What were at least two causes of the beginning of world war ii (before america became involved)

becasue in the south they disallowed slavery but in the north slavery was illegial this boilled into because mexico wanted slavery

hope this

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.