Royal Canin U.S.A. v. Wullschleger

Pet owner Anastasia Wullschleger filed a class action in Missouri state court against Royal Canin USA and Nestlé Purina PetCare, alleging that their prescription requirement for certain pet foods violated state antitrust and consumer protection laws, and also included a federal Sherman Act claim. The defendants removed the case to federal court. After the federal claim was dismissed for failure to state a claim, the district court exercised supplemental jurisdiction and dismissed the state-law claims as well. The Eighth Circuit reversed, holding that once federal claims are dismissed, the district court must remand the state claims to state court. The Supreme Court granted review to resolve a circuit split over the proper application of supplemental jurisdiction under 28 U.S.C. § 1367. On January 15, 2025, the Court reversed the Eighth Circuit, reaffirming that district courts have discretion to retain or remand state-law claims after federal claims are eliminated.

The U.S. Supreme Court reversed the Eighth Circuit, holding that district courts are not automatically required to remand state-law claims after federal claims are dismissed; they retain discretion to exercise supplemental jurisdiction, consistent with Carnegie-Mellon University v. Cohill.

Whether a federal district court, after dismissing all federal claims, is required to remand the remaining state-law claims to state court, or whether it retains discretion under 28 U.S.C. § 1367 to exercise supplemental jurisdiction over those claims.

The ruling clarifies federal removal and remand procedures, preserving district courts' discretionary authority over mixed federal-state cases. It affects litigation strategy for defendants who remove cases to federal court and for plaintiffs seeking to return to state court, particularly in consumer and antitrust class actions.