Trump v. Barbara · ¶439

The question of citizenship came up regularly in cases in which the jurisdiction of a federal court was invoked based on diversity of citizenship, but the issue in those cases was whether one or more of the parties were citizens of a particular State, not whether they were citizens at all. A party wishing to challenge federal jurisdiction had no incentive to argue that an adverse party was an alien because both Article III of the Constitution and §11 of the Judiciary Act of 1789, 1 Stat. 78, conferred jurisdiction over cases between citizens and aliens. Therefore, an adverse party who showed that a supposedly diverse citizen was actually not a citizen at all would have confirmed the jurisdiction he sought to oust.

slip opinion, revised 7/01/26
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