Based on Wikipedia: Korean War

On the morning of June 25, 1950, seventy-five thousand North Korean soldiers poured across the 38th parallel into South Korea. Within three days, they had captured Seoul. Within two months, they had pushed the South Korean army and its American allies into a tiny pocket in the peninsula's southeast corner, backs against the sea. The United States, caught flat-footed, scrambled to prevent the complete collapse of a country most Americans couldn't find on a map.

What followed was one of the bloodiest conflicts of the twentieth century—a war that killed more than a million soldiers and perhaps three million civilians, that reduced virtually every major city in Korea to rubble, and that introduced the world to the terrifying possibility of a direct military confrontation between nuclear-armed superpowers. And yet Americans would come to call it "The Forgotten War."

How did a peninsula half a world away become the site of such carnage? The answer lies in the peculiar circumstances that followed Japan's defeat in World War Two, and in the calculations of a young communist dictator who badly misjudged how the world would respond.

A Country Divided by a Line on a Map

Korea had been a Japanese colony for thirty-five years when World War Two ended in August 1945. The Japanese had ruled with an iron fist, suppressing Korean language and culture, conscripting Korean workers and soldiers, and exploiting the peninsula's resources for Japan's imperial ambitions.

When Japan surrendered, Korea's fate fell into the hands of the victorious Allies. And in the rush to accept Japanese surrenders across Asia, two American colonels were given a task that would shape history: divide Korea into occupation zones. They had thirty minutes.

Dean Rusk—who would later serve as Secretary of State during the Vietnam War—and Charles Bonesteel spread out a National Geographic map and looked for a logical dividing line. They chose the 38th parallel, a line of latitude that ran roughly through the middle of the peninsula. It had no historical, cultural, or geographic significance. It simply looked reasonable on the map, and it placed Seoul, the capital, in the American zone.

The Soviets, who had already entered Korea from the north, could have ignored this arbitrary line. Their forces were on the ground; American troops wouldn't arrive for another month. But Joseph Stalin, still pursuing cooperation with his wartime allies, ordered the Red Army to halt and wait.

What was meant to be a temporary administrative division hardened into something permanent. In the north, the Soviets installed Kim Il Sung, a thirty-three-year-old guerrilla fighter who had spent the war harassing Japanese forces in Manchuria. In the south, the Americans backed Syngman Rhee, a seventy-year-old nationalist who had spent most of his adult life in exile in the United States. Both men claimed to lead the legitimate government of all Korea. Neither would accept the other's existence.

The Road to War

The new Korean governments were born into violence. In the south, communist insurgents launched uprisings that would claim tens of thousands of lives before being crushed. On Jeju Island alone, government forces killed an estimated twelve thousand civilians while suppressing a leftist revolt. Along the 38th parallel, North and South Korean troops clashed repeatedly in what amounted to an undeclared border war.

Kim Il Sung watched these developments with growing confidence. He saw a South Korean military focused on counterinsurgency rather than conventional warfare. He saw an American military that had withdrawn most of its forces from the peninsula. And he believed—incorrectly, as it turned out—that the South Korean people would welcome his invasion as liberation.

In March 1949, Kim traveled to Moscow to persuade Stalin to support an invasion. Stalin said no. The timing wasn't right. American troops were still in South Korea, and China was still fighting its own civil war.

But by early 1950, the situation had changed. The Americans had withdrawn. Mao Zedong had won in China, creating a powerful communist ally on Korea's border. And Secretary of State Dean Acheson had given a speech that seemed to place Korea outside America's "defensive perimeter" in Asia.

Stalin gave his blessing. Mao, after some hesitation, agreed to provide support if needed. On June 25, 1950, the North Korean People's Army attacked.

Collapse and Counterstroke

The invasion was a masterpiece of military planning. North Korean forces, equipped with Soviet tanks and artillery, smashed through South Korean defenses with overwhelming force. The South Korean army, trained and equipped to fight guerrillas, had no anti-tank weapons capable of stopping the Soviet-made T-34s rolling south.

Seoul fell in three days. The South Korean government fled. American forces rushed from occupation duty in Japan were thrown into battle piecemeal and suffered devastating casualties. By August, the entire United Nations force—the Security Council had authorized military action while the Soviet representative was absent in protest over another matter—had been pushed into a tiny perimeter around the port city of Pusan in Korea's southeast corner.

It looked like the war was over. It wasn't.

General Douglas MacArthur, the legendary commander who had led Allied forces to victory in the Pacific, conceived one of the most audacious operations in military history. On September 15, 1950, American forces landed at Inchon, the port serving Seoul, two hundred miles behind enemy lines. The North Koreans had thought an amphibious landing there impossible—the harbor had extreme tidal variations that left ships stranded on mudflats if timing was off even slightly.

MacArthur's gamble paid off spectacularly. Within two weeks, Seoul was recaptured and the North Korean army was in full retreat, its supply lines cut. United Nations forces broke out of the Pusan Perimeter and began pursuing the shattered enemy northward.

China Enters the War

Here is where the war could have ended. Had the United Nations forces stopped at the 38th parallel—the original boundary—they would have accomplished their stated mission of repelling the invasion. But the temptation to finish the job proved irresistible.

MacArthur pushed north, capturing Pyongyang, the North Korean capital, in October. His forces advanced toward the Yalu River, which forms the border between Korea and China. He assured President Harry Truman that China would not intervene. "We are no longer fearful of their intervention," he declared.

He was catastrophically wrong.

China had been sending warnings through diplomatic channels for weeks. Mao Zedong could not accept the prospect of American troops on his border, especially with the United States refusing to recognize his government and continuing to support the defeated Nationalists on Taiwan. On October 19, 1950, hundreds of thousands of Chinese "volunteers"—technically not regular army troops, a legal fiction that allowed China to enter the war without formally declaring it—crossed the Yalu.

The Chinese struck with devastating effect. American and South Korean forces, spread thin across the mountainous terrain and unprepared for the harsh Korean winter, were overwhelmed. What followed was the longest retreat in American military history. In a matter of weeks, United Nations forces were pushed back below the 38th parallel. Seoul fell again in January 1951—the fourth time the city had changed hands in seven months.

The War Becomes a Stalemate

The front eventually stabilized near where it had started, roughly along the 38th parallel. A United Nations counteroffensive in the spring of 1951 recaptured Seoul for the last time and pushed the line slightly northward. But any hope of a decisive victory had vanished.

What remained was grinding attrition.

For the next two years, the armies faced each other across a fortified front line while negotiators at Panmunjom argued over the terms of an armistice. The talks dragged on, stalling repeatedly over the question of prisoner repatriation—many Chinese and North Korean prisoners did not want to return home, and the communists insisted on forced repatriation.

Meanwhile, the fighting continued. Soldiers died capturing hills that would be abandoned, then recaptured, then abandoned again. The names entered American military lore: Pork Chop Hill, Heartbreak Ridge, Old Baldy. American aircraft bombed North Korea relentlessly, destroying virtually every building of any size. General Curtis LeMay, head of the Strategic Air Command, later estimated that the bombing campaign killed twenty percent of North Korea's population.

MacArthur, who had publicly advocated for expanding the war to China and using nuclear weapons, was relieved of command by Truman in April 1951—a stunning moment that reasserted civilian control over the military but left MacArthur a martyr to those who believed the war should have been fought to total victory.

An Armistice, Not a Peace

The armistice was finally signed on July 27, 1953. By then, Truman had left office and Dwight Eisenhower, who had campaigned on a promise to end the war, was president. Stalin had died in March, and his successors were eager to reduce tensions with the West.

The armistice created a Demilitarized Zone, or DMZ, roughly four kilometers wide along the front line. It established the Military Demarcation Line that still divides North and South Korea today. It arranged for the exchange of prisoners. And it ended the fighting.

But it did not end the war. Technically, the Korean War has never ended. No peace treaty was ever signed. North and South Korea remain in a state of suspended hostility, separated by the most heavily fortified border on Earth.

The Human Cost

The numbers are staggering and still disputed. More than a million military personnel died—roughly half a million on each side, plus tens of thousands of Americans, Chinese, and soldiers from other countries. Civilian deaths may have reached two to three million in a peninsula with a population of about thirty million. Korea was devastated on a scale that rivaled the destruction of Germany and Japan in World War Two.

Both sides committed atrocities. South Korean forces massacred suspected communists; the most notorious incident, at a place called No Gun Ri, saw American troops kill hundreds of refugees they believed might be harboring enemy infiltrators. North Korean forces executed prisoners and massacred civilians accused of collaboration with the south. The bombing campaign against the north has been called one of the most intensive in history.

The war left Korea divided in ways that went far beyond geography. Millions of families were separated, unable to contact relatives on the other side of the DMZ. The division has now lasted more than seventy years—longer than the period Korea was unified before it.

Different Names, Different Memories

The war is remembered differently depending on where you are.

In South Korea, it's called the "625 War"—a reference to June 25, the date of the invasion. The emphasis is on North Korean aggression, American rescue, and national survival. June 25 is a day of remembrance.

In North Korea, it's the "Fatherland Liberation War," framed as a defensive struggle against American imperialism. North Korean history claims the South invaded first—a claim rejected by virtually all historians outside North Korea. The war is central to the regime's legitimacy and its narrative of perpetual threat from the United States.

In China, it's the "War to Resist America and Aid Korea," remembered as a heroic intervention that prevented American forces from reaching China's border. The war established the People's Republic as a major military power willing to confront the United States.

In America, it's the Forgotten War—sandwiched between the triumphant narrative of World War Two and the traumatic one of Vietnam. There's no Korean War memorial on the National Mall comparable to those for the other conflicts. For decades, veterans complained that their sacrifice went unacknowledged. The war's ambiguous outcome—neither victory nor defeat, just a return to the status quo ante—made it difficult to fit into national memory.

Legacy

The Korean War established patterns that would define the Cold War. It was the first major proxy conflict between the superpowers, with American and Chinese troops killing each other while Washington and Beijing avoided direct nuclear confrontation. It demonstrated that the Cold War could turn hot without triggering World War Three.

It transformed American foreign policy. Before Korea, there was serious debate about America's role in Asia and the size of its military. After Korea, the United States committed to containing communism globally, tripled its defense budget, and began building the network of alliances and bases that still defines its position in the world.

It hardened the division of Korea in ways that seemed temporary at the time but proved permanent. The DMZ, originally intended to be provisional, became the defining feature of the peninsula. Families that expected to be reunited after a few months or years were separated for lifetimes.

And it set the stage for everything that followed on the Korean Peninsula: the North's development of nuclear weapons, the South's transformation from impoverished dictatorship to wealthy democracy, the periodic crises that bring the world's attention back to a conflict that never really ended.

The Korean War began with a line drawn on a map by two American colonels working against a deadline. Seventy years later, that line remains—now marked by minefields, razor wire, and the constant possibility of renewed catastrophe.