Constitution & Western Territories
The Northwest Ordinance was passed on July 13, 1787. The Constitution of the United States was finalized on September 17, 1787 and ratified by the required nine of thirteen States by June 21, 1788. The new government was not inaugurated until March 4, 1789.
The defect of the Articles of Confederation concerning the capacity to hold title in the soil and exercise authority over the Northwestern Territories and future cessions of "western wastelands" by the original States was cured by Article 3, Section 2 of the Constitution of the United States, ("Property Clause"). [This should be distinguished from the provisions of Article I, Section 8, Clause 17 which apply only to Washington, D.C. and isolated federal "enclaves" established within the boundaries of the States for limited and specific, legitimate governmental purposes.]
"The Congress shall have power to dispose of and make all needful rules and regulations respecting the territory or other property belonging to the United States; and nothing in this Constitution shall be so construed as to prejudice any claims of the United States, or of any particular state."
The "Property Clause" applied only to the territories to which title was ceded in common to the confederated States or anticipated to be ceded to the new United States by the original States out of the "western wastelands" recognized under the Treaty of Paris. It did not apply to "federal enclaves" established within a State or to territory subsequently nationally "acquired" through international treaty, (such as Louisiana and Florida.)
The authority to acquire and govern new territories was based entirely upon the "treaty-making power" and the power to admit new states "into this Union." The law of this "acquired territory" was initially determined by the rule of the Law of Nations and provisions of the ceding treaty. Congress was limited in its capacity to establish government for these "acquired territories" by the limitations of power and the security of individual rights as set forth under the Constitution. Until the new territories could be admitted on an "equal footing" with the original States, Congress served in the capacity of trustee for the people of the nation and the future States.
----> To Exclusive Federal Jurisdiction