The United States was correct in going to war against North Korea in support of their territory of South Korea.
After the eve of WW2, and the fall of the expansive Japanese empire, many Japanese territories were confiscated from their former controllers, and made into new nations. Two of these newly independent countries were North and South Korea. The two independent nations had formerly been a single nation prior to Japanese annexation, at which point it remained a single nation, but fell under harsh Japanese rule. However, when the war ended the nation, upon gaining its freedom from Japan, was immediately split between North and South, the former occupied by the Soviet Union, and the latter occupied by the United States. Much like in the case of Germany’s split occupation, what was initially meant to be only temporary, eventually became long term. The Soviets established a Communist regime in North Korea, while the United States supported the fledgling capitalism in the South economically and militarily. For a time this went on in relative, if not tense, peace. Suddenly, on June 25, 1950, this tentative peace was broken as North Korea’s armed forces began to invade the south, and made their way to the nation’s capital.
With support from communist powerhouses China and the USSR, North Korea would have quickly extinguished its southern adversaries, had the United States not stepped in. South Korea was and still is a sovereign nation, and did not, and still does not, desire to become communist, when the American Forces interceded in the conflict they were merely defending an ally in need. Had the war been strictly between North and South Korea, United States intercession may not have been necessary, for North Korea only had roughly 233,000 troops during the onset. However, China would eventually contribute two million soldiers to the North Korean cause, and The Soviet Union Union, although they denied involvement, would contribute their technology, their tactics, and even their training for a North Korean, and Chinese air force. This combined threat demanded America assist South Korea, which would be inevitably crushed under the combined force of the assault, without aid. In fact, on the North Korean army’s initial strike South Korean forces were pushed back to the southernmost tip of the peninsula; Korea was almost entirely united once more under a communist regime. Although South Korea desired unity, understandably they desired a united nation in which they had the economy that they chose, not an economic system that was forced upon them. The overwhelming threat of the communist conquest of their close ally, South Korea, motivated American assistance in the form 5,720,000 troops, troops that would protect the South Koreans right to the economy that they desired.