Korean War In-Depth: From Beginning to Armistice

Korean War In-Depth: From Beginning to Armistice

The Korean War was the first and largest major battle of the Cold War, as proxies of the United States and Soviet Union took up arms to defend ideologies that clashed repeatedly over the next several decades. Fought between 1950 and 1953 (and still technically ongoing since the two sides never completed formal peace talks), it was war between North Korea, with the support of China and the Soviet Union, and South Korea, primarily supported by NATO and the United States.

Context of the Korean War

1. Post-WWII

Japanese troops in Korea, 1904

For centuries, Korea had been within the Chinese sphere of influence. In the 1870s, Japanese pressure began to force Korea away from China and toward more cooperation with Japan. In 1910 Japan annexed Korea outright, colonized it, and suppressed Korean culture. When Japan invaded China in 1937 they forced hundreds of thousands of Korean civilians to labor for the Japanese war machine throughout the empire. Meanwhile, the peninsula was stripped of much of its food and natural resources, forcing additional Korean immigration to Japan. As a result, about 25% of the casualties from the atomic bombings of Hiroshima and Nagasaki were Koreans. Japanese dominion over Korea ended with their acceptance of the Potsdam Declaration on August 15, 1945.

Allied Leaders at Potsdam

Map of Korea

The Japanese surrender and withdrawal from Korea created a power vacuum there. Weeks earlier at Potsdam President Truman had gotten Soviet leader Joseph Stalin to commit to declaring war on Japan, including attacks against the Japanese in Korea. With the Japanese withdrawing, nothing stood in the way of the Soviets taking over the entire peninsula. The Americans, trying to limit Russian gains, hastily proposed a division of Korea between Soviet forces in the north, and US forces in the south, with the 38th Parallel as the dividing line, picked by some junior officers who thought it looked roughly in the middle, where the peninsula narrowed. The US was lucky that Stalin agreed to the division. Even as Russian troops stopped at this artificial dividing line, American units were still a month away from arriving in Korea.

The US was totally unprepared for administering a free South Korea. The American in charge, Lt. General John R. Hodge, instantly disliked the Korean people. After accepting the Japanese surrender, Hodge put key Japanese colonial administrators back in charge, much to the dismay of the Koreans. When Hodge finally turned to Koreans for help in administering their own country, it was to those who had collaborated with the Japanese. Hodge refused to permit democratic elections, and at one point, martial law was declared.

2. North and South Korea in the Korean War

Syngman Rhee

The US eventually created a government, The Republic of Korea (South Korea), headed by Syngman Rhee, a nationalist who had fled the Japanese occupation decades earlier and had lived in exile mostly in the United States. He spoke English well, held 3 degrees from American universities, was anti-Communist, and he had not collaborated with the Japanese. But Rhee was a dictator who frequently arrested anyone who disagreed with him. Perhaps most problematic, Rhee frequently voiced his desire to invade the North.

Kim Il-Sung, 1950

Russian Troops in Korea

Meanwhile, the Soviets oversaw the creation of the communist Democratic People's Republic of Korea (North Korea), led by Kim Il-Sung, a former anti-Japanese guerilla fighter; a communist who had fought alongside the Russians at Stalingrad. The North Korean leader was even worse than his South Korean counterpart; Sung often had his political enemies executed.

By the end of 1948, the Korean peninsula was divided into two different nations, each with a leader who boasted about conquering the other, each supported by their ideological counterparts. The Soviets withdrew from North Korea, but US withdrawal from South Korea was repeatedly delayed to allow time for Rhee to improve South Korea's security situation.

By 1949, the US was disengaging from Korea in every way. On January 12, Undersecretary of State Dean Acheson told the press that South Korea was not a vital part of the US defense perimeter in Asia. By June only 500 American military advisors remained. Congress had become nervous that if too much aid were given to South Korea, Rhee would use it to invade the North. They sent light arms and armor, but withheld tanks and aircraft.

In January 1950, when aid to South Korea was up for renewal the US House defeated the bill, thereby cutting off all aid to South Korea. The fate of Korean aid had become intertwined with the desire by many Americans to get on with the business of their own lives. Having survived both the Great Depression and World War II, it was time to go to college on the G.I. bill, get a job, buy a home in the suburbs, and start families. Consequently, America's mighty war machine was being quickly disassembled.

By 1948, the US army was down to 677,000 men. By May 1949 it was at 630,000 and shrinking. By June 1950, with the military budget cut to the bone (supported by both Republicans and Democrats), there were only 591,000 men in the army. Additionally, its most-experienced troops were gone, and its equipment had been allowed to deteriorate. In short, the US was in no position to fight a war that no one in America wanted anyway.

These actions by the United States were a signal to Kim Il-Sung that he could unite the Korean peninsula without American intervention. Unlike their Southern counterparts, the North Korean military was disciplined, well-trained, and well-armed. It was made up of ten divisions, some 135,000 men. Many of its officers had fought alongside Mao Zedong's Communist Chinese forces during the Chinese Civil War. Most significantly, the Soviets had left behind 150 T-34 tanks, a model that had proved very effective against German armor in World War II. On June 25, 1950, after probing border forces for several weeks, Kim Il-Sung launched a full-scaled invasion across the 38th Parallel.

3. Phase 1 of the Korean War: North Korean Attack & UN Intervention (6/50-9/50)

Outmatched in every way, the South Korean army broke ranks and ran. Within a day, North Korean forces reached the outskirts of Seoul, the South Korean capital. In the ensuing panic, a key strategic bridge was blown up with the South Korean army on the wrong side of it, and while 500 people were still crossing it. Seoul was taken on the 28th.Even as the United Nations Security Council unanimously condemned the invasion, the Truman administration wrestled with what to do about it. Politically, Truman understood that to do nothing would open him up to attack from the conservative right. The President assumed that the Soviets were behind the attack, and seems to have believed that WWIII had begun. But he made up his mind that America would take a stand. Korea may have been of little to no strategic importance to the United States, but it had enormous psychological value. Communists had crossed an internationally recognized line. They would have to be “contained,” but Truman wasn't sure how.

Newspaper Headlines on Korea

Truman turned to the United Nations, where it just so happened that the Soviet Union was boycotting Security Council proceedings in protest of what they felt was UN preference for the Chiang Kai-Shek's government on Taiwan (the loser in China's civil war) over the mainland communist Chinese government. Without fear of a veto from the absent Soviets, the Security Council approved Resolution 83, recommending military assistance to South Korea. Shortly thereafter, the UN put these forces under American command.

UN Security Council Vote on Resolution 83


UN Ambassador Warren Austin to Truman, 6/27/50

The American commander who would lead the charge to contain communism was none other than America's most popular military figure, General Douglas MacArthur. 70 years old in 1950, MacArthur was one of the heroes of WWII. Although he had underestimated the Japanese military during the early stages of WWII, he subsequently displayed fine strategic skill and was especially good at predicting Japanese strategy.

He was a strong proponent of air power, preferring to pulverize fixed Japanese positions from the air rather than risking direct frontal assaults. He had been on-hand to accept the official Japanese surrender, and then had been in charge of US-occupied Japan. But MacArthur was also a supreme egotist who had spent so much time in the Pacific that he had come to see himself as both invincible and above any other authority. Truman had twice summoned him home to receive America's thanks for his role in the Pacific victory, but twice MacArthur had turned him down.

Truman rightly suspected that MacArthur was planning a triumphant return just in time to challenge the Democrats in the 1952 presidential election. To that end, MacArthur had quietly made strong ties with conservative Republicans in Washington. In the coming war, MacArthur would achieve his greatest success, and because of his flaws, his greatest failures as well. His ego would ultimately prove his undoing.

Truman address on Korea (7/19/50)


Truman address on Korea (7/19/50)

MacArthur in Korea

Right off the bat, MacArthur exceeded his authority by bombing North Korean airfields. But this did not stop the North Korean advance, and when MacArthur returned to Tokyo after inspecting the situation, he reported that the only way to stop them was to introduce American troops. Truman authorized the divisions MacArthur asked for, without seeking congressional approval, but he was wary of things escalating. He tried to downplay his actions. At a press conference on the 29th, he insisted that the United States was not at war. A reporter then asked, “Mr. President, would it be correct, against your explanation, to call this a police action under the United Nations? ” Truman replied, “Yes. That is exactly what it amounts to.”

Very few of the American troops sent to Korea were combat ready. Only one in six had even seen combat. The American G.I. had grown soft while serving in Japan as an occupation force. One of the top American generals in Korea later stated they had become “fat and happy in occupation billets, complete with Japanese girlfriends, plenty of beer and servants to shine their boots.”

Of the four American divisions stationed in Japan, the 24th Infantry Division was the least combat-ready. Yet they were extremely confident as they rolled into the theater of operations that the North Koreans would run away at the sight of American troops. This fallacy was based on judging the enemy through the lens of racism, the dangers of which the American should have learned from WWII. The North Koreans were good. They were disciplined, they used camouflage effectively, and they had no trouble leaving the main roads and hiking overland. They used battle tactics learned from the Chinese communists, which included infiltrating behind the American lines with small units that made the Americans think they were surrounded. They attacked at night and engaged in close combat in order to reduce the effectiveness of American air power.

On the morning of July 5, 540 men from the 24th Infantry Division moved north and took up a position north of Osan, where they soon encountered North Korean forces for the first time. The Americans attacked North Korean tanks, but their small mortars and recoilless rifles proved useless against the T-34. Some brave bazooka men closed to within 30 yards and fired, but that weapon too was ineffective. Only with a howitzer did they manage to knock out a few of the tanks, but the rest plowed right through them. When the order to retreat was given, many of the Americans threw aside their weapons and ran away. It took five days to round them all up. Of the 540-man task force, 180 were killed, wounded, or taken prisoner, all of whom had to be left behind. An American colonel later wrote about the pathetic condition of his fellow troops:

They'd spent a lot of time listening to lectures on the differences between communism and Americanism and not enough time crawling on their bellies on maneuvers with live ammunition singing over them. They'd been nursed and coddled, told to drive safely, to buy War Bonds, to give to the Red Cross, to avoid VD, to write home to mother-when someone should have been telling them how to clear a machine gun when it jams.

Now these troops were in a desperate fight for survival, in a place most Americans had never heard of and didn't want to hear about, in brutally hot weather with no water. Many of these soldiers became sick from drinking water directly out of muddy holes and paddies without first purifying it.

By the end of the first week two divisions had been badly mauled, suffering some 3,000 casualties. General MacArthur drew up a massive wish-list, most of which was approved, and some emergency equipment was rushed to Korea to help stop the North Korean tanks. But each time the 24th regrouped and took a stand, they were hammered again. By the end of the 3rd week they were at half strength. After a fierce three-day struggle, the Americans withdrew from Taejon. Although they had failed to stop the North Korean advance, they had delayed it long enough for the other American divisions to establish a defensive perimeter around Pusan further south.

It was here the Americans would make their last stand. But even as the Battle of Pusan Perimeter was about to being, there were signs that things were turning. Fresh troops and better equipment continued to arrive. The Americans cracked the relatively simple North Korean code, providing advanced notice of the enemy's battle plans. And by then the North Korean supply line was stretched thin.

Edward R. Murrow in Korea


Edward R. Murrow report on the Situtation in Korea, 8/1/50


Edward R. Murrow on Korea as a Testing Ground for Ideas, 9/6/50

Map of Phase 1: June 25-September 15, 1950

The Battle of Pusan Perimeter began in August and ended on September 15, during which the Americans withstood numerous North Korean attacks. The United States Air Force interrupted enemy movements by destroying 32 bridges and bombing convoys, and they hammered anything that might be of material value to the North Koreans. Meanwhile, United Nations troops and material continued to pour in. By late August, the Americans in the Pusan Perimeter had some 500 tanks, while the North Korean tank force had been reduced from 150 to 40.

By early September 1950, South Korean and UN Command forces outnumbered the North Koreans by 180,000 to 100,000. As MacArthur planned his next move, a special representative of President Truman's met with him in Tokyo to make sure he understood the administration's intent to not widen the war by provoking Chinese intervention in Korea or possibly a Chinese takeover of Formosa. MacArthur responded that if the Chinese were to do such a thing, he would “deliver such a crushing defeat it would be one of the decisive battles of the world-a disaster so great it would rock Asia, and perhaps turn back Communism.” He went on to say that he prayed nightly that the Chinese would try something.

4. Phase 2 of the Korean War: Escalation & Counterattack (9/50-10/50)

From the time that MacArthur had visited Korea, he began to conceive of a bold plan. He would undertake an amphibious landing behind North Korean lines, trap them, and then destroy them. Most military planners disagreed with him. The landing site he had chosen, Inchon, had no natural beaches. One sunken ship could block the whole harbor. The tides were difficult, and there was evidence the harbor had been mined. But MacArthur swayed them with a dramatic speech, and he got his way.

US Forces Land at Inchon

The landings at Inchon took place on September 15, 1950. Some 13,000 Marines went ashore and met little resistance. Only 21 Americans were killed, and the North Korean forces there were routed. The Americans moved quickly to re-capture Seoul, and to trap the North Korean army before it could retreat from Pusan, a hundred miles away, and get back across the 38th Parallel. This was MacArthur's finest hour. Practically overnight he had turned an inglorious American defeat into a stunning victory. The impact it had on his ego and power was incalculable. Whereas before he was thought by many political and military leaders as “untouchable,” now he was practically a god. But even though the Americans moved quickly, the North Koreans, now heading north at breakneck speed, were getting away. Some 40,000 had re-crossed the 38th Parallel.

One day after the initial landings at Inchon, September 16

Map of Phase 2: September 15-October 23, 1950

On October 1, 1950, South Korean and UN forces pushed past the 38th parallel into North Korea in hot pursuit. Although a few experts in the State Department warned about aggravating China to the north, no one really stopped to listen. Given the situation, even President Truman was reluctant to halt the operation for fear of providing further ammunition for Republicans to label him soft on Communism. MacArthur would be allowed to “finish the job” of Korean unification. The Chinese immediately signaled their disapproval.

As UN forces continued north, the Chinese became increasingly agitated. Chou Enlai, the Chinese Foreign Minister, relayed a message to Washington through the Indian ambassador, that if United States or UN forces, crossed the 38th Parallel, “China would send troops to the Korean frontier to defend North Korea.” The British especially expressed reservations about UN troop movements, but MacArthur dismissed them as appeasers. American forces crossed the 38th Parallel on October 7. Unbeknownst to the US, Mao Zedong then ordered his forces to start heading for the Korean border.

At this point, President Truman became nervous. He did not like the rumbling coming out of China, and he worried that UN supply lines were being stretched too thin. Of additional concern was the coming winter. He hastily arranged a meeting with MacArthur on Wake Island for October 15. Although the two men had never met, Truman did not have a high opinion of MacArthur, whom he had once described in a memo as “Mr. Prima Donna.”

MacArthur, a conservative Republican, didn't have a very high opinion of his commander-in-chief, a liberal Democrat. But their meeting went reasonably well. When Truman expressed concern about China intervening in the war, MacArthur assured him that the war was basically over. He even thought it possible that the Eighth Army could be home by Christmas. When Truman pressed a little harder on China, MacArthur dismissed the idea and claimed that if the Chinese crossed into North Korea and headed for Pyongyang, the North Korean capital, “there would be the greatest slaughter.”

Truman and MacArthur at Wake Island

5. Phase 3 of the Korean War: Chinese Intervention (10/50-12/50)

The Chinese army wasn't as well equipped as UN forces, but they marched 286 miles on foot in 18 days to get to the Yalu River. They carried minimal equipment, and about a week's supply of food-some rice, a little meat and fish-about ten pounds in all. They were trained not to move when aircraft were overhead, and they were extremely adept at camouflage. They knew much more about the American soldier than he knew about them, but they didn't know enough specifics about the troops MacArthur had under his command-how well he'd stand up in a fight, their weapons tactics, how they'd behave in the face of extreme adversity.

Chinese troops cross the Yalu River

As a way of gathering intelligence, the Chinese planned a series of limited attacks designed to reveal the enemy's strengths and weaknesses. That information would then factor into the all-out attack that would come later. Unaware of Chinese tactics or even their existence, the Americans headed directly for them. Though MacArthur had been strictly forbidden to stay away from the Yalu, he disobeyed. Once back at Tokyo, he ordered his two main forces to continue north to the Chinese border. The Joint Chiefs heard about this through an army backchannel, and told MacArthur that he had violated their instructions. MacArthur replied that he had military reasons for doing so.

South Korean troops first encountered small bands of Chinese on October 25 and took some prisoners. Shortly thereafter they were hit hard at Pukchin. The South Korean forces suffered heavy losses, but more prisoners were taken. Clearly, these were not North Korean soldiers. Their uniforms were different, and they spoke Chinese with a southern accent. Despite this evidence, MacArthur still refused to accept they had encountered Chinese.

Map of the early part of Phase 3: October 24-November 24, 1950

On the 29th, Fifth Regiment forces of the 24th Division under the command of John Throckmorton encountered stiff resistance about 40 miles from the Yalu. They took 88 prisoners, 2 of whom where Chinese. Throckmorton felt something ominous was in the air, and later said, “By that time I could feel the hair raising on the back of my neck.”

On October 30, the commander of X Corps interrogated 16 Chinese prisoners in South Korean custody. He then sent a message to MacArthur's headquarters warning that large units of Chinese infantry were in Korea, but nothing came of it.

Then on November 1, while maneuvering to destroy South Korean forces just north of Unsan, the Chinese accidentally encountered the US 8th Cavalry Regiment. UN intelligence had failed to detect them. The Chinese immediately launched a major three-pronged assault-from the north, northwest, and west-and overran the defensive flanks. The South Korean 6th Infantry Division on the right flank was quickly destroyed. Wave after wave of Chinese were sent against the Americans. When two of the three American battalions began to run out of ammunition, they retreated south. But Chinese forces had infiltrated behind UN lines and blocked the roads. At 2:30 a.m. they ambushed the retreating UN forces.

The Americans suffered heavy losses and only managed to escape by abandoning their vehicles and heavy weapons, forming small groups, and slipping through the Chinese lines on foot. Survivors reached the UN line on November 2. Meanwhile, another American battalion had been cut off in the north. At 3:00 a.m. Chinese commandos disguised as South Koreans launched a surprise attack on the mostly sleeping soldiers. The US 5th Cavalry Regiment tried several times to rescue them, but were driven back with heavy casualties. The trapped battalion endured several days of constant combat, and finally managed to break out of the trap on November 4.

Only 200 survivors made it back to the UN line. It was a devastating defeat for UN forces.

Amazingly, MacArthur (still commanding the overall action from Tokyo), still refused to accept that they had been attacked by Chinese rather than North Korean forces, that the war had fundamentally changed. Reality sunk in slowly.

On November 1 he said that frankly he didn't know whether his troops had encountered Chinese troops, and if they had, whether they represented the Chinese government.

On the 2nd, he admitted there were Chinese in Korea, and that they posed “a serious proximate threat.”

On the 4th, he concluded that the Chinese were in country in size and strength large enough “to threaten the ultimate destruction of my command.” It was quite a turnaround. He then claimed the battle a UN victory, and urged the international community to censure the Chinese government.

November 6, he announced that his troops would continue pushing north toward the Yalu River in order to probe the enemy's strength. But when MacArthur received reports that more Chinese troops were crossing bridges over the Yalu, he ordered them bombed-a direct violation of his orders to stay clear of the Chinese border. He sent a copy of the order to Washington and went to bed. Hours later, he was awakened by an urgent message from Washington directing him to rescind the order. MacArthur, enraged, drafted a reply in which he threatened to resign, but he was persuaded to rethink the message. Instead he prophesized doom if his orders weren't carried out:

Every hour that this is postponed will be paid for dearly in American and other United Nations blood… I trust that the matter be immediately brought to the attention of the President as I believe your instructions may well result in a calamity of major proportion for which I cannot accept the responsibility.

MacArthur's messages were so contradictory that the Joint Chiefs of Staff were shocked. First he had said there were no Chinese in Korea at all, and now suddenly total disaster was at hand. President Truman, when told of the disagreement about bombing the bridges, gave MacArthur the go-ahead, but now the general wanted permission to pursue Chinese aircraft across the border. MacArthur's superiors liked the idea, but the other UN partners unanimously said no, so Truman wouldn't permit it. MacArthur was furious.

Meanwhile, having completed their initial, intelligence-gathering offensives, the Chinese disappeared into the mountains to study the results and see what lessons they could glean. Other Chinese forces continued to cross the Yalu, but because of their superb organization and camouflage, continued to be undetected.

MacArthur mistakenly assumed the Chinese had withdrawn from the battlefield, that American air power had made it impossible for the Chinese to resupply their forces in Korea. He did not send out deep patrols to confirm his assumptions. On the 17th, he told the US ambassador to Korea that there were only 30,000 Chinese in North Korea. In fact, there were about 300,000. MacArthur ordered his forces to prepare for a major operation, which, based on remarks he made within earshot of the press, became known as the “Home-by-Christmas” offensive.

“Asiatics respect aggressive leadership,” he explained. This brief period in November, Secretary of State Dean Acheson later reflected in his memoir, represented the last possible moment to avoid the total disaster that seemed just beyond the horizon. The Chinese had clearly indicated their intentions. But, Acheson wrote, “We sat around like paralyzed rabbits while MacArthur carried out this nightmare.” On November 24, MacArthur flew to Korea and inspected the front lines. When he returned to Tokyo, he issued a communiqué that not only tipped off the Chinese that a major offensive was coming, but that the Americans had totally underestimated Chinese strength.

The “Home-by-Christmas” UN Offensive was launched on November 24, 1950. MacArthur divided his forces, sending the US Eighth Army under the command of General Walton H. Walker to advance in the northwest, while the US X Corps under the command of Major General Edward Almond attacked along the Korean east coast. South Korean forces advanced along the center. At first things went fairly well. Despite wind chills of 20 degrees below zero, the UN forces advanced some fifteen miles.

Map of the 2nd part of Phase 3: November 24-December 15, 1950

But the Chinese were waiting in ambush. Their goal was to utterly destroy MacArthur's forces. On November 25 they attacked along a 300-mile front. First, a column of Chinese infantry hit the Eighth Army's right flank, MacArthur's weakest point, totally annihilating South Korean forces and widening the gap between the Eighth Army and X Corps. Meanwhile, as the US Eighth Army made its way north on narrow, indefensible corridors that wound through mountains MacArthur had said were too rugged to shelter Chinese troops, the Chinese attacked with machine guns and mortars. It was a desperate moment.

But even as the US Eighth Army stalled in the mountains, Almond's X Corps on the right flank, unaware of the desperate situation to the west, continued forward along a 100-mile front. Almond ordered the 1st Marine Division, commanded by General Oliver P. Smith, to push rapidly along the 78-mile mountain road that connected the port city of Hungnam to the Chosin reservoir.

Almond believed there was no enemy out there. Smith, however, wasn't so optimistic. He advanced cautiously to allow time to close gaps in the ranks, and he established supply points and airfields along the way. Smith's caution would pay off. During their intelligence-gathering offensive weeks earlier, only one anomaly stood out. Several Chinese divisions had been soundly defeated by the 7th Regiment of US Marines. Now the Chinese had prepared something spec