Article I, Section 8, Clause 17:
[The Congress shall have Power . . . ] To exercise exclusive Legislation in all Cases whatsoever, over such District (not exceeding ten Miles square) as may, by Cession of particular States, and the Acceptance of Congress, become the Seat of Government of the United States, and to exercise like Authority over all Places purchased by the Consent of the Legislature of the State in which the Same shall be, for the Erection of Forts, Magazines, Arsenals, dock-Yards, and other needful Buildings;–And . . .
The Convention was moved to provide for the creation of a site in which to locate the Capital of the Nation, completely removed from the control of any state, because of the humiliation suffered by the Continental Congress on June 21, 1783. Some eighty soldiers, unpaid and weary, marched on the Congress sitting in Philadelphia, physically threatened and verbally abused the members, and caused the Congress to flee the City when neither municipal nor state authorities would take action to protect the members.1 Thus, Madison noted that
[t]he indispensable necessity of complete authority at the seat of government, carries its own evidence with it. . . . Without it, not only the public authority might be insulted and its proceedings interrupted with impunity, but a dependence of the members of the general government on the State comprehending the seat of government, for protection in the exercise of their duty, might bring on the national council an imputation of awe or influence, equally dishonorable to the government and dissatisfactory to the other members of the confederacy.2
The actual site was selected by compromise, Northerners accepting the Southern-favored site on the Potomac in return for Southern support for a Northern aspiration, assumption of Revolutionary War debts by the National Government.3 Maryland and Virginia both authorized the cession of territory4 and Congress accepted.5 Congress divided the District into two counties, Washington and Alexandria, and provided that the local laws of the two states should continue in effect.6 It also established a circuit court and provided for the appointment of judicial and law enforcement officials.7