To stop the communist forces from reuniting Korea under a communist government
It was called a "police action"
South Korea.
Stop communist aggression.
Korea had been taken over by the Japanese prior to the war. Thus, one goal of the Allied Pacific war was to liberate Korea from Japanese control. Korea was not an enemy of the Americans; it was more of the damsel in distress.
Easily, but such an action would trigger an attack by China on the US in retaliation and we would have a full blown nuclear war.
Korea
To stop South Korea from becoming communist.
South Korea
South Korea
North Korea has issues with the US. But the US does not hate Korea. The US has a strong and very old alliance with China that makes then stronger than Korea.
Russia walked out of the UN so the US was able to get UN to agree to send troops to defend South Korea. The active fighting stopped after 2 years, but no peace treaty was ever signed.
The invasion of the Republic of Korea by the Democratic People's Republic of Korea (Noth by South).