The Precursors and Implications of 
The Korean War
Asia History

Research Report
Web Resources


The Korean War began on June 25, 1950 when North Korean forces crossed the 38th parallel and invaded South Korea.  The war lasted 37 months until July 27, 1953.  The United States, backed by the United Nations, helped defend South Korea.In that time the US sent 172,897 troops to Korea where 54,246 were killed, 103,284 were wounded, 8,177 were reported as MIA (missing in action) and 7,190 were captured with 2,701 dying in captivity (that is more than one out of three).   Communist China helped bolster the North Korean forces with their causalities reported into the hundreds of thousands (p1 American POWs in Korea).

Historical Background

       Korea has the three great powers of East Asia as neighbors: Japan, China and Russia.  Korea traditionally looked to China for aid and support.  As China declined in the 19th century they were unable to continue to aid and support Korea, so Korea declined along with China.  Europeans were eager to open trade in the Far East, they succeeded in China and Japan, and turned their interests to Korea in the 1860's.  Koreans resisted the Europeans offers; they had seen the negative implications Europe had had on China.  Japan at this time was becoming a powerful imperialistic state and they were very interested in Korea.  Korea could no longer keep her doors closed to the outside world and in 1876, Korea signed a trade treaty with Japan; with this they could no longer deny treaties to other countries.  In the 1880's Korea signed treaties with the United States, Great Britain, and Russia.

    After the Sino-Japanese War of 1894-95 Korea was recognized as an independent country in the Treaty of Shimonoseki.   The war was fought between Japan and China with issues involving Korea; Japan wanted to influence the independent Korea.  Korean’s were anti-Japanese and since China was no longer there to aid them, Koreans turned to Russia.  This led to the Russo-Japanese war of 1902.  Japan won, which left no one else to help the Koreans.  The war ended at the Treaty of Portsmouth where Japan received the right to interfere in the internal life of Korea.  Japan went to work to “reform” and “modernize” Korea and turned Koreans into virtual slaves in their own land.  Korea was annexed to Japan in 1910.  Korean’s rebelled against the Japanese in 1919 but the rebellion was quickly and extremely brutally put down.  Japan ruled Korea very harshly.  Majority of Koreans were hewers of wood and drawer of water, but the more independent minded were imprisoned, tortured, and killed.  Many fled abroad into exile.  Syngman Rhee, the leader of South Korea during the Korean War, was one of these.  He was born in 1875, and was imprisoned between 1897-1904.  He fled to the United States where he studied and earned his Ph.D. from Princeton.  He returned to Korea after WWII.  Kim Il Sung, was another exile.  He left Korea and went to the USSR to study, he later became the leader of North Korea during the war.

    The Potsdam Conference took place in July of 1945.  In regards to the war in the Pacific, the USA agreed that they would fight up to the 38th parallel and occupy that territory and USSR would fight down to it and occupy that territory, thus splitting Korea.  Neither side considered the long-range consequences of dividing Korea; they were just interested in ending WWII.  The Koreans initially were happy to be rid of the imperialistic Japanese but now they had to contend with their country being divided with two world powers influencing their new and different political systems.

    The USA turned to Dr. Syngman Rhee to be the leader for South Korea and the USSR chose Kim Il Sung as the leader of North Korea.  With this division the stage was set for confrontation.

    The USA, USSR, Representatives from the political parties of South Korea, and Representatives from the political party (the Communist Party) of North Korea agreed to meet in Seoul in March of 1946; it was obvious from the start that there would be problems with this union.  The North and South disagreed on political philosophies and they each believed that they should control all of Korea.  Both sides began setting up different governments in their territory.  The North transitioned quickly with help from the USSR but still had some ideological differences.  The South transition was a bit more chaotic, even with the extra guidance from the USA.  Neither the USA nor the USSR understood what Korea wanted; and all three nations had different definitions of what independence meant.

    In September of 1947, the USA took the problem of Korean reunification and independence to the United Nations.  By November of 1947, the UN agreed that Korea should be an independent country and they voted to set up a temporary commission to bring that about.  The commission went to Korea in early 1948 but they were denied entrance into North Korea.  There was no recourse for these actions.  The committee recommended for South Korea to have free elections.  On August 15, 1948 Syngman Rhee became the first president of the Republic of Korea (South Korea).  Four months later the Republic was recognized by the UN as the only free state in Korea.  The Republic of Korea (South Korea) was given recognition only by western powers and the Peoples Democratic Republic (North Korea) was only recognized by the countries in the Eastern Block.  The USSR’s occupation forces left North Korea and the USA ended its military government in the South.  Both the USSR and the USA left behind governments that denounced the other and claimed to represent all of Korea and with leaders that were vehemently opposed to their counterpart’s philosophy.

Research Report

     General Douglas MacArthur, who later became the CINCFE (Commander in Chief of the Far East), in an interview in 1948, stated that the USA would defend the island line off the coast of Korea, but he failed to say that the USA would defend Korea.  Also in January of 1950, President Truman announced his opposition to defending Chiang Kai Shek on Formosa, but he failed to mention anything about Korea.  Again on January 12, 1950, Secretary of State Dean Acheson repeated President Truman’s views and again excluded South Korea from the US defense perimeter.  These statements were in accordance with NSC (National Security Council) 48/2.  Acheson’s speech derived its importance from the fact that authorities on the Korean War have tended to regard it as a green light to North Korea (p 35 A Short History of The Korean War).  So on Sunday June 25, 1950, North Korean forces crossed the 38th parallel and invaded South Korea.  Within a few days Seoul fell and the North Korean forces were sweeping the South Korean countryside.  The USA immediately went the UN on behalf of South Korea and asked for immediate assistance.  The UN Security Council (which the USSR was boycotting at the time) called upon North Korea to cease its aggressive action and for all the members of the UN to render assistance in achieving that end.  The UN also agreed to let the US run the war.

    The People’s Democratic Republic Army (North Korea) was a well trained first class outfit where as the Republic of Korea’s Army (South Korea) was not well trained, they had malfunctioning equipment, no tanks or heavy artillery, and only a few antitank weapons.  South Korea was being overrun by the North Koreans and South Korea needed help and quickly.  On June 29, 1950 General MacArthur flew over Korea to inspect the territory and the 1st Battalion of the 21st Infantry Regiment was in Korea by July 1, 1950.  With the help of the US forces they were able to maintain the Pusan Perimeter.  This was a race against the clock for both sides.   North Korea wanted push the South Koreans completely out of Korea before the UN could muster enough force to prevent it.  The UN/US forces wanted to back up South Korea long enough for outside intervention (other UN countries to send troops) to take effect.  The UN won the race.  The US and South
Korean forces were able to hold the Pusan perimeter until August 29, 1950 when the first ground forces from other members of the UN arrived.  By September 1, 1950 the UN had 180,000 men strengthening the perimeter with over 500 tanks in the area.  At that time the North Korean forces were 98,000 with fewer than 100 tanks left.  The UN forces set up a successful counterattack that lasted from September 1-10, 1950, and the North Koreans began to retreat.

    General MacArthur decided to try an ambitious amphibious operation and take Inchon, which is a port city on Korea’s western coast not far from Seoul. The Marines and the Navy did an excellent and careful job of caring out this operation.  They attacked on September 15, 1950, due to surprise and weakness of the enemy in the area they were successful with fewer than 200 causalities.  The Marines continued onto Kimpo Airfield, which was one of the few hard surfaced strips in Korea, and took it.  By September 25, 1950 they had liberated Seoul and quickly reached the 38th parallel.  This was a major victory for the UN forces and for General MacArthur.

  Now the UN had to decide what they should do and how far into North Korea should they go.  They had a few options, stop at the 38th parallel, and end the war, but this would return them to the same predicament as before.  They could continue into North Korea and advance past Pynongyang (North Korean capitol) and draw the new border between Sinanju and Wonsan.  This would leave North Korea without a means of making war in the future but would still leave a buffer zone between South Korea and China and the USSR.  The last option was to destroy North Korea and fight up to the Yalu River (northern border between Korea and China) thus unifying Korea.  This last option carried the risk of a massive reaction from either China or the USSR.  The UN went for the third option.  On October 25, 1950 the UN forces reached the Yalu River, China reacted and entered the war.  The leader of the Peoples Liberation Army (Chinese Communist Army) was General Chu Teh.  The Chinese forces were well trained, battle hardened troops that were very disciplined.  By November of 1950, the UN forces were taking heavy casualties and they were forced to retreat south.  MacArthur went on the deffensive and this was a tremendous blow to his ego.  The UN forces were being pushed back to the 38th parallel where a stalemate was reached.  China crossed the 38th parallel a few times and General Ridgeway made some advances for the UN forces but basically the troops were stopped at the 38th parallel.  “China had shown that it would not permit the Peoples Democratic Republic (North Korea) to be destroyed and the USA had shown twice that it would not permit the Republic of Korea (South Korea) to be destroyed” (P125 A Short History of the Korean War).

    Truman wanted to negotiate, he went to the UN to discuss different plans for peace, but by no means was this information public.  MacArthur took matters into his own hands and issued a public statement on March 24, 1951.  He first insulted the Chinese by saying that their military was overrated and if the UN had extended the war into their homeland the Chinese government would have collapsed, only then did MacArthur offer to open negotiations to end the war.  Truman was upset and relieved General MacArthur of his command on April 12, 1951.  General Ridgeway succeeded him as the CINCFE.

    By June 23, 1951 both sides agreed to negotiations.  On July 10, 1951 the first meeting took place at Kaesong, the ancient Capitol of Korea.  But again there were problems, neither side could agree on anything and the war continued.  A main issue regarded the return of POW (Prisoners of War) which was a dilemma that delayed the negotiation process.  There continued to be fighting along the 38th parallel for the next two years with both sides taking heavy casualties.   Finally on July 27, 1953, an armistice agreement was signed at Panmunjom, and the Korean War was over.

Historical Significance

    The Korean War had many implications.  First, it was the first time that the United Nations had really been tested where they took positive steps to resist aggression.  Second, it has kept Korea as a divided country.  The US forces have stayed in Korea, and US aid has been vital to South Koreas economic survival. America has been an incredible influence on South Korea; from religion to politics to culture to education.  To the point where in the early 90’s young student organizations formed that were Anti-American and resented America’s heavy hand in Korean life and their recent culture.  Korea’s relationship with Japan has turned into one of trade and competition.  Korea still has hurt feelings over wrongs done during Japan’s occupation of Korea but official relations were restored in 1965.  Korea relies on China’s market for trading their manufactured goods, Korea also is a competitor with China.

    Korea, as of March 2001, is still divided, with the North being Communistic, even after the USSR’s breakup in 1991; the South with their variations of the government that the US helped implement.  There have been discussions of reunification but neither side looks able to accept the other’s philosophy.  All in all the Korean War was an expensive war with tremendous loss of life where things ended up looking very similar when the war started.


Alexander, Bevin. Korea, The First War We Lost.  New York: Hippocrene Books, 1986.
Appleman, Lt. Col. Roy E. (AUS Ret.). Disaster In Korea.  College Park: Texas A&M University Press, 1989.
Cumings, Bruce.  The origins of the Korean War.  New Jersey: Princeton: University Press, 1990.
Gibney, Frank.  Korea’s Quiet Revolution.  New York: Walker and Company, 1992.
Hallion, Richard, P. The Naval Air War in Korea. Baltimore: The Nautical and Aviation Publishing Company of America, 1986.
Hastings, Max.  The Korean War. New York: Simon and Schuster Inc., 1987.
Heller, Fransis.  The Korean War A 25-Year Perspective. Lawrence: The Regents Press of Kansas, 1977.
Hoyt, Edwin P. The Day the Chinese Attacked, Korea 1950. New York: McGraw-Hill Publishing Company, 1990.
Jackson, Robert. Air War over Korea.  New York: Charles Scrubner’s Sons, 1973.
Spiller, Harry. American POWs in Korea.  London: McFarland and Company, 1998.
Stokesbury, James L. A Short History of The Korean War.  New York: William Morrow and Company, 1988.
Stuek, William.  The Korean War, An International History.  New Jersey: Princeton University Press, 1995.

Web Resources:   - Korean War Veterans National Museum  - for more information about the men who were MIA, POW's, or gave their life in the
               Korean War, this site also offers many interesting maps   - for more information on General MacArthur  - for more information on the casualties during the war   - for more information on the weapons of the Korean War

Webpage Created By: Annie Blaumueller