In a paragraph of 3–5 sentences, describe the causes of the Korean War.

The Korean War was primarily caused by the ideological divide between communism and capitalism. After World War II, Korea was divided into North Korea, under the influence of the Soviet Union and communism, and South Korea, supported by the United States and capitalism. Tensions arose between the two Koreas, which had different political systems and desired reunification under their respective ideologies. The war was further triggered by North Korea's invasion of South Korea in 1950, seeking to reunify the country under communism. This led to the direct military intervention of the United States and other nations in support of South Korea, resulting in a three-year conflict.