What was the reason for u. S. Involvement in the korean war?

To stop the spread of communism

Explanation:

The US help South Korea in the war because the north was trying to convert the south into communism.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

the roman empire began to fall