Antoine v. Washington
In Antoine v. Washington, 420 U.S. 194 (1975), the Court had to interpret a statute "ratifying" an agreement between the Colville Confederated Tribes and the United States. Id. at 198 (quoting 34 Stat. 1015, 1050-1051 (1907)).
The question before the Court was whether a provision in the ratified agreement preempted a Washington state law.
The Washington Supreme Court had interpreted the statute as not giving the agreement the force of law because the agreement was not a treaty.
The Supreme Court disagreed, holding that,"once ratified by Act of Congress, the provisions of the agreements become law, and like treaties, the supreme law of the land." Id. at 204.