and Beijing were actively preparing for the invasion as early as the spring of 1949, and Russian military advisors assisted in its planning. Stalin concluded that even if the United States decided to intervene, it would come too late.

Stalin pledged military assistance but not direct Soviet military involvement. He also insisted that Kim meet with PRC leader Mao Zedong and secure his assent to the plans. In late 1949, Mao released the People's Liberation Army (PLA) 164th and 166th Divisions of Korean volunteers who had fought against the Japanese and in the Chinese Civil War, providing North Korea with 30,000–40,000 seasoned troops.

On 25 June 1950, KPA forces invaded South Korea. The UN Security Council called for an immediate cease-fire and the withdrawal of North Page 1154  |  Top of ArticleKorean forces, a resolution that went unchallenged because of a Soviet UN boycott. On 27 June the Security Council asked UN member states to furnish assistance to the South Korea. President Harry S. Truman also extended U.S. air and naval operations to include North Korea and authorized U.S. Army troops to protect the port of Pusan. Upon General MacArthur's recommendation, President Truman committed U.S. Far Eastern ground forces to Korea on 30 June.

Korean War (1950-1953)

The invasion caught both MacArthur and Washington by surprise. Yet U.S. intervention was almost certain, given the Truman Doctrine, domestic political fallout from the communist victory in China in 1949, and the belief that success in Korea would embolden the communists elsewhere. During the three-year conflict, no war was ever formally declared; Truman labeled it a “police action.”

At the time of the invasion the United States had four poorly trained and equipped divisions in Japan. By cannibalizing his 7th Infantry Division, MacArthur was able to dispatch the 24th and 25th Infantry Divisions and the 1st Cavalry Division to Korea within two weeks. Meanwhile, Seoul fell on 28 June. Most of South Korea's equipment was lost when the bridges spanning the Han River were prematurely blown.

On 5 July the first American units battled the KPA at Osan, 50 miles south of Seoul. Expected to stop a KPA division, Task Force Smith consisted of only 540 men in two rifle companies and an artillery battery. The KPA, spearheaded by T-34 tanks, easily swept it aside.

At the request of the UN Security Council, the UN set up a military command in Korea. Washington insisted on a U.S. commander, and on 10 July Truman appointed MacArthur to head the UN Command (UNC). Seventeen nations contributed military assistance, and at peak strength UNC forces numbered about 400,000 South Korean troops, 250,000 U.S. troops, and 35,000 troops from other nations. Tw o British and Canadians units formed the 1st Commonwealth Division. Turkey provided a brigade, and there were troops from Australia, Thailand, the Philippines, Colombia, Ethiopia, France, Page 1155  |  Top of ArticleGreece, Belgium, Luxembourg, the Netherlands, and New Zealand. Other nations provided medical units.

U.S. forces were unprepared for the fighting. Difficult terrain, primitive logistics, poor communication, and refugees did as much to delay the North Korean offensive as did the defenders. In the chaotic atmosphere of the UNC retreat, both sides committed atrocities. The South Koreans executed some 2,000 political prisoners. U.S. and UNC troops shot a number of innocent civilians as the KPA infiltrated throngs of refugees and used them as human shields. North Korea committed far greater atrocities during its occupation of South Korea, however, slaying an estimated 26,000 political opponents. The KPA also executed American prisoners of war (POWs) in the fall of 1950.

By mid-July UNC troops had been pushed back into the so-called Pusan Perimeter, an area of 30–50 miles around the vital port of Pusan on the southeastern coast of Korea. Here U.S. and ROK forces bought valuable time and ultimately held. This success was attributable to UNC artillery, control of the skies, and Eighth Army (EUSAK, Eighth U.S. Army in Korea) commander Lieutenant General Walton Walker's brilliant mobile defense. The KPA also failed to employ its early manpower advantage to mount simultaneous attacks along the entire perimeter.

Even as the battle for the Pusan Perimeter raged, MacArthur was planning an amphibious assault behind enemy lines. Confident that he could hold Pusan, MacArthur deliberately weakened EUSAK to build up an invasion force. He selected Inchon as the invasion site. As Korea's second largest port and being only 15 miles from Seoul, Inchon was close to the KPA's main supply line south. Seizing it would cut off KPA troops to the south. Mac-Arthur also knew that he could deal North Korea a major political blow if Seoul were promptly recaptured.

The Inchon landing was a risky venture, and few besides MacArthur favored it. Inchon posed the daunting problems of a thirty-two-foot tidal range that allowed only six hours in twenty-four for sea resupply, a narrow winding channel, and high seawalls. On 15 September, Major General Edward Almond's X Corps of the 1st Marine Division and the 7th Infantry Division commenced the invasion. Supported by naval gunfire and air attacks, the Marines secured Inchon with relatively few casualties. UNC forces reentered Seoul on 24 September.

At the same time, EUSAK broke out of the Pusan Perimeter and drove north, linking up with X Corps on 26 September. Only one-quarter to one-third of the KPA escaped north of the 38th Parallel. Pyongyang ignored MacArthur's call for surrender, and on 1 October South Korean troops crossed into North Korea. On 7 October the UN General Assembly passed a resolution calling for a unified, independent, and democratic Korea, and two days later MacArthur ordered U.S. forces across the 38th Parallel. Pyongyang fell on 19 October as stunned KPA forces fled north.

MacArthur then divided his forces for the drive to the Yalu River. He ordered X Corps transported by sea around the Korean Peninsula to the east coast port of Wonsan. Almond would then clear northeastern Korea. EUSAK Page 1156  |  Top of Articlewould remain on the west coast and drive into northwest Korea. The two commands would be separated by a gap of between 20 and 50 miles. Mac-Arthur believed, falsely as it turned out, that the north-south Taebaek Mountain range would obviate large-scale communist operations there. The Eighth Army crossed the Chongchon River at Sinanju, and by 1 November elements of the 24th Division were only 18 miles from the Yalu. Several days earlier a South Korean unit reached the Yalu, the only UNC unit to get there.

China now entered the war—unofficially. Alarmed over possible U.S. bases adjacent to Manchuria, Mao had issued warnings about potential Chinese military intervention. He believed that the United States would be unable to counter the Chinese numerical advantage and viewed American troops as soft and unused to night fighting. On 2 October Mao informed Stalin that China would enter the war.

U.S. Air Force North American F-86 Sabre jet fighters at a South Korean air base in the Republic of Korea (ROK, South Korea) June 1951. (National Archives and Records Administration)

U.S. Air Force North American F-86 Sabre jet fighters at a South Korean air base in the Republic of Korea (ROK, South Korea) June 1951. (National Archives and Records Administration)

Stalin agreed to move Soviet MiG-15 fighters already in China to the Korean border. In this position they could cover the Chinese military buildup and prevent U.S. air attacks on Manchuria. Soviet pilots began flying missions against UNC forces on 1 November and bore the brunt of the communists’ air war. Stalin also ordered other Soviet air units to deploy to China, train Chinese pilots, and then turn over aircraft to them.

Although Russian and Chinese sources disagree on what the Soviet leader promised Mao, Stalin clearly had no intention of using his air units for anything other than defensive purposes. China later claimed that Stalin had promised complete air support for their ground forces, but this never materialized.

On 25 October Chinese troops entered the fighting in northwestern Korea, and Walker wisely brought the bulk of EUSAK back behind the Chongchon River. Positions then stabilized, and the Chinese offensive slackened. The Chinese also attacked in northeastern Korea before halting operations and breaking contact. On 8 November the first jet battle in history occurred when an American F-80 shot down a MiG-15 over Sinanju.

The initial Chinese incursion ended on 7 November. In a meeting with President Truman at Wake Island on 15 October, General MacArthur had assured the president that the war was all but won but that if the Chinese were to intervene, their forces would be slaughtered. UNC air-power, he believed, would nullify any Chinese threat. Yet from 1 November 1950 to October 1951, MiGs so dominated the Yalu River area that U.S. B-29 bombers had to cease daylight operations.

The initial Chinese intervention had consisted of eighteen volunteer divisions. In early November they moved an additional twelve divisions into Korea, totaling some 300,000 men. MacArthur responded by ordering the air force to destroy the bridges over the Yalu. Washington revoked the order, but MacArthur complained that this Page 1157  |  Top of Articlethreatened his command. Washington gave in. On 8 November, 79 B-29s and 300 fighter-bombers struck bridges and towns on either side of the Yalu. The bombing had little effect. At the time most of the Chinese were in North Korea, and the Yalu was soon frozen.

Meanwhile, Washington debated how to proceed. The political leadership and the JCS under the chairmanship of General Omar Bradley believed that Europe was the top priority. Washington decided that while Manchuria would remain off-limits, MacArthur could take other military steps that he deemed advisable, including resumption of the offensive. The Democrats were reluctant to show weakness in Korea, and the Republicans had gained seats in the November 1950 congressional elections.

While much was being made in the United States about the prohibitions of strikes on Manchuria, the communist side also exercised restraint. With the exception of a few ancient biplanes that sometimes bombed UNC positions at night, communist airpower was restricted to north of Pyongyang. No effort was made to strike Pusan, and UNC convoys traveled without fear of air attack. Nor did communist forces attempt to disrupt Allied sea communications.

MacArthur had made X Corps dependent logistically on EUSAK instead of Japan, and Walker insisted on delaying resumption of the offensive until he could build up supplies. Weather also played a factor, with temperatures already below zero. Finally, Walker agreed to resume the offensive on 24 November. To the east, X Corps was widely dispersed.

MacArthur seemed oblivious to any problems, seeing the advance as an occupation rather than an offensive. It went well on the first day, but on the night of 25–26 November the Chinese attacked the Eighth Army in force. The Americans held, but on 26 December the South Korean II Corps disintegrated, exposing EUSAK's right flank. The Chinese poured eighteen divisions into the gap, endangering the whole Eighth Army. In a brilliant delaying action at Kunu-ri, the U.S. 2nd Division bought time for the other EUSAK divisions to recross the Chongchon. MacArthur now ordered a retirement just below the 38th Parallel to protect Seoul.

Washington directed MacArthur to pull X Corps out of northeastern Korea to prevent it from being flanked. Under heavy Chinese attack, X Corps withdrew to the east coast for seaborne evacuation along with the South Korean I Corps. The retreat of the 1st Marine Division and some army elements from the Chanjin Reservoir to the coast was one of the most masterly withdrawals in military history. X Corps was redeployed to Pusan by sea. On 10 December, Wonsan was evacuated. At Hungnam through 24 December, 105,000 officers and men were taken off along with about 91,000 Korean refugees who did not want to remain in North Korea.

The Korean War had entered a new phase: in effect, the UNC was now fighting China. MacArthur refused to accept a limited war and publicized his views to his supporters in the United States, making reference to “inhibitions” placed on his conduct of the war. UNC morale plummeted, especially with General Walker's death in a jeep accident on 22 December. Not until Lieutenant General Matthew Ridgway arrived to replace Walker did the situation improve. In the United States, Truman found himself under heavy Page 1158  |  Top of Articlepressure from Republicans to pursue the war vigorously. But the administration reduced its goal in Korea to restoring the status quo ante bellum.

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In August armistice talks broke down, and later that month the Battle of Bloody Ridge began, developing into the Battle of Heartbreak Ridge that lasted until mid-October.

UNC forces again had to retreat when the Chinese launched a New Year's offensive, retaking Seoul on 4 January. But the Chinese outran their supply lines, and Ridgway took the offensive. His methodical, limited advance was designed to inflict maximum punishment rather than to secure territory. Nonetheless, by the end of March UNC forces recaptured Seoul, and by the end of April they were again north of the 38th Parallel.

On 11 April 1951 President Truman relieved MacArthur of command, appointing Ridgway in his stead. Lieutenant General James Van Fleet took over EUSAK. Although widely unpopular at the time, MacArthur's removal was fully supported by the JCS, as MacArthur had publicly expressed his disdain of limited war. He returned home to a hero's welcome, but much to his dismay, political support for him promptly faded.

On 22 April the Chinese counterattacked in Korea. Rather than expend his troops in a defensive stand, Van Fleet ordered a methodical withdrawal with maximum artillery and air strikes against communist forces. The Chinese pushed the UNC south of the 38th Parallel, but the offensive was halted by 19 May.

UNC forces then counterpunched, and by the end of May the front stabilized just above the 38th Parallel. The JCS generally limited EUSAK to that line, allowing only small local advances to gain more favorable terrain.

The war was now stalemated, and a diplomatic settlement seemed expedient. On 23 June 1951 Soviet UN representative Jacob Malik proposed a cease-fire. With the Chinese expressing interest, Truman authorized Ridgway to negotiate. Meetings began on 10 July at Kaesong, although hostilities would continue until an armistice was signed.

UNC operations from this point were essentially designed to minimize friendly casualties. Each side had built deep defensive lines that would be costly to break through. In August armistice talks broke down, and later that month the Battle of Bloody Ridge began, developing into the Battle of Heartbreak Ridge that lasted until mid-October. In late October negotiations resumed, this time at Panmunjom, although the fighting continued. Half of the war's casualties occurred during the period of armistice negotiations.

On 12 November 1951 Ridgway ordered Van Fleet to cease offensive operations. Fighting now devolved into raids, local attacks, patrols, and artillery fire. In February 1953 Van Fleet was succeeded as EUSAK commander by Lieutenant General Maxwell D. Taylor. Meanwhile, UNC air operations intensified to choke off communist supply lines and reduce the likelihood of communist offensives.

In November 1952 General Dwight Eisenhower was elected president of the United States on a mandate to end the war. With U.S. casualties running 2,500 a month, the war had become a political liability. Eisenhower instructed the JCS to draw up plans to end the war militarily including the possible use of nuclear weapons, which was made known to the communist side. More important in ending the conflict, however, was Stalin's death on 5 March 1953. As the armistice negotiations entered their final phase in May, Page 1159  |  Top of Articlethe Chinese stepped up military action, initiating attacks in June and July to remove bulges in the line. UNC forces gave up some ground but inflicted heavy casualties.

The chief stumbling block to peace was the repatriation of POWs. The North Koreans had forced into their army many South Korean soldiers and civilians, and thousands of them had subsequently been captured by the UNC. If all KPA prisoners were repatriated, many South Koreans would be sent to North Korea. Also, many Chinese POWs sought refuge on Taiwan (Formosa) instead of returning to the PRC. Truman was determined that no prisoner be repatriated against his will. This stance prolonged the war, but some U.S. officials saw a moral and propaganda victory in the Chinese and North Korean defections. The communist side rejected the UNC position out of hand.

Following intense UNC air strikes on North Korean hydroelectric facilities and the capital of Pyongyang, the communists accepted a face-saving formula whereby a neutral commission would deal with prisoner repatriation. On 27 July an armistice was signed at Panmunjom, and the guns finally fell silent.

Of 132,000 North Korean and Chinese military POWs, fewer than 90,000 chose to return home. Twenty-two Americans held by the communists also elected not to return home. Of 10,218 Americans captured by the communists, only 3,746 returned. The remainder were murdered or died in captivity. American losses were 142,091, of whom 33,686 were killed in action. South Korea sustained 300,000 casualties, of whom 70,000 were killed in action. Other UNC casualties came to 17,260, of whom 3,194 were killed in action. North Korean casualties are estimated at 523,400 and Chinese losses at more than a million. Perhaps 3 million Korean civilians also died during the war.

Anticommunist North Koreans wave Republic of Korea (ROK, South Korea) flags as they arrive in Seoul after being released from prisoner of war (POW) camps. The issue of repatriation complicated the armistice negotiations

Anticommunist North Koreans wave Republic of Korea (ROK, South Korea) flags as they arrive in Seoul after being released from prisoner of war (POW) camps. The issue of repatriation complicated the armistice negotiations, as many North Korean POWs desired to remain in South Korea. (National Archives and Records Administration)

The war devastated Korea and hardened the divisions between North and South. It was also a sobering experience for the United States. After the war, the U.S. military establishment remained strong. For America, the Korean War institutionalized the Cold War national security state. It also accelerated the racial integration of the armed forces, which in turn encouraged a much wider U.S. civil rights movement.

China gained greatly from the war in that it came to be regarded as the preponderant military power in Asia. This is ironic, because the Chinese Army in Korea was in many respects a primitive and inefficient force. Nonetheless, throughout the following decades exaggeration of Chinese military strength was woven into the fabric of American foreign policy, influencing subsequent U.S. policy in Vietnam.

The Korean War effectively militarized the containment policy. Before the war, Marshall Plan aid had been almost entirely nonmilitary. U.S. aid now Page 1160  |  Top of Articleshifted heavily toward military rearmament. The war also marked a sustained militarization of American foreign policy, with the Vietnam War a logical consequence.

Additionally, the Korean War solidified the role of the United States as the world's policeman and strengthened the country's relationship with its West European allies and the North Atlantic Treaty Organization (NATO). The war facilitated the rearmament of the Federal Republic of Germany (FRG, West Germany). It also impacted Japan and was a major factor fueling that nation's economy.

Militarily, the war was interesting for the extensive use of helicopters and jet aircraft. The conflict was also a reminder that airpower alone cannot win wars, and it revealed the importance of command of the sea.

No formal peace has ever been concluded in Korea. Technically, the two Koreas remain at war, and the 38th Parallel remains one of the Cold War's lone outposts.



Blair, Clay. The Forgotten War: America in Korea, 1950–1953. New York: Times Books, 1987.

Crane, Conrad C. American Airpower Strategy in Korea, 1950–1953. Lawrence: University Press of Kansas, 2000.

Ent, Uzal. Fighting on the Brink: Defense of the Pusan Perimeter. Paducah, KY: Turner Publishing, 1996.

Field, James A. History of United States Naval Operations: Korea. Washington, DC: Naval History Division, 1962.

Korea Institute of Military History. The Korean War. 3 vols. Seoul: Korea Institute of Military History, 1997.

Pierpaoli, Paul G., Jr. Truman and Korea: The Political Culture of the Early Cold War. Columbia: University of Missouri Press, 1999.

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Gale Document Number: GALE|CX2400700561

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