Article II, Section 2, Clause 2:

He shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur; and he shall nominate, and by and with the Advice and Consent of the Senate, shall appoint Ambassadors, other public Ministers and Consuls, Judges of the supreme Court, and all other Officers of the United States, whose Appointments are not herein otherwise provided for, and which shall be established by Law: but the Congress may by Law vest the Appointment of such inferior Officers, as they think proper, in the President alone, in the Courts of Law, or in the Heads of Departments.

While treaties may preempt contradictory state law and supplant earlier-in-time federal legislation, the treaty power is not so broad as to override the Constitution.1 The Supreme Court stated in dicta in several cases that treaties may not alter the Constitution or authorize acts that the Constitution expressly prohibits.2 Although the Court has never invalidated a treaty itself on constitutional grounds,3 it has held that courts may not give treaties domestic effect in a way that interferes with individual rights guaranteed in the Constitution.4 In Boos v. Berry, the Supreme Court held that a treaty-based obligation to protect foreign embassies did not authorize Congress to enact legislation that infringed on individuals’ First Amendment right to freedom of speech.5 Similarly, in Reid v. Covert, a plurality of the Court determined that the United States could not rely on international agreements as authority to conduct criminal proceedings that did not comply with the grand-jury and jury-trial guarantees in the Fifth and Sixth Amendments.6 The Supreme Court has since cited the Reid plurality opinion and described its conclusions related to the constitutional constraints on the treaty power as “well established.” 7

Footnotes

1

In Missouri v. Holland, the Supreme Court noted that, whereas the Supremacy Clause gives acts of Congress the status of supreme law of the land only when “made in pursuance” of the Constitution, treaties are deemed supreme law of the land when made “under the authority of the United States.” See 252 U.S. 416, 432 (1920) (discussing U.S. Const. art VI, cl. 2). Holland described it as “an open question” whether the “authority” underlying the treaty power could extend beyond what the Constitution permits. Id. But the Court clarified in subsequent decisions that the treaty power is subject to certain constitutional restraints, and the variation in language in the Supremacy Clause was intended to ensure that treaties made under the Articles of Confederation would remain in effect under the Constitution. See Reid v. Covert, 354 U.S. 1, 16–17 (1957) (plurality opinion).

2

See Doe v. Braden, 57 U.S. (16 How.) 635, 657 (1853) ( “The treaty is . . . a law made by the proper authority, and the courts of justice have no right to annul or disregard any of its provisions, unless they violate the Constitution of the United States.” ); The Cherokee Tobacco, 78 U.S. (11 Wall.) 616, 620 (1870) ( “It need hardly be said that a treaty cannot change the Constitution or be held valid if it be in violation of that instrument.” ); De Geofroy v. Riggs, 133 U.S. 258, 267 (1890) ( “It would not be contended that [the treaty power] extends so far as to authorize what the constitution forbids.” ); Asakura v. City of Seattle, 265 U.S. 332, 341 (1924) ( “The treaty-making power of the United States . . . does not extend ‘so far as to authorize what the Constitution forbids.’” ) (quoting De Geofroy, 133 U.S. at 267). See also Reid, 354 U.S. at 16 ( “This Court has regularly and uniformly recognized the supremacy of the Constitution over a treaty.” ).

3

See Louis Henkin, Foreign Affairs and the U.S. Constitution 185 (2d ed. 1996); Restatement (Fourth) of Foreign Relations § 307 cmt. a (2018).

4

See Boos v. Barry, 485 U.S. 312, 324 (1988) ( “It is well established that ‘no agreement with a foreign nation can confer power on the Congress, or on any other branch of Government, which is free from the restraints of the Constitution.’” ) (quoting Reid, 354 U.S. at 16 (plurality opinion)). See also Am. Ins. Ass’n v. Garamendi, 539 U.S. 396, 416–17 & n.9 (2003) (stating that the power of a treaty to preempt state law is “[s]ubject . . . to the Constitution’s guarantees of individual rights” ).

5

See Boos, 484 U.S. at 324, 334. Although the Supreme Court has not addressed the issue, several lower courts and commentators have concluded that the United States cannot exercise powers that the Constitution assigns exclusively to Congress, such as the appropriations of funds, through a treaty. See ArtII.S2.C2.1.4 Self-Executing and Non-Self-Executing Treaties.

6

The plurality in Reid rejected the argument that an executive agreement between the United States and Great Britain and the North American Treaty Organization Status of Forces Agreement permitted military courts to try the dependents of U.S. military personnel living at overseas posts when the criminal process did not comport with constitutional guarantees of the Fifth and Sixth Amendments. See Reid, 354 U.S. at 15–19 & n.29. See also Amdt5.2.1 Historical Background on Grand Jury Clause and Amdt6.4.2 Historical Background on Right to Trial by Jury (discussing the constitutional guarantees of a grand jury and trial by jury). While only four Justices joined the Reid plurality opinion, none of the separately concurring or dissenting Justices questioned the plurality’s analysis of the treaty power. See 354 U.S. at 41–64 (1957) (Frankfurter, J., concurring in the judgment); Id. at 65–78 (Harlan, J., concurring in the judgment); Id. at 78–90 (Clark, J., dissenting joined by Burton, J.).

7

Boos, 484 U.S. at 324. See also Garamendi, 539 U.S. at 417 n.9 (citing plurality opinion in Reid).