1. The Korean War of 1950-1953 came about because Korea was divided against its will. Because the Soviet Union and United States had both occupied half of the country, they did not want their half to come under the influence of the other. In the 1940's most Korean people weren't too concerned with politics, they're number one concern was that Korea would be 1 country. The Korean War was a Civil War. In 1950, there were no Soviet or US soldiers in Korea. The leader of N.Korea and the leader of S. Korea both wanted to unify the entire country.
2. The North Attacked in 1950 because in 1949, with Mao's victory in the Chinese Civil War, tens of thousands of North Korea soldiers returned home. Also, the US seemed indifferent when the Chinese Nationalists were being defeated. At first, Kim Il Sung thought he could take over South Korea by way of an indigenous communist insurgency(much like the VC in South Vietnam). But many high level South Korean leaders were openly calling for an invasion of North Korea and at the same time, the US was making statements that indicated that it didn't care what happened to South Korea. So Kim Il Sung thought he could take over all of Korea before the US could react.
3. It was a turning point because it showed that the US would fight to defend its allies. It also meant that the US would rearm. It showed that conventional wars would still be fought and that Nuclear retaliation would not be America's first reaction on aggression. Because of the war, President Truman began America's involvement in Vietnam and also decided to defend Taiwan from a Communist invasion. Japan began to rebuild it's industrial strength and a few years later, West Germany was also reinstituted as a Western ally.
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