“The powers delegated by the proposed Constitution to the federal government are few and defined. Those which are to remain in the State governments are numerous and indefinite.” – James Madison, Federalist 45, 1788
“The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.” – Tenth Amendment, 1791
“I consider the foundation of the Constitution as laid on this ground that ‘all powers not delegated to the United States, by the Constitution, nor prohibited by it to the states, are reserved to the states or to the people.’ To take a single step beyond the boundaries thus specially drawn around the powers of Congress, is to take possession of a boundless field of power, not longer susceptible of any definition.” – Thomas Jefferson, Opinion on the Constitutionality of a National Bank, 1791