The Great Barrier
If Religion be exempt from the authority of the Society at large, still less can it be subject to that of the Legislative Body. The latter are but the creatures and vicegerents of the former. Their jurisdiction is both derivative and limited: it is limited with regard to the co-ordinate departments, more necessarily is it
limited with regard to the constituents. The preservation of a free Government requires not merely, that the metes and bounds which separate each department of power be invariably maintained; but more especially that neither of them be suffered to overlap the great Barrier which defends the rights of the people. The Rulers who are guilty of such an encroachment exceed the commission from which they derive their authority, and are Tyrants. The People who submit to it are governed by laws made neither by themselves nor by an authority derived from them, and are slaves.
—James Madison, from “Memorial and Remonstrance Against Religious Assessments,” written to the General Assembly of the Commonwealth of Virginia, 1785.