What was the federalist and who was the publius?

The Federalists were the people who strongly supported the newer Constitution of 1787. They wrote the Federalist Papers, which was 85 ages to because they really wanted the constitution ratified. The Publius was the name given to the pen that wronte the Federalists Papers.

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.