Takeaway: Class action plaintiffs often endeavor to structure their complaints to avoid federal jurisdiction. To avoid federal diversity jurisdiction, for example, class plaintiffs often will name non-diverse defendants with little to no involvement in the operative events, keeping the case out of federal court unless the rigorous standard of “fraudulent joinder” can be met. The U.S. Supreme Court recently addressed a similar—but relatively uncommon—jurisdictional dispute where a class action had been removed on federal question grounds. In Royal Canin U. S. A., Inc. v. Wullschleger, No. 23-677, 2025 WL 96212 (U.S. Jan. 15, 2025), the Court held that a post-removal amendment eliminating all federal questions from the complaint terminated federal question jurisdiction and thus required the case to be remanded to state court.
The decision in Royal Canin involved extensive jurisdictional wrangling. The putative class plaintiff there sued Royal Canin, a corporation headquartered in the forum state (Missouri), asserting various state law claims that relied in part on alleged violations of the Federal Food, Drug, and Cosmetic Act (FDCA). 2025 WL 96212, at *4. Royal Canin removed on federal question grounds and ultimately persuaded the Eighth Circuit that federal question jurisdiction existed because “the meaning of the referenced FDCA provisions was thoroughly embedded in, and integral to the success of,” the class plaintiff’s state law claims. Id. at *4 n.1 (citing Wullschleger v. Royal Canin U. S. A., Inc., 953 F.3d 519, 522 (8th Cir. 2020)).
But because the class plaintiff did not want “the case to be resolved” in federal court, however, she “amended her complaint to delete its every mention of the FDCA, leaving her state claims to stand on their own.” 2025 WL 96212, at *4. Despite the amendment, the district court denied the plaintiff’s renewed motion to remand and granted Royal Canin’s motion to dismiss for failure to state a claim on which relief can be granted. Wullschleger v. Royal Canin USA, Inc., No. 19-00235-CV-W-GAF, 2022 WL 1164662 (W.D. Mo. Mar. 22, 2022). This time around, however, the Eighth Circuit reversed, ruling the amended complaint superseded the original complaint and eliminated federal question jurisdiction (as well as any possibility of supplemental jurisdiction). Wullschleger v. Royal Canin U.S.A., Inc., 75 F.4th 918 (8th Cir. 2023).
The Supreme Court granted certiorari to resolve a split among the Circuits as to whether a post-removal amendment can eliminate federal question jurisdiction predicated on the original complaint. 2025 WL 96212, at *5. Writing for a unanimous Court, Justice Kagan affirmed the Eighth Circuit’s holding that the post-removal amendment eliminated federal question jurisdiction. Id.
The Supreme Court began by surveying federal courts’ jurisdiction over federal question claims and “supplemental jurisdiction” over related state-law claims. Id. at *5-6. Royal Canin pointed to the broad language of the supplemental jurisdiction statute (28 U.S.C. § 1367(a)) extending federal jurisdiction to “‘all other claims’ within the case or controversy, unless Congress ‘expressly provided otherwise.’” Id. at *6. According to Royal Canin, since “Congress did not expressly provide that an amendment deleting federal claims eliminate supplemental jurisdiction,” then a post-removal amendment “cannot divest the court of supplemental jurisdiction.” Id.
The Court rejected this argument because no language in Section 1367(a) “distinguishes between cases removed to federal court and cases originally filed there.” Id. And in federal question cases originally filed in federal court, the Supreme Court had held that an amendment withdrawing the federal claims “divests the federal court of adjudicatory power.” Id. (citing Rockwell Int’l Corp. v. United States, 549 U.S. 457, 472-74 (2007)). Thus, whenever a plaintiff in a federal question case eliminates the federal claims at the outset of the litigation, “there is no discretion to decline supplemental jurisdiction” because the federal basis for supplemental jurisdiction has been eliminated. Id.
The Royal Canin court distinguished cases removed on federal question grounds from cases removed based on federal diversity jurisdiction, where federal courts evaluate the parties’ citizenship “at the time a suit is brought, and never again later.” Id. at *7 & n.5. That “so-called time-of-filing rule” applied only to diversity jurisdiction and “concerns only the actual ‘state of things’ relevant to jurisdiction—meaning, the facts on the ground, rather than (as addressed here), the claims that the plaintiff includes in a complaint.” Id. (discussing Rockwell, 549 U.S. at 473). But while an existing party’s change in citizenship does not impact diversity jurisdiction, “amending a complaint to join a non-diverse party destroys diversity jurisdiction.” Id. at *8. This latter rule also determined “federal jurisdiction—or its absence” from the amended complaint. Id.
The Court similarly distinguished cases holding an amendment reducing the alleged amount-in-controversy “will usually not destroy diversity jurisdiction.” Id. at *8 n.8. As with the “time-of-filing rule” applicable to the original parties’ citizenship, the “value of a suit” constitutes a “fact on the ground” rather than the “plaintiff’s selection of claims and parties.” Id. Measuring the amount-in-controversy only at the outset of the case, moreover, avoids “‘constant litigation’ over the matter” that “‘would be wasteful.’” Id.
The Royal Canin court concluded its analysis by confirming that the plaintiff’s original complaint properly had been removed because it “contained federal-law claims” and “state-law claims sufficiently related to the federal ones to come within that court’s supplemental jurisdiction.” Id. at *11. But the plaintiff’s post-removal “deletion of all federal claims deprived the District Court of federal-question jurisdiction,” as well as derivative “supplemental jurisdiction over the state claims.” Id. Thus, the plaintiff successfully “had reconfigured her suit to make it only about state law” and properly resolved in state court. Id.
