Korean War

Korean War (1950–1953).War came to Korea in 1950–53 as both a civil war on the Korean peninsula and the first military clash of the Cold War between forces of the Soviet Union and its Communist clients and the United States and its allies. It was, therefore, potentially the most dangerous war in world history.

Even before the war against Germany and Japan drew to a close in 1945, the United States and the Soviet Union assumed competing roles in shaping the postwar world. As the two undisputed victorious powers, they influenced the course of every political problem emerging from the debris of war. Unfortunately, hostility between the two powers increased at the same time and threatened the outbreak of another war, which after 1949 risked the use of atomic weapons.

The conservative forces eventually coalesced in the Republic of Korea under the leadership of President Syngman Rhee. A North Korean state, The Democratic People's Republic created by the Soviet Union and headed by Premier Kim Il‐sung, adopted a policy of opposition to Rhee's government and for unification of the Korean peninsula by armed force.

North Korean ground forces crossed the 38th Parallel into South Korea about 4:30 A.M. on 25 June 1950 (24 June Washington time). The main attack, led by two divisions and a tank brigade, aimed at Uijongbu and Seoul. In the central mountains, two North Korean divisions drove toward Yoju and Wonju and on the east coast, a reinforced division headed for Samchok.

In an emergency session on Sunday, 25 June, the UN Security Council (with the USSR boycotting because of the refusal to admit the People's Republic of China) adopted an U.S.‐sponsored resolution branding the North Korean attack a breach of the peace and calling on the North Korean government to cease hostilities and withdraw. The North Koreans did not respond to the UN resolution, so on the following Tuesday, the United States offered a follow‐up proposal that “the members of the United Nations furnish such assistance to the Republic of Korea as may be necessary to repel the armed attack and to restore international peace and security in the area.” Subsequently, the UN Security Council designated the president of the United States as its executive agent for the war in Korea. President Truman, in turn, appointed Gen. Douglas MacArthur as the Commander in Chief, United Nations Command (CICUNC). The military organization to wage war was in place.

Saving South Korea was certainly the most urgent UN war aim, but President Harry S. Truman also believed that the Soviet Union was the most dangerous threat to the western allies. The UN Command had to stop the North Koreans and eject them from South Korea by military means, no small task with the North Korean army rolling south and no UN troops on the ground. Moreover, while accomplishing this, the UN coalition had to avoid expanding the war into Asia and to Europe by provoking China or the Soviet Union to enter the struggle. So the Truman administration adopted additional, unilateral war aims designed to keep the violence confined to the Korean Peninsula, to keep the Soviets out of the war, to maintain a strongly committed UN (and NATO) coalition, and to buy time to rearm the United States and its allies.

At first, MacArthur had little choice in how to fight the North Koreans. Somehow he had to slow down their offensive sufficiently to give him time to mount a counter‐attack against their flanks or rear. His forces consisted of four undermanned and partially trained U.S. Army divisions comprising Gen. Walton Walker's Eighth Army, the South Korean army, then falling back in front of the enemy, an ill‐equipped U.S. air force, and growing naval U.S. strength. When the President ordered use of American troops, the Joint Chiefs of Staff (JCS) immediately sent additional army forces, marines, and air and naval forces to strengthen MacArthur's command. As these units began to deploy, MacArthur requested more reinforcements that included between four and five additional divisions.

In all, fifty‐three UN member nations promised troops to assist South Korea. Of all, the nations of the British Commonwealth were most ready to fight when war broke out. Great Britain, Australia, New Zealand and Canada were the first to send air, sea, and ground forces. Eventually UN allies sent over 19,000 troops to Korea. All were assigned to the U.S. Eighth Army.

MacArthur's first task was to block what appeared to be the enemy's main attack leading to the port of Pusan in the south. Rushing American ground and air forces from Japan to Korea, he hoped to delay the enemy column and force it to deploy, then withdraw UN forces to new delaying positions and repeat the process. With any luck, he could gain enough time to muster an effective force on the ground. For this task he ordered General Walker to send units to confront the enemy on the road to Pusan. Walker sent a small infantry force—Task Force Smith—to lead the way. While reinforcements were moving to Korea, MacArthur pushed the rest of Walker's Eighth Army (less the 7th Infantry Division) into Korea to build up resistance on the enemy's main axis of advance. With these forces and the South Koreans, Walker hoped to delay the enemy north and west of a line following the Naktong River, to the north, then east to Yongdok on the Sea of Japan. If forced to withdraw farther, he proposed to occupy the Naktong River line as the primary position from which Eighth Army would defend the port of Pusan.

With the main enemy force applying heavy pressure along the primary axis aimed at Pusan, Walker had to fight off two North Korean divisions, advancing around the west flank deep into southwest Korea. From there they could turn east and strike directly at Pusan. To head off this threat, Walker sent the 25th Infantry Division to meet the North Koreans west of Masan and stop them. In savage battle, the 25th slowed the North Koreans, and Walker pulled the Eighth Army and Republic of Korea Army (ROKA) behind the Naktong River line to defend Pusan.

Walker's retirement into the Pusan Perimeter fit MacArthur's plans perfectly. Now he could exercise close control over both the battle on the peninsula and preparations for an amphibious counterstroke, now planned for mid‐September. As reinforcements poured into Pusan and combat strength began to favor Walker, MacArthur started to shunt units, equipment, and individual replacements to Japan to rebuild a corps for use in the amphibious operation. With complete superiority of air power and growing strength in tanks, artillery, and infantry, MacArthur believed that Eighth Army and the ROKA could hold Pusan.

North Koreans launched violent, piecemeal attacks against the perimeter beginning on 5 August. By the end of August, the defenders had thrown back the first barrage of attacks, but a new onslaught began on the night of 31 August. This time the enemy hit simultaneously and even more savagely. American reinforcements had, however, greatly increased the combat power of the allies, and by 12 September the North Korean offensive had spent itself on all fronts against Walkers' skillful defense.

While the Eighth Army fought to hold Pusan, Mac Arthur readied the forces he had assembled in Japan to eject the North Koreans from Korea. He selected the port of Inchon near Seoul as the objective in spite of undesirable hydrographic characteristics. High tides, swift currents, and broad mud flats threatened the safety of an amphibious assault force. But Inchon also had some features that convinced MacArthur that the prize was worth the risk. The North Koreans, concentrated around Pusan in the south, would be vulnerable to an attack so far to the north, and the capture of Inchon would lead directly to the fall of Seoul. Because Seoul, the capital of South Korea, was the intersection of most of the major roads and railroads in South Korea, its capture would trap the North Koreans and force them to surrender or escape to the mountains, abandoning all their heavy equipment. MacArthur believed he could defeat the North Koreans in one decisive battle—the Inchon Landing.

Early in September, naval air forces struck targets up and down the west coast of Korea. As D‐day for Inchon approached, surface gunfire support ships began to add their weight. On 15 September, U.S. Marines of the newly formed X Corps successfully assaulted the port, paving the way for army troops that followed. In the ensuing campaign, North Korea forces fought bitterly to hold the capital. On September 28, Seoul fell, and by October 1, Marines held a line close to the 38th Parallel, blocking all roads and passes leading to Seoul and its port at Inchon.

Weakened by the heavy fighting of July and August, the Eighth Army could not at first break out of the Pusan perimeter. Finally, a week after X Corps landed at Inchon, the North Koreans began to waver. On 23 September they began a general withdrawal, and Eighth Army units advanced to link up with X Corps. MacArthur had won his battle and the UN was poised to exploit his success.

In retrospect, the turning point in the Korean War was the decision now made to cross the 38th Parallel and pursue the retreating enemy into North Korea. At President Truman's direction, the National Security Council (NSC) staff had studied the question and recommended against crossing the 38th because ejecting the North Koreans from South Korea was a sufficient victory. To this, the JCS objected. MacArthur, they argued, must destroy the North Korean army to prevent a renewal of the aggression. On 11 September—four days before the Inchon Landing—the president adopted the arguments of the JCS. Most importantly, Truman changed the national objective from saving South Korea to unifying the peninsula. After the UN Assembly passed a resolution on 7 October 1950 calling for unification of Korea, MacArthur was free to send forces into North Korea.

MacArthur's attack on North Korea never achieved the success of his earlier operations. Beginning 7 October, he sent the weakened Eighth Army in the main attack against the North Korean capital of P’yongyang without adequate combat support. As the supporting attack, he planned another powerful amphibious assault by X Corps to strike the east coast port of Wonsan on 20 October. Although the Eighth Army advanced rapidly toward P’yongyang against light resistance, the amphibious attack by X Corps was six days late landing in its objective area because mine sweepers had to clear an elaborate minefield. On 11 October, Wonsan fell to a South Korean corps, almost two weeks before the marines could land. P’yongyang fell on the 19 October.

After the capture of P’yongyang and Wonsan, allied troops streamed north virtually unopposed. Truman worried about possible Chinese intervention, but at a conference at Wake Island on 15 October, MacArthur belittled this possibility and was optimistic about an early victory. There was, however, little time to enjoy the successes of mid‐October. Beginning on the 25 October, a reinvigorated enemy struck the Eighth Army in a brief but furious counterattack. By 2 November intelligence officers had accumulated undeniable evidence from across the front that Chinese forces had intervened, and the Eighth Army had to stop its advance.

Chinese leaders had tried to ward off a direct confrontation with the Americans by warning the UN not to cross the 38th Parallel. American leaders interpreted these statements as bluff rather than policy. But they were wrong; Josef Stalin, the Soviet premier, asked Mao Zedong, the Chinese premier, to send Chinese forces to the aid of his clients, the North Koreans. After much deliberation, Mao decided to intervene. On 19 October Chinese Peoples Volunteers (CPV) crossed the Yalu River and massed some 260,000 troops in front of the UN Command.

After replenishing supplies, MacArthur's forces were ready. On 24 November the troops of the Eighth Army, unaware of the presence of massed Chinese forces, crossed their lines of departure. Within twenty‐four hours after the Eighth Army jumped off, the Chinese struck back, aiming their main attack at the South Korean ROKA II Corps on the army's right flank. Two days later the CPV hit U.S. X Corps as it advanced into the mountains of eastern Korea. Stunned and outnumbered, American and South Korean units recoiled, beginning a long retreat that ended in January 1951, only after the UN forces fell back south of the 38th Parallel and once again gave up the city of Seoul. X Corps fought its way back to the port of Hungnam on the east coast and then rejoined Eighth Army in the south.

During the first week of December 1950 when reports from the front were incomplete and most grim, President Truman met in Washington with Prime Minister Clement Attlee of the United Kingdom. Though initially far apart, Truman and Attlee, after four days of intense discussion, reached a compromise solution on Korea. They would continue to fight side‐by‐side, find a line and hold it, and wait for an opportunity to negotiate an end to the fighting from a position of military strength. Moreover, they reaffirmed their commitment to “Europe first” in the face of Soviet hostility toward NATO. In this way, the decision to unify Korea was abrogated and a new war aim adopted.

The most immediate military effect of the talks was to prevent MacArthur from exacting revenge for his humiliating defeat. The JCS limited his reinforcements to replacements, shifted the priority of military production to strengthening NATO forces, and wrote a new directive for MacArthur requiring him to defend in Korea as far to the north as possible. MacArthur disagreed with giving priority to Europe at the expense of the shooting war in Korea. He was outraged at the thought of going on the strategic defensive and fought against his new directive with all his might. Nevertheless, on 12 January 1951, the JCS sent him the final version of the directive, and the UN coalition had a new war aim designed to bring about a negotiated settlement.

Just two days before Christmas 1950, the command of the Eighth Army passed to Lt. Gen. Matthew B. Ridgway after Gen. Walker died in a truck accident. From his position on the Department of the Army staff in Washington, Ridgway came to the Eighth Army well informed of the strategic situation in Korea. He arrived at his new headquarters determined to attack north as soon as possible. Somehow he had to stop the retreat and turn the army around; until then the Eighth Army continued to withdraw. In early January 1951 UN forces gave up Seoul.

Finally, Ridgway's front line units began reporting light contact with the enemy. Sensing the opportunity to turn on the Chinese, Ridgway stopped the army on a line from P’yongt’aek in the west, through Wonju in the center, to Samch’ok on the east coast. When American divisions, withdrawn with X Corps, moved up to thicken the line in the lightly held center, Ridgway ordered his forces to patrol north and find the enemy. In a series of increasingly powerful offensives, he then sent the Eighth Army north: Operation Thunderbolt jumped off in January, Roundup in February (though a tactical setback), Killer in late February, Ripper in March, and Rugged in April. By this time, Ridgway's army had once again crossed the 38th Parallel where its forward units dug into strong defensive ground in anticipation of an enemy counteroffensive. Surprisingly, the shock came, not from the enemy as Ridgway expected, but from Washington, when MacArthur was dismissed by President Truman.

MacArthur's dismissal resulted from his rejection of Truman's policy. As Ridgway neared the 38th again, the position of military strength envisioned in the Truman‐Attlee conference had seemed near at hand. Truman took advantage of Ridgway's success to invite the Communists to negotiate a cease fire. After reading the text of Truman's proposed message, MacArthur broadcast a bellicose ultimatum to the enemy commander that undermined the president's plan. Truman was furious. MacArthur had preempted presidential prerogative, confused friends and enemies alike about who was directing the war, and directly challenged the president's authority as Commander in Chief. As Truman pondered how to handle the problem, Congressman Joseph W. Martin, Minority (Republican) Leader of the House of Representatives, released the contents of a letter from MacArthur in which the general repeated his criticism of the administration. The next day Truman began the process that was to end with Mac Arthur's being relieved from command on 11 April 1951.

After MacArthur's dismissal, Ridgway took his place as Commander in Chief, Far East and CINCUNC. Lt. Gen. James A. Van Fleet, an experienced and successful World War II combat leader, took command of the Eighth Army. On 22 April, as Van Fleet's Eighth army edged north, the CPV opened the expected general offensive, aiming their main attack toward Seoul in the west. The Chinese, numbering almost a half million men, drove Van Fleet once again below the 38th Parallel. On 10 May, the Chinese jumped off again after shifting seven armies to their main effort against the eastern half of the UN line. Taking advantage of the Chinese concentration in the east, Van Fleet attacked suddenly in the west, north of Seoul. The effect was dramatic; surprised CPV units pulled back, suffering their heaviest casualties of the war, and by the end of May found themselves retreating into North Korea. By mid‐June, UN forces had regained a line, for the most part, north of the 38th Parallel.

Regardless of UN success on the battlefield, ending the war turned out to be a maddeningly long process. U.S. planners knew that the Truman‐Attlee agreement made it unlikely that the war would end in a conventional victory. The UN allies had even adopted negotiating an armistice as a war aim. The time seemed right for the Chinese and North Koreans as well since they needed a respite from the heavy casualties suffered in the UN offensive. They agreed to meet with UN representatives when in late June 1951, the Soviets proposed a conference among the belligerents.

Negotiations were initially hampered by silly haggling over matters of protocol and the selection of a truly neutral negotiating site. Even so, on 26 July 1951 the two sides finally reached an agreement on an agenda containing four major points: selection of a demarcation line and demilitarized zone, supervision of the truce, arrangements for prisoners of war (POWs), and recommendations to the governments involved in the war. With an agreed agenda in hand, and Panmunjom—a town between opposing lines, suitable to hold talks—the negotiators began the lengthy process of debating each item. Handling POWs proved to be the most difficult problem on the agenda, but fixing the demarcation line was the most damaging. By dealing with the final position of the armies first, the UN negotiators blundered into an agreement that permitted the Communists to stalemate the battlefield and to wage a two‐year political war at the negotiating table.

At issue was a U.S. scheme seeking quick agreement on a demarcation line. On 17 November the UN delegation proposed the current line of contact as the demarcation line providing that all remaining agenda items were resolved within thirty days. The communists accepted the proposal on 27 November debated the remaining agenda items for thirty days, and then failed to reach agreement. They used the thirty days to create a tactical defense so deeply dug in that both sides had to accept a stalemate.

From that moment on, the battlefield changed to a static kind of war, more reminiscent of World War I than anything that had happened since. Beginning in the winter of 1951–1952, the war came to be defined by elevated sites named Porkchop Hill, Sniper's Ridge, Old Baldy, T‐Bone, Whitehorse, Punchbowl and a hundred other hilltops between the two armies. There followed a seemingly endless succession of violent fire fights, most of them at night, to gain or maintain control of hills that were a little higher and ridges that were a bit straighter. All of them, no matter how large the forces engaged, were deadly encounters designed to provide leverage for one side or the other in the protracted political battle going on at Panmunjom. In an historical age when technology enabled greater mobility than at any other time, tactical warfare in Korea went through a regression that can only be explained in terms of its close relationship to the negotiations. Constant pressure was its purpose, not decisive victory.

In Panmunjom negotiators plodded through the remaining agenda items. Supervising the armistice agreement was an extremely complex issue, but a compromise emerged that permitted rotation of 35,000 UN troops and supplies each month through specified ports of entry. In addition, both sides accepted Swedish, Swiss, Polish, and Czech membership on an armistice commission. Political recommendations to the belligerents were agreed in the astonishingly short period of eleven days. Both sides called for a conference to convene three months after a cease fire. At that time all political issues that had not been settled during the negotiations would be discussed.

What to do about prisoners of war was the major obstacle to final agreement. The UN Command wanted prisoners to decide for themselves whether or not they would return home. The Communists insisted on forced repatriation. To restore movement to the talks, the International Red Cross polled prisoners as to where they wanted to go. The results, announced early in April 1952, surprised everyone. Of 132,000 Chinese and North Korean POWs screened, only 54,000 North Koreans and 5,100 Chinese wanted to go home. The communist delegation was incredulous and accused the United Nations of influencing the poll. From that moment on, negotiations bogged down on the POW issue.

At about this time, May 1952, General Ridgway left Tokyo to become Supreme Allied Commander, Europe. Gen. Mark Clark, who had made his reputation during World War II in Italy, replaced Ridgway as CINCUNC and inherited a difficult situation. Unable to carry the war to the enemy in a decisive way and stalemated in the armistice talks, Clark—with the approval of the administration—finally ordered the UN delegation to walk out of Panmunjom on 8 October. With no one to talk to, the Communists hammered away at UN treatment of POWs and alleged UN violations of the neutral zones surrounding the negotiating site.

Over the fall and winter of 1952–53, three events broke the impasse. In November, Dwight D. Eisenhower won the election for the presidency, ushering in a new style of toughness toward the Communists—including discussion of using atomic weapons. In December, Clark read about an International Red Cross resolution calling for the exchange of sick and wounded POWs. In February 1953 Clark sent letters to the Chinese and North Korean leaders proposing that they exchange the sick and wounded. Before the Communists could respond, the third and perhaps most important event occurred: Josef Stalin died on 5 March 1953.

So achieving a cease‐fire was the result of a complex set of circumstances and interwoven pressures. Eisenhower's toughness increased the pressure on the battlefield. He believed that the Truman strategy was the only practical one, but still something ought to be done to give the Communists an incentive to reach agreement. He permitted Clark's aircraft to bomb dams in North Korea, flooding the countryside. He instructed the JCS to prepare plans for more intensive maneuver—even atomic warfare—should negotiations break down. He authorized movement of atomic delivery aircraft to the Far East and initiated training for low‐level attack with atomic bombs. And he sent John Foster Dulles, his Secretary of State, to India in April to let it be known that the United States was prepared to renew the war at a higher level unless progress was made at Panmunjom.

Clearly, Chinese leaders carefully considered these news signals, but it is conjectural to connect Ike's toughness and Stalin's death directly to the Communist agreement to end the war. Still, we do know that Stalin's death resulted in a deadly power struggle in the Kremlin that probably focused Soviet leaders on settling their internal problems rather than supporting a prolonged war. Moreover, East European states needed to be kept in line after Stalin's death, and something had to be done to restore deteriorating relations with the governments of China and North Korea, both of which had lost confidence in the Soviet government for not taking a more active part in the war.

On 26 April, negotiating sessions resumed at Panmunjom where a final solution to handling the remaining POWs took shape in the months that followed. Those who chose not to go home were to be turned over to a neutral repatriation commission. If they still did not want to go home, the neutral commission would release them to whichever government they chose. As the delegations wrapped up the details, it seemed that a cease‐fire was not far off.

While the UN worked diligently toward an armistice, South Korean President Syngman Rhee became obstructive. Rhee saw the rush toward an armistice as contrary to South Korea's best interest, and he did not trust the Communists should the UN Command pull out. So on the night of 18 June, Rhee ordered his guards on the POW compounds to release some 25,000 friendly North Koreans. The Communists cried “foul.” Eisenhower, feeling betrayed, was outraged. But in order to save the cease‐fire, he negotiated with the South Korean president, pledging a mutual security pact after the cease‐fire, long term economic aid, expansion of the South Korean armed forces, and coordination of U.S. and ROK objectives at the political conference. Though costly for the United States, the agreement secured Rhee's cooperation and cleared the way for an armistice.

While negotiating the final details of a truce, the Chinese communists sought one last military advantage. They mounted a limited offensive that was designed to push UN negotiators toward a settlement more agreeable to the Communist side; managed carefully, the offensive might also create the illusion of a peaceful settlement following a Communist victory. The attacks began on 10 June 1951 and by 16 June the UN line had been pushed back some 4,000 yards. Although some ground was recovered, fighting slackened as commanders of contending armies prepared to sign the truce. At 10 A.M. 27 July 1953, the darkest moment in Mark Clark's life, he signed the armistice documents to end the Korean War.

For a war intended to be limited, the human toll was staggering. Although Chinese and North Korean casualties are unknown, estimates of total losses amounted to almost two million, plus perhaps a million civilians. The UN Command suffered a total of 88,000 killed, of which 23,300 were American. Total casualties for the UN (killed, wounded, missing) were 459,360, 300,000 of whom were South Korean.

Nevertheless, limiting the war in Korea made a significant contribution to the history of the art of war. First, the Korean War demonstrated alternative strategies designed to gain national objectives without resorting to atomic war. For this reason, the Korean War is less about tactical evolution than about political goals, the strategy to achieve those goals, and the operational art designed to make the strategy succeed. Second, the war caused the U.S. government to arm the nation and its allies on a permanent basis and to bring its military force to a high state of combat readiness, prepared to respond quickly to any threat to national or alliance security. Never again would the United States find itself as ill‐prepared as it had been when the Korean War began.
[See also Korea, U.S. Military Involvement in; Korean War, U.S. Air Operations in; Korean War, U.S. Naval Operations in.]

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Roy K. Flint