The Korean War began when the North Korean Communist army crossed the 38th parallel and invaded non-Communist South Korea. As Kim II-sung's North Korean army, armed with Soviet tanks, quickly overran South Korea. The United States got involved by coming to SK's aid.
World War II divided Korea into a Communist, northern half and an American-occupied southern half, divided at the 38th parallel. The Korean War (1950-1953) began when the North Korean Communist army crossed the 38th Parallel and invaded non-Communist South Korea. As Kim Il-sung's North Korean army, armed with Soviet tanks, quickly overran South Korea, the United States came to South Korea's aid. General Douglas MacArthur, who had been overseeing the post-WWII occupation of Japan, commanded the US forces which now began to hold off the North Koreans at Pusan, at the southernmost tip of Korea. Although Korea was not strategically essential to the United States, the political environment at this stage of the Cold War was such that policymakers did not want to appear "soft on Communism." Nominally, the US intervened as part of a "police action" run by a UN (United Nations) international peace- keeping force; in actuality, the UN was simply being manipulated by US and NATO anti-Communist interests.
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