Why did the United States enter the Korean War?

The reason the United States entered the Korean War centers on the goal to stop the spread of Communism, reflecting the broader context of the Cold War. During this period, the U.S. was deeply concerned about the domino effect that the spread of Communism could have in various regions, particularly in Asia. The invasion of South Korea by North Korea in June 1950 was viewed as a direct challenge to the Western nations and a potential threat to the stability of the region.

By intervening, the United States aimed to halt North Korea's aggressive expansion and prevent the establishment of a Communist regime in all of Korea, which could inspire similar movements in other countries. The American military response was part of a larger strategy of containment, which sought to limit the influence of the Soviet Union and Communist ideologies worldwide. Thus, this action not only supported South Korea but also aligned with the fundamental U.S. policy of preventing the advance of Communism in any form.