The Federalist Papers by Alexander Hamilton, John Jay, and James Madison

5. "To dispose of and make all needful rules and regulations respecting

the territory or other property belonging to the United States," with a proviso, that "nothing in the Constitution shall be so construed as to prejudice any claims of the United States, or of any particular State." This is a power of very great importance, and required by considerations similar to those which show the propriety of the former. The proviso annexed is proper in itself, and was probably rendered absolutely necessary by jealousies and questions concerning the Western territory sufficiently known to the public.