the
duty, to determine the matter according to its own ideas of what is
expedient, that Madison has been most completely vindicated by
developments. This is seen in the answer which the Court has returned to
the question, as to what happens when a treaty provision and an act of
Congress conflict. The answer is, that neither has any intrinsic
superiority over the other and that therefore the one of later date will
prevail _leges posteriores priores contrarias abrogant_. In short, the
treaty commitments of the United States in no wise diminish Congress's
constitutional powers. To be sure, legislative repeal of a treaty as law
of the land may amount to a violation of it as an international contract
in the judgment of the other party to it. In such case, as the Court has
said, "Its infraction becomes the subject of international negotiations
and reclamations, so far as the injured party chooses to seek redress,
which may in the end be enforced by actual war. It is obvious that with
all this the judicial courts have nothing to do and can give no
redress."[172]

TREATIES _Versus_ PRIOR ACTS OF CONGRESS

The cases are numerous in which the Court has enforced statutory
provisions which were recognized by it as superseding prior treaty
engagements. How as to the converse situation? Two early cases in which
Chief Justice Marshall spoke for the Court, stand for the proposition
that treaties, so far as self-executing, repeal earlier conflicting acts
of Congress. In the case of the "_Peggy_,"[173] certain statutory
provisions dealing with the trial of prize cases were held to have been
modified by a subsequent treaty with France; and in Foster _v._.
Neilson,[174] while holding--mistakenly as he later admitted[175]--that
the treaty of January 24, 1818 with Spain was not self-executing with
respect to certain land grants, he went on to say that if it had been it
would have repealed acts of Congress repugnant to it. With one
exception, however, judicial dicta which reiterate this idea are obiter,
and are disparaged by Willoughby, as follows: "In fact, however, there
have been few (the writer is not certain that there have been any)
instances in which a treaty inconsistent with a prior act of Congress
has been given full force and effect as law in this country without the
assent of Congress. There may indeed have been cases in which, by
treaty, certain action has been taken without reference to existing
Federal laws, as, for example