James Madison in “Federalist” 45:

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, liberties, and properties of the people, and the internal order, improvement, and prosperity of the State.

So how did we go from 2 to 15 seats in POTUS’ Cabinet?

The President’s Cabinet
Department of Agriculture
Established: 1862

Department of Commerce
Established: 1903

Department of Defense
Established:1947

Department of Education
Established: 1979

Department of Energy
Established: Aug. 1977

Department of Health and Human Services
Established: 1953

Department of Homeland Security
Established: 2003

Department of Housing and Urban Development
Established: 1965

Department of the Interior
Established: 1849

Department of Justice
Established: 1870

Department of Labor
Established: 1913

Department of State
Established: 1789

Department of Transportation
Established: 1966