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.

The Constitution provides that both federal statutes and treaties are part of the supreme law of the land, but it does not define the relationship between federal legislation and treaties.1 As a result, disputes have arisen over which law governs when there are differences between a self-executing treaty and a federal statute. The Supreme Court has resolved this issue through what has become known as the “last-in-time” or “later-in-time” rule: when there is a conflict between a self-executing treaty and a federal statute, U.S. courts must apply whichever of the two reflects the “latest expression of the sovereign will” of the United States.2

The Supreme Court has frequently applied the last-in-time rule to give effect to a statute that conflicts with an earlier ratified treaty.3 Although the situation has arisen less often, the Supreme Court has also held that a treaty can override an earlier-in-time federal statute.4 The last-in-time rule, however, only applies when the treaty at issue is self-executing.5 Because a non-self-executing treaty is not judicially enforceable,6 courts will apply a federal statute over a non-self-executing treaty regardless of the timing of the statute’s enactment.7

Footnotes

1

U.S. Const. art. VI, cl. 2.

2

Whitney v. Robertson, 124 U.S. 190, 195 (1888). See also Chinese Exclusion Case (Ping v. United States), 130 U.S. 581, 600 (1889) ( “[T]he last expression of the sovereign will must control.” ).

3

See, e.g., Breard v. Greene, 523 U.S. 371, 376 (1998) (per curiam on denial of certiorari); Chinese Exclusion Case, 130 U.S. at 600–01; Whitney, 124 U.S. at 194–95; Head Money Cases (Edye v. Robertson), 112 U.S. 580, 596–99 (1884).

4

See Cook v. United States, 288 U.S. 102, 118–19 (1933) (holding that a 1924 treaty between the United States and Great Britain superseded the terms of the Tariff Act of 1922 and limited the authority of the Coast Guard to board a British vessel outside U.S. territorial waters). See also The Cherokee Tobacco, 78 U.S. (11 Wall.) 616, 621 (1870) ( “A treaty may supersede a prior act of Congress, and an act of Congress may supersede a prior treaty.” ) (footnote omitted).

5

Whitney, 124 U.S. at 194 ( “[I]f the [treaty and statute] are inconsistent, the one last in date will control the other: provided, always, the stipulation of the treaty on the subject is self-executing.” ). See also Medellín v. Texas, 552 U.S. 491, 505–06 (2008) ( “Only '[i]f the treaty contains stipulations which are self-executing, that is, require no legislation to make them operative, [will] they have the force and effect of a legislative enactment.’” ) (quoting Whitney, 124 U.S. at 194); Apparatus for Radio Communication on Steam Vessels, 30 Op. Att’y Gen. 84, 86 (1913) ( “[U]nless a treaty is self-executing, it will not necessarily repeal a prior and inconsistent statute on the same subject.” ).

6

See ArtII.S2.C2.1.4 Self-Executing and Non-Self-Executing Treaties.

7

See supra note 5. See also Restatement (Fourth) of Foreign Relations Law § 109 cmt. c (2018); David M. Golove, Treaty-Making and the Nation: The Historical Foundations of the Nationalist Conception of the Treaty Power, 98 Mich. L. Rev. 1075, 1100–04 (2000).