the United States. Their will respecting it, manifested
in the Constitution, can be subject to no restriction. The purposes
and objects of the clause were the enactment of laws concerning the
disposal of the public lands, and the temporary government of the
settlers thereon until new States should be formed. It will not be
questioned that, when the Constitution of the United States was framed
and adopted, the allowance and the prohibition of negro slavery were
recognised subjects of municipal legislation; every State had in some
measure acted thereon; and the only legislative act concerning the
territory--the ordinance of 1787, which had then so recently been
passed--contained a prohibition of slavery. The purpose and object of
the clause being to enable Congress to provide a body of municipal law
for the government of the settlers, the allowance or the prohibition
of slavery comes within the known and recognised scope of that purpose
and object.

There is nothing in the context which qualifies the grant of power.
The regulations must be "respecting the territory." An enactment that
slavery may or may not exist there, is a regulation respecting the
territory. Regulations must be needful; but it is necessarily left to
the legislative discretion to determine whether a law be needful. No
other clause of the Constitution has been referred to at the bar, or
has been seen by me, which imposes any restriction or makes any
exception concerning the power of Congress to allow or prohibit
slavery in the territory belonging to the United States.

A practical construction, nearly contemporaneous with the adoption of
the Constitution, and continued by repeated instances through a long
series of years, may always influence, and in doubtful cases should
determine, the judicial mind, on a question of the interpretation of
the Constitution. (Stuart _v._ Laird, 1 Cranch, 269; Martin _v._
Hunter, 1 Wheat., 304; Cohens _v._ Virginia, 6 Wheat., 264; Prigg _v._
Pennsylvania, 16 Pet., 621; Cooley _v._ Port Wardens, 12 How., 315.)

In this view, I proceed briefly to examine the practical construction
placed on the clause now in question, so far as it respects the
inclusion therein of power to permit or prohibit slavery in the
Territories.

It has already been stated, that after the Government of the United
States was organized under the Constitution, the temporary Government
of the Territory northwest of the river Ohio could no longer exis