From Volume 79, Number 6 (September 2006)
The treaty lives a double life. By day, it is a creature of international law, which sets forth extensive substantive and procedural rules by which the treaty must operate. When these rules prove susceptible to dispute – as is the case with treaty reservations, for example – international lawyers vigorously debate both how to clarify the rules and who has the authority to do so. By night, however, the treaty leads a more domestic life. In its domestic incarnation, the treaty is a creature of national law, deriving its force from the constitutional order of the nation state that concluded it. Within the United States, therefore, the Constitution governs. Just as we look to international law to discern treaty rules on the international plane, so too must we look to the Constitution for substantive or procedural rules by which the treaty functions within the U.S. legal system.
In contrast to international law’s more comprehensive framework, the Constitution contains only three express commands with respect to treaties: (1) the federal government makes treaties; (2) the judiciary can hear cases concerning treaties; and (3) treaties trump state law. First, in vesting executive power in the president, Article II assigns him the “Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two-thirds of the Senators present concur.” At the same time, Article I denies states the right to “enter into any Treaty, Alliance, or Confederation.” Second, Article III extends the judicial power “to all Cases, in Law and Equity, arising under… Treaties made, or which shall be made, under” the authority of the United States. Third, in Article VI the Constitution mandates that, like federal law, “all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges of every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding.”