The UN fought in Korea.
to rid North Korean and Chinese force from South Korea
They were afraid that the advancing UN forces would not stop at the border but follow the fleeing North Korean forces into China, thus invading China.
...nothing...
The Korean War was a proxy war between the Chinese and Americans.
The S.Koreans asked for the UN help.
The UN.
UN
The UN (United Nations).
money lol
to clear south Korea from occupation by north Korean and Chinese troops
It was an undeclared war.
The UN wasn't really involved in the Vietnam war. It was more involved in the Korean war which happened a few years earlier. American's fear of commmunism seemed to be cemeted when North Korea attacked South Korea, America then asked the UN intervenean to stop the attack. Eventually they organised a military force to stop the attack.