With the Allies achieving victory in Europe and Japan, Korea, which had been occupied by Japan since 1910, would be placed under the temporary control of Russia and the United States. Korea was divided into two separate states at the thirty-eighth parallel with Russia holding the North and America holding the South (Uschan 36). As the relationship between Russia and America turned for the worse, leading to the Cold war, both attempted to gain as many allies as possible to support them (Bachrach 11). The American government felt it was their duty to stop the Soviet Union and issued the Truman Doctrine, which was a policy to fight Communism around the world (Uschan 27). Therefore the U.S involvement in the Korean War was justified as a way to prove that the U.S would not allow the Soviet Union to spread Communism without a fight.
After the events of World War II, the world was left with two major superpowers: the United States and the Soviet Union. Both sides of the conflict were balanced in power and a nuclear war was possible. Most fighting was indirect with neither nation sending armed forces at each other (Smith 30). Because these nations were the world’s superpower, they held a major influence on other world counties and used foreign nation’s conflicts as a way to challenge each other. America began to grow a fear of communism, known as the Red Scare which would only escalate as China fell to Communism (Helbertsam 587).
Around 1947, South Korea was one of the only areas in northeast Asia not under communist rule (Bunge 22). It began to appear that the Soviets were taking territory they were likely never to give up causing U.S. officials to realize that they had to make a claim on part of Korea (Uschan 25). While under the rule of the U.S and Soviets, North and South Korea were supposed to have an election that would reunite them sometime after World War II. However the Soviets prevented this and kept a hold on North Korea (Williams 41). Eventually the U.S and Soviets began to form separate groups in order to make a unified stance against each other such as NATO and the Warsaw Pact making the unification even more unlikely between the two sides of Korea.
On June 25, 1950 North Korea attacked South Korea; because the invasion was led by a Communist force it gave the U.