16. To provide for organizing arming, and disciplining the mili-
tia, and for governing such part of them as may be employed in the
service of the United States; reserving to the states respectively the
appointment of the officers, and the authority of training the militia
according to the discipline prescribed by Congress.
17. To exercise exclusive legislation, in all cases whatsoever,
over such district (not exceeding ten miles square) as may, by ces-
sion of particular states, and the acceptance of Congress, become the
seat of the 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 sorts, ma-
gazines, arsenals, dock yards, and other needful buildings; and
18. To make all laws, which shall be necessary and proper for
carrying into execution the foregoing powers, and all other powers
vested by this Constitution in the government of the United States,
or in any department or officer thereof.