Right here:
"To make 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."
Every law requires someone to enforce that law. What part of this is confusing you?
Right.
Libertarian by default; I'm not sure I can run my own life, but I'm damn sure I don't trust anyone else to do it for me.