The Supreme Court recently held in Royal Canin U.S.A., Inc. v. Wullschleger that even if a defendant properly removes a complaint from state to federal court based on federal question jurisdiction, a plaintiff’s post-removal amendment of the complaint to eliminate the basis for federal question jurisdiction will also deprive the federal court of supplemental jurisdiction over the remaining state-law claims. — S. Ct. —-, 2025 WL 96212 (Jan. 15, 2025).
In Royal Canin, a plaintiff brought a putative class action against a manufacturer of prescription dog food. The plaintiff alleged that she bought the food incorrectly thinking it contained medication not found in off-the-shelf products. According to the plaintiff, the defendant’s product is ordinary dog food, and defendant sold the product with a prescription not because the dog food’s ingredients make a prescription necessary, but rather to mislead consumers into overpaying for it. The plaintiff’s complaint—originally filed in state court—alleged that defendant violated Missouri consumer protection and antitrust laws as well as the Federal Food, Drug, and Cosmetic Act (FDCA).
The defendant properly removed the case to district court based on the asserted FDCA violations. As the Court noted, “[t]hat removal properly brought to the District Court not only Wullschleger’s FDCA claims, but also her factually intertwined state-law claims,” because 28 U.S.C. § 1367(a) provides that a district court may exercise supplemental jurisdiction over state-law claims sharing a common nucleus of operative fact with federal-law ones. Royal Canin, 2025 WL 96212, at *4–5. After removal, the plaintiff amended her complaint “to delete its every mention of the FDCA, leaving her state claims to stand on their own.” Id. at *4. The plaintiff then moved to remand her all-state-law complaint back to the state court. The district court denied the plaintiff’s request, which the Eighth Circuit subsequently reversed, finding that the plaintiff’s amendment eliminated any basis for federal jurisdiction. Defendant’s appeal to the Supreme Court followed.
The Court, in a unanimous opinion by Justice Kagan, affirmed the Eighth Circuit and held that “[i]f (as here) the plaintiff eliminates the federal-law claims that enabled removal, leaving only state-law claims behind, the court’s power to decide the dispute dissolves. With the loss of federal-question jurisdiction, the court loses as well its supplemental jurisdiction over the state claims.” Id. at *5. The Court reasoned that a host of statutes and prior cases link jurisdiction to the amended—rather than the initial—complaint: “[t]he amended complaint becomes the operative one; and in taking the place of what has come before, it can either create or destroy jurisdiction.” Id. at *7. Thus, if a complaint initially contains a federal question but a plaintiff later removes her federal-law claims (as the plaintiff did in Royal Canin), then there is no “federal anchor” for the case, “supplemental jurisdiction over the residual state claims disappears as well,” and the case must be remanded. Id. at *9.
The Court’s ruling resolved a circuit split, as courts in the First, Third, Fourth, Sixth, and Eleventh Circuits had reached the opposite conclusion and held that a post-removal amendment eliminating any federal questions could not divest a federal court of supplemental jurisdiction. Those cases had primarily relied on a footnote in Rockwell Int’l Corp. v. United States, which stated that “when a defendant removes a case to federal court based on the presence of a federal claim, an amendment eliminating the original basis for federal jurisdiction generally does not defeat jurisdiction.” 549 U.S. 457, 474 n.6 (2007). The Court acknowledged that such reliance on the Rockwell footnote was “both understandable and appropriate,” but it declined to follow this dictum from Rockwell—which had no bearing on the Court’s analysis in Rockwell and was “barely reasoned”—because it could not be squared with extensive authority suggesting that “the plaintiff’s excision of her federal-law claims deprives the district court of its authority to decide the state-law claims remaining.” Royal Canin, 2025 WL 96212, at *10–11 & n.10.
The Royal Canin opinion addressed only supplemental jurisdiction after a post-removal amendment to eliminate federal question jurisdiction, and it did not directly address diversity jurisdiction or the Class Action Fairness Act. For instance, it has long been the rule with removal for diversity jurisdiction that a district court must evaluate the state court complaint at the time of removal to determine its jurisdiction, Pullman Co. v. Jenkins, 305 U.S. 534, 537 (1939), and courts have been skeptical to allow post-removal attempts to amend pleadings to destroy diversity. We suspect courts will continue to adhere to that precedent. All sources of federal jurisdiction should be considered when analyzing grounds for removal.