The clause deals with powers that are ambiguous and misinterpreted.
The "necessary and proper" clause is included in Article I, Section 8, of the United States Constitution. After enumerating a number of the powers of Congress, including borrowing money, coining money, regulating commerce, etc, Section 8 of Article I closes with by saying Congress shall have power "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." That's a quite broad and sweeping statement. Political leaders have differed in how they would interpret and apply that sort of authority.
