Study Guide

The Korean War Timeline

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Dec 19, 2019

Japan Declares Korea Protectorate

Japan declares a protectorate over Korea.

Dec 19, 2019

Japan Annexes Korea

Japan formally annexes Korea as a colony. Japanese investments begin to flow into the new colony, turning it into a source of industrial and agricultural wealth for Japan.

Jul 1, 1945

Potsdam and Korea

By mutual agreement at the Potsdam Conference, the United States and Soviet Union—allies in World War II—make plans to jointly occupy Korea following the defeat of Japan. Soviet troops will occupy the northern portion of the country and the United States will take the southern half, with the 38th parallel serving as the dividing line between the two zones of occupation.

Aug 10, 1945

Russians Arrive in Korea

In the last days of World War II, Russian troops begin moving into northern Korea. There are not yet any American troops on the peninsula.

Aug 15, 1945

V-J Day

Japan surrenders to the Allies, officially ending World War II.

Aug 26, 1945

38th Parallel

Soviet forces complete their occupation of northern Korea, halting their southward advance through the country exactly at the 38th parallel, as agreed at the Potsdam Conference. The Soviets will wait patently for several weeks as the Americans hastily organize their own occupation of southern Korea.

Sep 9, 1945

U.S. in Seoul

American forces finally reach Seoul, where they accept the Japanese surrender of southern Korea.

Mar 5, 1946

Iron Curtain Speech

British Prime Minister Winston Churchill gives his famous "Iron Curtain" speech at a college graduation in Fulton, Missouri: 

"From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent. Behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia; all these famous cities and the populations around them lie in what I must call the Soviet sphere, and all are subject, in one form or another, not only to Soviet influence but to a very high and in some cases increasing measure of control from Moscow."

Mar 12, 1947

Truman Doctrine

In a speech later remembered as the "Truman Doctrine," President Harry S. Truman pledges American assistance to any nation in the world threatened by communism, officially establishing the worldwide containment of communism as a vital American national security interest.

Sep 1, 1947

U.S. to Leave Korea

American forces begin to prepare to withdraw from Korea, hoping to leave the South as an independent state under the leadership of the pro-American conservative Dr. Syngman Rhee.

May 1, 1948

Syngman Rhee Elected

South Korea holds its first elections. With the communists and other anti-Rhee factions boycotting the vote and challenging its legitimacy, Dr. Syngman Rhee wins easily, positioning himself to become South Korea's first president.

Jul 26, 1948

Truman Desegregates Military

President Truman desegregates the U.S. Armed Forces by signing Executive Order 9981. The order states, "It is hereby declared to be the policy of the President that there shall be equality of treatment and opportunity for all persons in the armed services without regard to race, color, religion, or national origin." 

In order to implement this policy, the order also establishes the President's Committee on Equality of Treatment and opportunity in the Armed Services.

Aug 1, 1948

Republic of Korea

Dr. Syngman Rhee's South Korean regime proclaims itself the independent Republic of Korea, denying the legitimacy of North Korea and claiming sovereignty over the entire Korean Peninsula.

Sep 1, 1948

Democratic People’s Republic of Korea

Communist North Korea, led by Kim Il Sung, proclaims itself the Democratic People's Republic of Korea, denying the legitimacy of South Korea and claiming sovereignty over the entire Korean Peninsula.

Jan 12, 1950

Dean Acheson Delares Defensive Perimeter

In a speech, Secretary of State Dean Acheson pledges that the United States will fight to defend all territory within its "defensive perimeter," which he defines to include Japan, and the Philippines—but not Korea. Soviet leader Joseph Stalin misinterprets this speech to mean that he can green-light North Korean leader Kim Il Sung's "liberation" of South Korea with little risk of intervention by the United States.

Mar 1, 1950

Stalin Approves Korean Invasion

North Korean leader Kim Il Sung goes to Moscow to ask Soviet leader Joseph Stalin's permission to invade South Korea and begin the Korean War. Stalin gives the green light because he believes the United States has little interest in Korea.

May 1, 1950

1950 Korean Election

President Syngman Rhee's unpopular conservative faction loses its control over the South Korean assembly when voters elect anti-Rhee moderates to office in the 1950 elections. Rhee remains president.

Jun 25, 1950

North Korea Invades

Communist North Korean troops launch a full-scale invasion of the South, beginning the open military phase of the Korean War. North Korean tanks and infantry surge across the 38th parallel into South Korean territory, quickly overrunning the defensive positions of overmatched South Korean forces. The communists continue their southward advance, meeting little resistance in the countryside.

Jun 25, 1950 - Sep 1, 1950

Syngman Rhee and the Summer of Terror

In response to North Korea's invasion of his country, South Korea President Syngman Rhee orders his military and special police forces to eliminate the threat posed to his regime by political prisoners and leftist dissidents, whom he fears will join forces with the communist invaders. In the so-called "Summer of Terror" that follows, Rhee's forces will execute more than 100,000 people.

Jun 26, 1950 - Jun 27, 1950

Truman Meets at Blair House

While the situation in Korea rapidly deteriorates, President Truman convenes two days' worth of high-level meetings at Washington, D.C.'s Blair House (his temporary residence while the White House undergoes renovations). In consultation with top officials of the State and Defense Departments, Truman makes the critical decision to offer military aid to South Korea without seeking an official declaration of war from Congress.

Jun 27, 1950

U.S. and UN Condemn North Korea

In the morning, President Truman issues a statement announcing to the American public the decision made at Blair House on the 25th and 26th of June: "I have ordered United States air and sea forces to give the Korean Government troops cover and support." 

In the afternoon, the United Nations Security Council—temporarily being boycotted by the Soviet Union—passes an American-drafted resolution condemning North Korea as the aggressor in the conflict and calling on all members states to "furnish 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." 

Though Truman will cite the UN resolution as justification for his intervention, he in fact makes his decision to commit American forces to the conflict before the UN request of assistance to the South Korean regime.

Jun 28, 1950

North Korea Captures Seoul

North Korean forces capture the South Korean capital city of Seoul.

Jul 4, 1950

Battle at Osan

American ground troops go into battle against Northern Korean forces at Osan (just south of Seoul on the western side of the peninsula). The Americans, expecting an easy victory over an overmatched foe, are stunned to discover that the North Korean army will be a formidable adversary. The Americans suffer 150 casualties in the battle and fail to halt the North Koreans' southward advance.

Jul 21, 1950

North Korea Advances to Daejeon

Communist forces continue their southward advance through the Korean peninsula, driving American forces back to Daejeon, 100 miles south of Seoul.

Aug 4, 1950

Retreat to Pusan Perimeter

American and South Korean forces end more than a month of retreat by establishing, finally, a stable defensive line outside the city of Pusan, at the far southeastern tip of the peninsula. The shattered remnants of the South Korean army and the entire American force in Korea crowd into the tiny area behind the so-called Pusan Perimeter; the entire rest of the country, more than 90% of Korea's land area, is now under communist control. 

Over the next six weeks, North Korean forces will launch a series of ferocious assaults against the Pusan Perimeter, hoping to achieve a decisive victory to end the war. But the Americans hold the line, buying time for General MacArthur to organize a counterattack.

Aug 4, 1950 - Sep 16, 1950

MacArthur and the Inchon Landing

General MacArthur orchestrates one of the great tactical victories in American military history, a massive amphibious landing of thousands of soldiers and Marines at Inchon, a city located along Korea's west coast not far from Seoul, hundreds of miles behind enemy lines. MacArthur's audacious Inchon Landing catches the North Koreans completely by surprise, allowing the Americans to cut vital lines of supply to the communist troops farther south at Pusan, forcing them into a desperate retreat back to the North. 

It will take only ten days after the Inchon Landing for the Americans to recapture Seoul, and only a few weeks to regain control over all territory south of the 38th parallel. By the end of September, MacArthur will be confident that he is well on the way to winning the war.

Sep 27, 1950

Truman Authorizes Advance

President Truman authorizes General MacArthur to order his forces to pursue the retreating North Koreans across the 38th parallel, into North Korean territory. This decision marks a fundamental enlargement in American war arms, now expanded from merely rescuing South Korea to rolling back the communist regime in North Korea. Truman's orders direct MacArthur to keep pushing northward as long as he doesn't encounter Soviet or Chinese opposition and he remains confident of victory.

Oct 20, 1950

U.S. Reaches Pyongyang

The U.S. First Cavalry Division enters Pyongyang, the North Korean capital. The jubilant American soldiers are convinced that victory in the broader war is near, taking bets on exactly when they will be able to ship out for home.

Oct 25, 1950

Chinese Cross the Yalu

Communist Chinese forces, who have been secretly infiltrating Korean territory by slipping across the Yalu River under cover of darkness, ambush a South Korean regiment high in the mountains of North Korea. This is the first of many Chinese victories over unprepared and overstretched South Korean and American units over the winter of 1950 to 1951.

Nov 1, 1950

China Enters Korean War

Chinese leader Mao Zedong, fearful of the consequences of hostile American forces taking up positions along his country's border at the Yalu River, orders hundreds of thousands of Chinese soldiers into battle in Korea. The massive Chinese intervention into the Korean conflict catches American military leaders completely off guard, leading to a series of crushing defeats. American prospects in the Korean War deteriorate rapidly, as hopes of imminent victory give way to a desperate struggle to avoid defeat.

Dec 19, 2019

Korean War Stalemate

In the first half of 1951, the war in Korea begins to settle into stalemate. The year begins with surging communist forces driving American and South Korean troops into a desperate southward retreat. By springtime, however, American forces organize a successful defensive line not far from the 38th parallel, halting the Chinese advance. Both sides launch a series of offensives aimed at breaking through the increasingly entrenched lines of battle, but neither can make much headway.

Feb 1, 1951

Peace Talks Drag

With the Korean War seemingly settling into a bloody stalemate, the United Nations passes a resolution calling for a negotiated end to the conflict. The first peace talks between American, Chinese, North Korean, and South Korean negotiators will begin in August 1951, but will drag on for nearly two years. More than half of the 36,000 American soldiers killed in the Korean War will lose their lives after the beginning of the peace talks.

Apr 1, 1951

Truman to Fire MacArthur

The Senate passes legislation reaffirming the scope and purpose of a unified NATO and authorizes President Truman to send four American divisions to be stationed in Europe. Truman now feels free to fire MacArthur.

Mar 24, 1951

MacArthur Rebukes Truman

General MacArthur—frustrated by the Truman administration's strategy of limited war in Korea, which precludes him from attacking China directly or making use of nuclear weapons—makes an unauthorized public statement threatening the Chinese with imminent destruction if they do not withdraw from Korea. 

In Washington, President Truman and his joint chiefs of staff conclude that MacArthur has become dangerously insubordinate, liable to do or say something so provocative it will drag the United States into a wider war. Though Truman believes MacArthur will soon have to be fired, he doesn't yet feel he can take such a dramatic action against the popular general.

Apr 5, 1951

Douglas MacArthur Writes Congress

House Minority Leader Joseph W. Martin, a Republican from Massachusetts, reads a letter from General MacArthur. It's a private letter but MacArthur has given no instructions with regard to confidentiality, so Martin reads it into the Congressional Record for the benefit of the American people. 

In the letter, MacArthur recommends "meeting force with maximum counterforce" in Korea—comments construed to mean that the general favors the use of Chinese nationalist troops from Taiwan in the fighting, an action which would almost certainly lead to full-scale war with communist China and a possible world war. The Truman administration vehemently opposes such an expansion of the war.

Apr 6, 1951

Truman and Cabinet Discuss MacArthur

Following the public announcement of General MacArthur's belligerent comments, President Truman calls a meeting with Cabinet members to discuss the situation.

Apr 9, 1951

Matthew Ridgway Replaces Douglas MacArthur

President Truman and his advisors agree that the time has come to relieve General MacArthur from his command. General Matthew Ridgway will replace MacArthur as Supreme Commander in Korea.

Truman Fires MacArthur

The White House makes a special late-night announcement that General Douglas MacArthur has been relieved of his duties. MacArthur learns of his firing when one of his aides hears the radio broadcast at headquarters and telephones the general's residence in Tokyo to tell him.

Truman Speaks to Nation

In a statement broadcast nationally on radio and television, President Truman explains why he has relieved General MacArthur of his position as Supreme Commander for the Allied Powers. He doesn't discuss the General's comments or the constitutional issues pertaining to MacArthur's insubordination, but instead stresses the American goal in Korea to avoid a third world war, and states that "a number of events have made it evident that General MacArthur did not agree with that policy."

MacArthur Praised

General MacArthur returns to the United States, arriving in San Francisco to a hero's welcome. In these early days of the Truman-MacArthur dispute, the American people seem to be siding with MacArthur. Truman's public-approval ratings plummet below 25%.

Apr 18, 1951

MacArthur Addresses Congress

General MacArthur, addressing a joint meeting of Congress, receives a standing ovation from a bipartisan majority of the legislators packed into the House chamber. Only a few Democrats loyal to President Truman don't stand to applaud the general. MacArthur, speaking from a prepared text, reiterates his belief in the need to take any measures necessary to achieve total victory in Korea. Over the course of his 34-minute speech, he's interrupted by applause 30 times.

Apr 19, 1951

MacArthur Receives Ticker-Tape Parade

In New York City, an estimated 7.5 million people turn out to cheer for General MacArthur as he parades through the city in the back of an open Chrysler. The streets are so thronged with supporters that it takes MacArthur's motorcade more than seven hours to cover the 19.5-mile parade route, from the Battery to St. Patrick's Cathedral and back again.

May 3, 1951 - Jun 25, 1951

MacArthur Hearings

The Senate Foreign Relations and Armed Services committees begin joint hearings to investigate the dismissal of General MacArthur. Republican congressmen demand the hearings in hopes of vindicating their fallen hero, but the subsequent testimony ends up discrediting him more than restoring his reputation. 

Through more than a month of hearings, MacArthur's arrogance, recklessness, and insubordination are clearly revealed. Most Americans come to believe that Truman was correct to remove MacArthur from command. MacArthur, his reputation badly damaged by the hearings, will make a failed bid for the Republican presidential nomination in 1952, then largely fade away from any prominent involvement in public affairs.

Nov 4, 1952

Eisenhower Elected

In the American presidential election, Republican Dwight D. Eisenhower receives more votes—almost 34 million—than any previous candidate in American history. Eisenhower, a retired general and World War II hero, has built his campaign largely around a promise to pursue an honorable truce in the Korean War to allow the withdrawal of American combat forces as soon as possible.

Jul 27, 1953

Korean War Armistice

After nearly two years of negotiations, diplomats from the United States, North Korea, and China reach agreement on an armistice to end the "UN peace action" in Korea without a formal peace treaty. Both sides claim victory, and Korea remains divided at the 38th parallel.

Oct 1, 1953

Peace Villiage Talks Fail

Diplomats from China, North Korea, and the United States convene in Panmunjom—the so-called "Peace Village" located on the border between North and South Korea at the 38th parallel—to plan a political conference to reach agreement on a final, permanent peace treaty to end the war. Even this preliminary planning breaks down amidst angry accusations and counter-accusations from both sides.

Apr 1, 1954

Geneva Talks Fail

At a high-level conference in Geneva, representatives from the United States and China fail to resolve the Korean issue. The armed stalemate at the 38th parallel will continue indefinitely.

Dec 19, 2019

Mass Graves Discovered

A severe typhoon uncovers a mass grave holding victims of the 1950 "Summer of Terror," South Korean President Syngman Rhee's campaign of executions against leftists and other potential political dissidents. It becomes increasingly difficult for the South Korean government to deny that the killing ever occurred.

Dec 19, 2019

South Korea Truth and Reconciliation

The South Korean government, having undergone far-reaching democratic reforms in the late 1980s and 1990s, establishes a Truth and Reconciliation Commission to investigate its own role in the 1950 "Summer of Terror" killings.

Jan 1, 2008

South Korea Apologizes for Summer of Terror

South Korean President Roh Moo-hyun, citing the findings of his Truth and Reconciliation Commission, formally apologizes for the atrocities committed during the "Summer of Terror" in 1950, calling them "illegal acts the then-state authority committed."

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