The U.S Policy of Containment was a policy created to prevent the spread of communism.
This was used during the Korean War because, North Korea had invaded the South in attempt of unifying both countries in means of communism. So to prevent this from happening, the U.S and other nations joined in on the war to give support. NATO ( the North Atlantic Treaty Organization), also put in effort and helped South Korea. In return, South Korea wholeheartedly accepted their support as well.
As the U.S and other nations pitched in to give a helping hand to South Korea, things have gone the way it was planned and caused North Korea to stop their scheme in domination over all of Korea.
This was used during the Korean War because, North Korea had invaded the South in attempt of unifying both countries in means of communism. So to prevent this from happening, the U.S and other nations joined in on the war to give support. NATO ( the North Atlantic Treaty Organization), also put in effort and helped South Korea. In return, South Korea wholeheartedly accepted their support as well.
As the U.S and other nations pitched in to give a helping hand to South Korea, things have gone the way it was planned and caused North Korea to stop their scheme in domination over all of Korea.