United States v. Alvarez-Machain

The primary government argument before the Court was not that the treaty authorized abduction of Mexican citizens by U.S. authorities, but that it did not prohibit such abductions. Machain argued the treaty did not expressly recognize the Ker-Frisbie doctrine, and in fact, Article 9 of the treaty allowed for Mexico to deny U.S. extradition requests. The Court, therefore, deliberated which applied, the Ker-Frisbie doctrine recognizing jurisdiction over abducted defendants or the Rauscher (1886) decision denying jurisdiction if a treaty was violated.

Chief Justice Rehnquist delivered the opinion of the majority in a 6-3 vote. A key finding by Rehnquist was that Mexico had been made aware of the Ker-Frisbie doctrine as early as 1906. As to whether Mexico accepted or recognized the legal principle was not an issue. Rehnquist wrote, therefore, the treaty merely established one option available to obtain a suspect in addition to forcible abduction. Rehnquist concluded the abduction may have been "shocking" and may have violated "general international law principles." However, those matters were for the executive branch to address and not the subject of the Court. The Court was only to determine the relationship of the abduction to the treaty. In that regard, the abduction was found not in violation of the treaty and the Ker-Frisbie doctrine fully applied. The forced abduction did not negate a fair trial under U.S. court jurisdiction. The court of appeals decision was reversed and the case remanded back to the district court for trial.