duties, and to make all laws
necessary and proper for carrying those powers into execution. That the
act now in question is within the legislative power of Congress, unless
that power is controlled by the treaty, is not doubted. It must be
admitted, also, that in general, power to legislate on a particular
subject, includes power to modify and repeal existing laws on that
subject, and either substitute new laws in their place, or leave the
subject without regulation, in those particulars to which the repealed
laws applied. There is therefore nothing in the mere fact that a treaty
is a law, which would prevent Congress from repealing it. Unless it is
for some reason distinguishable from other laws, the rule which it gives
may be displaced by the legislative power, at its pleasure. * * * I
think it is impossible to maintain that, under our Constitution, the
President and Senate exclusively, possess the power to modify or repeal
a law found in a treaty. If this were so, inasmuch as they can change or
abrogate one treaty, only by making another inconsistent with the first,
the government of the United States could not act at all, to that
effect, without the consent of some foreign government; for no new
treaty, affecting, in any manner, one already in existence, can be made
without the concurrence of two parties, one of whom must be a foreign
sovereign. That the Constitution was designed to place our country in
this helpless condition, is a supposition wholly inadmissible. It is not
only inconsistent with the necessities of a nation, but negatived by the
express words of the Constitution. * * *" _See also_ The Cherokee
Tobacco, 11 Wall. 616 (1871); United States _v._ Forty-Three Gallons of
Whiskey, 108 U.S. 491, 496 (1883); Botiller _v._ Dominguez, 130 U.S. 238
(1889); Chae Chan Ping _v._ United States, 130 U.S. 581, 600 (1889);
Whitney _v._ Robertson, 124 U.S. 190, 194 (1888); Fong Yue Ting _v._
United States, 149 U.S. 688, 721 (1893); etc. "Congress by legislation,
and so far as the people and authorities of the United States are
concerned, could abrogate a treaty made between this country and another
country which had been negotiated by the President and approved by the
Senate." La Abra Silver Mining Co. _v._ United States, 175 U.S. 423, 460
(1899). _Cf._ Reichert _v._ Felps, 6 Wall. 160, 165-166 (1868), where it
is stated obiter that "Congress is bound to regard the public treaties,
and it had no power * * * to nullify [I