When North Korea invaded South Korea in 1950, the USA and most nations in the United Nations saw this invasion as a threat to peace and the possible take over of South Korea by North Korea. In order to keep South Korea a free an independent nation, the USA and the United Nations formed a coalition of armed forces to counter act the North Korean invasion.
South Korea, US vs North Korea, USSR, China
Vietnam and Korea .
the United Nations forces, which protected South Korea from an invasion by North Korea.
The US and North Korea.
The US reinforced the South Koreans and fought northward into North Korea.
Korea is a peninsula. US/Allied Troops landed in South Korea, and fought their way north from there.
To stop the spread of communism, since North (Communist) Korea was attacking South (Democratic) Korea.
Nothing, they werent involved. It was between The Soviet Union and the US
North Korea's becoming nuclear power and extending continuous threat to South Korea which is an ally of USA, led the later to intervene and get involved.
The USA wanted to stop the spread of communism through the world
The Korean War was actually a Police Action that involved the United Nations and North Korea. North Korea was Chinese and Russian backed. They invaded South Korea. This argument was the result of the Cold War and the bad feelings from that. Both Countries are really still at war.
The war in Vietnam was similar to the US Civil War because the war involved North Korea versus South Korea.