There are wars that define eras and wars that eras prefer to forget. The Korean War is both. Between 1950 and 1953, on a peninsula most Americans could not have found on a map, more than two million people died, the planet’s two nuclear superpowers squared off, and a geopolitical order was established that, seventy years on, remains in place. No peace was signed. There was no victory. There was no surrender. Only an armistice, a line on the map, and an uncomfortable silence that lasts to this day.
The Korean War is called “the forgotten war” because it was crushed between the epic of World War II and the trauma of Vietnam. It never got its Spielberg or its Coppola. It generated no countercultural movement, no crisis of national identity. It was a ferocious, bloody, inconclusive war that the United States chose to file away and the rest of the world barely registered. And yet few twentieth-century wars shaped the global strategic board as much as this one.
From Inchon to the Chinese Border: MacArthur and Hubris
It all began on June 25, 1950, when the North Korean army crossed the 38th parallel with some ninety thousand troops equipped by the Soviet Union. The invasion was swift. Seoul fell in three days. South Korean forces, poorly armed and worse trained, scattered southward. The United States, which had drastically reduced its military presence in Asia after 1945, found itself facing a crisis it had not expected.
Truman reacted quickly. He secured a UN Security Council resolution, possible only because the Soviet Union was boycotting the sessions and did not exercise its veto, and dispatched troops under United Nations colours. Command fell to Douglas MacArthur, hero of the Pacific War, de facto viceroy of occupied Japan, a figure of near-mythological proportions whose ego was matched only by his military talent. Or so it was believed.
By August 1950 the situation was desperate. UN forces and what remained of the South Korean army were pinned down in the Pusan Perimeter, a coastal strip in the southeast of the peninsula, holding off waves of North Korean attacks. The war seemed lost.
Then MacArthur played his card. On September 15, 1950, he launched an amphibious landing at Inchon, roughly a hundred miles behind enemy lines and fifteen miles from Seoul. The operation was technically absurd: Inchon’s tides were among the most extreme in the world, the approach channel was narrow and easy to mine, and the Marines would have to land directly against the harbour walls. The Joint Chiefs opposed it. Omar Bradley called it the worst place ever chosen for an amphibious landing. MacArthur insisted. “We shall land at Inchon and I shall crush them,” he told them.
He was right. Operation Chromite was a resounding success. The North Koreans, caught off guard, could not react. Seoul was recaptured on September 26. Enemy supply lines were severed. The North Korean army, trapped between Inchon and Pusan, disintegrated. Within weeks, of the roughly two hundred thousand troops that had invaded the South, barely twenty-five thousand managed to withdraw north of the 38th parallel.
Inchon was a stroke of military genius. It was also the beginning of the disaster, because it convinced MacArthur he was infallible.
Emboldened by the victory, MacArthur pressed to cross the 38th parallel and destroy the North Korean regime once and for all. Washington, euphoric over the success, gave in. On September 27 the Joint Chiefs authorised the advance north. Pyongyang fell on October 19. UN troops pushed towards the Yalu River, the border with China, as though the war were already won.
But China had warned, through its embassy in India, that it would intervene if UN forces crossed the 38th parallel. MacArthur dismissed the threat. Just as he had ignored the risks at Inchon, he now ignored the signals coming from Beijing. At the Wake Island meeting with Truman on October 15, MacArthur assured the president that the likelihood of Chinese intervention was minimal. Weeks later, hundreds of thousands of Chinese soldiers crossed the Yalu in silence, undetected, and fell on the UN columns like an avalanche.
Chinese Intervention and Trench Warfare
What followed was one of the most brutal military debacles in American history. In late November 1950, some two hundred and fifty thousand Chinese soldiers launched a massive offensive along the entire front. UN forces, strung out in columns separated by miles of frozen mountains, were hit at multiple points simultaneously. Temperatures dropped to thirty below zero. Soldiers froze to death in their positions.
The Battle of Chosin Reservoir became the symbol of those days. Roughly fifteen thousand Marines and Army soldiers found themselves surrounded by Chinese forces that outnumbered them overwhelmingly. The retreat to the port of Hungnam, through frozen mountains and under constant fire, was one of the hardest operations of the war. The Marines got out, but the cost was enormous, and the myth of quick victory died in the snows of North Korea.
Within weeks, everything gained after Inchon was lost. UN forces fell back below the 38th parallel. Seoul fell to the communists again in January 1951. MacArthur, who weeks earlier had spoken of reaching the Yalu, was now requesting authorisation to bomb Chinese bases in Manchuria and even considering, according to some accounts, the use of nuclear weapons.
Truman said no. The logic was impeccable from a strategic standpoint: open war with China could draw the Soviet Union into the conflict and trigger a third world war. MacArthur, who never had much regard for the subtleties of civilian politics, began publicly criticising the White House’s “limited war” policy. In March 1951 he issued a communiqué that openly contradicted Truman’s strategy. It was a direct challenge to civilian authority over the military, a foundational principle of the American republic.
On April 11, 1951, Truman relieved him of command. The decision provoked a political storm. MacArthur returned to the United States as a hero, delivered his famous address to Congress, “old soldiers never die, they just fade away,” and for a few weeks seemed capable of challenging the president himself. But Truman was right: limited war, frustrating as it was, was preferable to nuclear escalation. MacArthur faded, as promised. Truman preserved a principle worth more than any victory: civilian control of the armed forces.
Meanwhile, the war ground on. By May 1951, UN forces, now under General Matthew Ridgway, had stabilised the front near the 38th parallel. What followed were two years of positional warfare, trenches, and attrition that recalled the First World War more than the Second. Nameless hills were taken and retaken at appalling cost. Forty-five per cent of American casualties occurred after the armistice talks began in July 1951. Men were fighting to gain a negotiating position, not to win the war. It is hard to find a more cynical use of human sacrifice.
Armistice Without Peace: Seventy Years of Frozen Tension
The armistice was signed on July 27, 1953, at Panmunjom. Syngman Rhee, the South Korean dictator, refused to sign it, rejecting any agreement that did not reunify the peninsula under his rule. A demilitarised zone roughly four kilometres wide was established along the 38th parallel, conceding South Korea slightly more territory than it held before the war. After three years of fighting, millions dead, and the near-total destruction of both Koreas, the geographical situation was essentially the same as at the start.
Casualty figures are imprecise, as they tend to be in such cases, but the most widely accepted estimates speak of around 36,500 American soldiers killed, more than a hundred thousand South Koreans, between three hundred thousand and half a million North Koreans, and a figure for Chinese soldiers that varies enormously depending on the source, from the 183,000 Beijing acknowledged in 2010 to much higher numbers. Civilian deaths, as always, are the hardest to count: the most cited estimates range between one and a half million and three million. The proportion of civilians among total casualties was higher than in World War II and higher than in Vietnam. Korea was destroyed from end to end.
What sets the Korean armistice apart from other ceasefire agreements is that it never became a peace. Technically, the two Koreas are still at war. The demilitarised zone is the most heavily militarised border on the planet. The United States keeps roughly 28,500 soldiers in South Korea. Pyongyang developed nuclear weapons. Seoul became one of the richest and most dynamic cities in the world, twenty-two miles from a border where a million North Korean soldiers point south.
I have been to South Korea, and that proximity is something you feel. Seoul is a metropolis of twenty-five million people in its greater area, vibrant, modern, with an energy reminiscent of Tokyo, and yet a glance at the map is enough to grasp the absurdity of its situation: the most militarised border in the world is less than an hour’s drive away. It is not something that dominates daily life for South Koreans, who have spent decades living with this reality, but there is a background tension, a kind of forced normality you pick up on if you pay attention. South Korea built one of the most impressive economies on the planet literally within range of North Korean artillery.
The 1953 armistice resolved nothing. It froze a conflict. And frozen conflicts, as Russia demonstrated in Georgia, in Crimea, and in the Donbas, have the unpleasant tendency to thaw at the worst possible moment.
North Korea: The Impossible State Born of This Conflict
North Korea is probably the strangest political creation of the twentieth century. A Stalinist state frozen in time, ruled since 1948 by a single dynastic family, the Kims, with a personality cult that would make the pharaohs blush. A country of twenty-five million people that devotes a grotesque proportion of its economy to maintaining an army of over a million soldiers while its population goes hungry.
What keeps North Korea alive is not its ideology, nor its economy, nor the loyalty of its people. It is geography and geopolitics. The Pyongyang regime survives because it suits China that it survives. A North Korean collapse would mean a reunified Korea under the South Korean model, allied with the United States, with American troops directly on the Chinese border. For Beijing, North Korea functions as a buffer state, a manageable nuisance that is preferable to the alternative.
The North Korean nuclear programme, which led Pyongyang to carry out its first atomic test in 2006, changed the equation fundamentally. A regime that had been a geopolitical curiosity became an existential threat. North Korea today possesses a nuclear arsenal estimated at several dozen warheads and intercontinental ballistic missiles that, at least in theory, can reach the American mainland. It is the starkest demonstration of a principle every defence analyst knows: nuclear weapons are the great equaliser. It doesn’t matter how poor you are, it doesn’t matter how dysfunctional your state. If you have the bomb, nobody invades you.
The recent deployment of North Korean troops to Russia to fight in Ukraine adds another layer of complexity. Since the autumn of 2024, North Korea has deployed between ten and twelve thousand soldiers to Russia’s Kursk region, where they fought alongside Russian forces to recapture territory seized by Ukraine. In return, Pyongyang receives military technology, oil, and a strategic relationship that allows it to modernise its arsenal. The cooperation also includes the supply of millions of artillery shells and dozens of ballistic missiles. For an army that had not participated in a major conflict since the Korean War itself, the experience in Ukraine, with drones, electronic warfare, and trench fighting, is invaluable.
It is a fact worth pausing over: North Korean soldiers fighting in Europe, in a war between Russia and Ukraine, seventy years after their grandfathers fought the Americans at the 38th parallel. The threads of history are longer than they appear.
Implications for Taiwan and Frozen Conflicts
The Korean War established a pattern that recurs throughout Cold War and post-Cold War geopolitics: the frozen conflict. Two political entities separated by an armistice line, with no peace treaty, held in suspension by the balance of power among great powers. Korea is the oldest and most extreme example, but not the only one.
Taiwan is the most obvious analogy and the most dangerous. The island, governed by the Republic of China since 1949, exists in a legal and strategic limbo that closely resembles Korea’s before 1950. China claims it as its own. The United States maintains a position of “strategic ambiguity” regarding its defence. Taiwan is not formally a state recognised by the UN or by most countries, yet it functions as a prosperous democracy with a highly sophisticated economy, and its semiconductor industry is vital to the global economy.
The lesson of Korea for Taiwan is twofold. First, that frozen conflicts can heat up without warning. In June 1950, nobody expected a war in Korea. Secretary of State Dean Acheson himself, months earlier, had left Korea outside the American defensive perimeter in Asia in a public speech. It is possible that signal was read by Stalin and Kim Il-sung as a green light. Strategic ambiguities are useful until they aren’t.
Second, that the commitment of the United States is the decisive factor. South Korea exists today as a free democracy and an economic power because the United States chose to fight for it in 1950 and kept troops on its soil for seven decades. Without that presence, without that guarantee, South Korea probably would not exist. The same logic applies to Taiwan. The question is not whether China has the military capability to invade the island. The question is whether the United States has the will to defend it. As long as that will exists, or as long as Beijing believes it exists, the peace holds.
There is an uncomfortable truth the Korean War illustrates with brutal clarity: peace is not maintained by good intentions or by multilateral bodies. It is maintained by military power and by the willingness to use it. The UN Security Council was able to authorise the intervention in Korea only because the Soviet Union was absent and could not veto it, an accident that was never repeated. The security architecture that protects South Korea, Taiwan, Japan, and a good part of the free world does not rest on international law. It rests on American military capability and on the network of alliances Washington built after 1945.
The Korean War was the first demonstration of that logic in the nuclear age. It was also the first war in which the United States fought not to win but to avoid losing, to contain, to hold a balance. It was a war without a victory parade, without a surrender on the deck of a battleship. It was, in a sense, the first modern war: ambiguous, limited, politically frustrating, militarily inconclusive.
Seventy years later, that war is still not over. The border is still there. The soldiers are still there. The nuclear weapons are there. And the question nobody can answer is the same one as in 1950: what happens when a frozen conflict thaws?