The States are Unavoidably Bound by International Law

JURIST Contributing Editor Jordan Paust of the University of Houston Law Center says that despite recent legislative efforts to prevent the enforcement of international law, state governments are obligated to do so by the US Constitution...

Some states and members of state legislatures have attempted to create legislation that would obviate or restrict the use of international law in their courts. Under the text and structure of the US Constitution and predominant trends in federal and state judicial decisions, this would not be constitutionally permissible.

Under the Supremacy Clause of the constitution, it is unavoidably mandated that, along with the constitution:

"[T]he Laws of the United States ... and all Treaties ... shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any thing in the Constitution or Laws of any State to the Contrary notwithstanding."
The constitution expressly requires that "all" treaties shall have that effect, not merely some of them, the ones that a state might like or those that have already been executed by the president or the US Congress.

With respect to the primacy of treaties, as documented in a previous study of the historic reach of the treaty power:

[T]o decide otherwise would be to attempt to rewrite the text of the Constitution, to ignore overwhelming views of the Founders and Framers concerning the primacy of treaties, and to ignore the constitutional design and predominant trends in judicial decisions.
Moreover, as the study explained, the Tenth Amendment altered state powers and sovereignty, expressly limiting them to (1) those "powers not delegated to the United States by the Constitution," and (2) those powers that are not "prohibited by it to the States." Under Article II, Section 2 of the constitution, the president "shall have Power, by and with the Advice and Consent of the Senate to make Treaties" and under Article III, Section 2, "[t]he judicial Power shall extend to all Cases ... arising under Treaties." Therefore, the treaty power was expressly delegated to the US.

Furthermore, the treaty power was expressly prohibited to the states in Article I, Section 10, which declares that "[n]o State shall enter into any Treaty." Additionally, the text of the constitution clearly and unavoidably mandates that "all" treaties are supreme law of the land binding the states and the state judiciary. For these reasons, the US Supreme Court and other federal court cases have long recognized that there is no competing power of the states. With respect to treaty law, "the Tenth Amendment is no barrier" and "whatever is within ... [the] scope [of the treaty power] is not reserved to the states [and] the Tenth Amendment is not material."

As long ago as 1880, a federal circuit court similarly observed:

There can be no mistaking the significance or effect of these plain, concise, emphatic provisions. The states have surrendered the treaty-making power to the general government, and vested it in the president and senate; and, when duly exercised..., the treaty resulting is the supreme law of the land, to which not only state laws but state constitutions are in express terms subordinated.
The Supreme Court has affirmed that:
"[T]reaties of course 'are as binding within the territorial limits of the States as they are elsewhere throughout the dominion of the United States'" and treaties can reach "matters which in ... [their] silence ... the State may regulate."
With respect to matters that "usually fall within the control of the State," "a treaty may override its power." As early as 1792, a federal circuit court stated that treaties are "obligatory" domestically and "must necessarily control all acts issuing from the inferior authority which might contravene it" (i.e., the state, including unavoidably the state judiciary). As another federal court recognized:
[T]he treaty furnishes the law, and with that treaty no state or municipal corporation thereof can interfere. Admit the wedge of state interference ever so little, and there is nothing to prevent its being driven home and destroying the treaty-making power altogether.
The study of the reach of the treaty power also documented the fact that generations of federal and state judges in at least 45 federal (including mostly Supreme Court decisions) and 45 state court cases have consistently recognized the overriding domestic reach of treaty-based law and law radiating from other international agreements to matters that otherwise might have been the prerogative of the state. These areas include state court criminal jurisdiction and criminal law, state court criminal proceedings, state statutes of limitation, state rules of evidence, other state procedural laws regarding access to courts and remedies, state personal injury laws and workmen's compensation, state family law, title to and use of land and leases, control of water, title to personalty located in the state, control of debts, police power control of local businesses and employment, state power of exclusion and detention of persons and the alleged necessity to seize persons in order to protect state security, contract bidding, state registration of persons for employment, vehicle registration, driver's licenses, state taxes and inheritance.

With respect to the primacy of customary international law as part of the "Laws of the United States," another study documented that such a primacy appeared in overwhelming views of the founders and framers. Additionally, generations of federal and state judges have affirmed that customary international law is the supreme law of the land and that the states are bound thereby under the Supremacy Clause. The second study demonstrates that at least 19 federal (including mostly Supreme Court decisions) and 30 state court cases have already recognized the supremacy of customary international law.

Quite clearly, state legislative attempts to avoid the reach of international law are futile unless the Supremacy Clause of the United States Constitution is amended and the predominant views of the founders and framers are abandoned.

Jordan Paust is the Mike & Teresa Baker Law Center Professor at the University of Houston Law Center and has extensive experience in international law. Paust is one of the most cited law professors in the US and has published over 180 articles, book chapters, papers and essays addressing treaty law, customary international law, and the incorporation of international law into US domestic law.

Suggested citation: Jordan Paust, The States are Unavoidably Bound by International Law, JURIST - Forum, June 8, 2012,

This article was prepared for publication by Caleb Pittman, head of JURIST's academic commentary service. Please direct any questions or comments to him at

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