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. The former will be exercised principally on external objects, as war, peace, negotiation and foreign commerce. ... The powers reserved to the several States will extend to all the objects which in the ordinary course of affairs, concern the lives and liberties, and properties of the people, and the internal order, improvement and prosperity of the State.
James Madison
10th-amendment, government