the US wanted the UN to condemn the action of N. Korea, but they had to vote.
the UN did not allow communist china into the UN in 1949, the USSR to protest walked out of the UN, which mean there were no communist countries in the UN.
The US influenced the UN to agree to help S. Korea by being the largest contributor to the UN's budget.
The UN agreed to us force against north korea
After the vote, the North is pushed back to the border at china, china joined north korea and pushed the UN troops back past the 38th parallel.
The leader in charge of all the troops General Mac Arthur wanted to invade china with nuclear weapons, but president truman disagreed and removed him from his position.