ations; and if the government should not insure them that, the
promises made to them in its behalf would not be performed.

I contend, therefore, in conclusion on this point, that the power of
Congress over these high branches of commercial regulation is shown to
be exclusive, by considering what was wished and intended to be done,
when the convention for forming the Constitution was called; by what was
understood, in the State conventions, to have been accomplished by the
instrument; by the prohibitions on the States, and the express exception
relative to inspection laws; by the nature of the power itself; by the
terms used, as connected with the nature of the power; by the subsequent
understanding and practice, both of Congress and the States; by the
grant of exclusive admiralty jurisdiction to the federal government; by
the manifest danger of the opposite doctrine, and the ruinous
consequences to which it directly leads.

Little is now required to be said, to prove that this exclusive grant is
a law regulating commerce; although, in some of the discussions
elsewhere, it has been called a law of police. If it be not a regulation
of commerce, then it follows, against the constant admission on the
other side, that Congress, even by an express act, cannot annul or
control it. For if it be not a regulation of commerce, Congress has no
concern with it. But the granting of monopolies of this kind is always
referred to the power over commerce. It was as arbiter of commerce that
the king formerly granted such monopolies.[4] This is a law regulating
commerce, inasmuch as it imposes new conditions and terms on the
coasting trade, on foreign trade generally, and on foreign trade as
regulated by treaties; and inasmuch as it interferes with the free
navigation of navigable waters.

If, then, the power of commercial regulation possessed by Congress be,
in regard to the great branches of it, exclusive; and if this grant of
New York be a commercial regulation, affecting commerce in respect to
these great branches, then the grant is void, whether any case of actual
collision has happened or not.

But I contend, in the second place, that whether the grant were to be
regarded as wholly void or not, it must, at least, be inoperative, when
the rights claimed under it come in collision with other rights, enjoyed
and secured under the laws of the United States; and such collision, I
maintain, clearly exists in this case. It will not be d