The primary role of the federal government is the defense of our nation. How do I know that? Because I have read the US Constitution. Secondary roles are found in the enumerated powers. How do I know that? Because I've read the US Consitution. The US Constitution specifically spells it out and all other power is delegated to the states and the people.
The Bill of Rights tells us many things about what the US government cannot do. Same with the body of the Constitution. The founders weren't concenred with having, nor wanting, a powerful central government. It specifically says "limited" federal government. Now we see what we see becuase We, the People have let these corrupt pick pockets we call politicians try to make the US Constitution irrelevant. Folks that comes at the expense of the citzens and our continued freedoms.