Ruhrgas AG v. Marathon Oil Co.

Marathon entities (plaintiffs) sued Ruhrgas (defendant) in Texas state court over a gas-production dispute, and Ruhrgas removed the case to federal court, where it moved to dismiss for lack of personal jurisdiction while Marathon separately moved to remand for lack of subject-matter jurisdiction (disputing complete diversity). The district court dismissed for lack of personal jurisdiction without addressing subject-matter jurisdiction; a Fifth Circuit panel held subject-matter jurisdiction had to be decided first, but the en banc Fifth Circuit agreed that removed cases require deciding subject-matter jurisdiction before personal jurisdiction, and the Supreme Court granted certiorari to resolve a circuit split.