Why did U.S. go to war in both Korea and Vietnam during the cold war?

Answer 1

During the Cold War, it was the belief of the US that the Soviet Union was engaged in a program of global conquest, by which it would take over countries one after another, until eventually the US would remain as the single independent nation left in the world, at which point it would be subject to crushing economic blockade by the otherwise all-encompassing Soviet world, and then it too would eventually be consumed by the Soviet Dictatorship, which would enslave the entire human race and bring an end to human liberty forever. In order to avoid this unpleasant fate, it was the policy of the US to oppose all communist revolutions or take-overs, wherever they may occur. When communist North Korea invaded non-communist South Korea, the US therefore had to support the south, and when communist North Vietnam invaded non-communist South Vietnam, again the US had to support the south. Although in hindsight we can see that the threat of a communist global take-over was overstated, it is still true that to this day, in the year 2012 as I type, North Korea is ruled by a psychotic Stalinist dictatorship, and South Korea is a prosperous and democratic country which produces amazing YouTube videos, so the US efforts in Korea were not in vain. However, US efforts in Vietnam did prove to be futile. These things can be very hard to predict.

Answer 2

The United States intervened in the Korean War (1950-1953) to prevent the spread of communism on the Korean Peninsula. It was an effort to defend South Korea against the invasion from North Korea, which was supported by the Soviet Union and China. In Vietnam, the U.S. became involved to prevent the spread of communism in Southeast Asia and support the South Vietnamese government against the communist North. The U.S. feared the "domino theory" where the fall of one country to communism would lead to the fall of others in the region.