The Dog Food Case That Rewired Federal Jurisdiction

How a pet‑food lawsuit became the Supreme Court’s cleanest answer yet to a messy removal problem—and what it means for every litigator who plays the forum game.

The Supreme Court’s unanimous decision in Royal Canin U.S.A., Inc. v. Wullschleger (2025) sets a bright‑line rule: if a plaintiff amends after removal to delete all federal claims, the federal court loses supplemental jurisdiction and must remand to state court. It’s a procedural reset button that strengthens plaintiffs’ forum control, narrows defendants’ ability to anchor cases in federal court, and standardizes a long‑contested corner of civil litigation.^[1][2]

Visual Case Brief (One‑Screen Summary)

The Backstory: A Pet‑Food Label, a Federal Hook, and a Quick Edit

The suit started like many consumer cases: buyers alleged that “prescription‑only” dog food was marketed as something special (and priced accordingly) even though it allegedly contained no medicine. They filed a mixed bag of state‑law and federal claims. The federal references (including the FDCA) made the case removable under § 1441. Once in federal court, the plaintiffs performed the move at the heart of this case: they amended the complaint to delete every federal mention and asked for a remand. The district court refused and ultimately dismissed on the merits; the Eighth Circuit reversed, holding the amendment destroyed the only federal hook and, with it, supplemental jurisdiction over the remaining state claims. The Supreme Court took the split and agreed with the Eighth Circuit.^[1][4]

The 9–0 Rule: Jurisdiction Follows the Live Pleading

The opinion is elegantly simple:

• Subject‑matter jurisdiction tracks the operative complaint, not the ghost of pleadings past. That’s straight out of Rockwell: when a plaintiff voluntarily amends, courts look to the amended complaint to determine jurisdiction.^[1]

• Section 1367’s text does the heavy lifting. Supplemental jurisdiction exists only in an action “of which the district courts have original jurisdiction.” When the plaintiff amends away every federal claim, there’s no original federal question left—so no supplemental jurisdiction either. Crucially, § 1367(c) permits discretion to keep state claims after the court dismisses federal ones, but it says nothing about plaintiff‑initiated amendments. The omission, the Court says, matters.^[1]

• The Court declines to build doctrine on a Rockwell footnote often cited to support retention after removal. That language was dictum and can’t carry the weight of a contrary rule.^[1]

Bottom line: amendment → no federal claim → no supplemental jurisdiction → remand. No “close calls,” no discretionary balancing.

What This Decision Is—and Is Not

• Is: A clear federal‑question removal rule. If removal rode in on a federal claim, and the plaintiff later amends to delete that claim, the case must go back to state court.^[1][2]

• Is Not: A rewrite of diversity or CAFA removal. Those regimes have their own timing rules and doctrines (e.g., Pullman Co. v. Jenkins), and Royal Canin expressly addresses only the post‑removal amendment of federal‑question cases.^[5]

• Also: The decision abrogates contrary approaches in multiple circuits, making the rule uniform and removing a trap that generated expensive satellite litigation.^[6]

The Practical Shockwave: Forum Power, Yo‑Yo Risk, and New Litigation Math

1) Plaintiffs just gained a reliable exit ramp

If your client prefers a state forum, Royal Canin validates a crisp tactic: file broad, remove if they must, then amend and remand. Expect more early amendments designed to lock venue in state court for consumer, employment, privacy, and tort cases with overlapping state and federal theories.^[2][7]

2) Defendants face a harder time anchoring in federal court

Removal on federal‑question grounds is now fragile. If diversity or CAFA isn’t available, defendants must assume the case might boomerang back after a fast amendment. That affects whether to invest in federal‑court motions (12(b)(6), class certification scoping, MDL maneuvers) that may never culminate in a federal judgment.^[2][6]

3) Timing and gatekeeping matter

Rule 15 and scheduling orders give judges tools to deny leave for late, prejudicial, or bad‑faith amendments. If the plaintiff waits until after critical federal rulings, expect sharper defense arguments that the amendment is gamesmanship. Still, when the amendment is permitted, remand isn’t optional.^[7]

Strategy Matrix (Bookmark This)

How to Adapt Your Playbook—Now

For Plaintiffs

• Draft with options. If you include federal theories, preserve the ability to surgically remove them early.

• Move fast. Amend before the federal court invests heavily; you’ll avoid fights over leave and reduce accusations of gamesmanship.

• Mind preclusion. If you’ve taken substantive rulings, consider whether issue preclusion will shadow you into state court.

For Defendants

• Choose your hook wisely. If diversity or CAFA is viable, it’s far more resilient than a thin federal question.

• Litigate the amendment. After the Rule 15 free‑amendment window, oppose leave if timing/prejudice suggests forum shopping.

• Sequence matters. In close cases, consider pushing for a merits dismissal of federal claims rather than inviting a plaintiff‑driven amendment that forces remand.

Why This Will Show Up in Your Cases

This isn’t niche. Consumer, wage‑and‑hour, privacy, antitrust‑adjacent state statutes—many are pled alongside federal analogs. By clarifying that the amended complaint controls jurisdiction in removed cases, the Court effectively re‑balances forum choice toward plaintiffs and will shift a non‑trivial slice of mixed‑claim litigation back to state courts. Expect more state‑court class actions to stay put and more defense teams to recalibrate removal memos, especially where federal claims are marginal add‑ons. Amicus activity—states supporting plaintiffs’ ability to keep purely state‑law cases in state court—signals that federalism and forum choice will keep drawing attention in the next docket.^[8]

The Bottom Line

Royal Canin delivers what civil procedure rarely does: a bright line. After removal, if the federal claims disappear by amendment, so does federal jurisdiction. The rest is strategy. Whoever masters the timing—and the operative complaint—wins the forum.

Endnotes

1. Slip Opinion (Jan. 15, 2025). The Court holds that an amendment eliminating federal claims after removal divests supplemental jurisdiction; remand required; opinion by Kagan, J., unanimous. Supreme Court

2. SCOTUSblog Case Page. Holding, vote, and summary of the Court’s ruling. SCOTUSblog

3. Supreme Court Docket, No. 23‑677. Argument (Oct. 7, 2024), decision date, counsel of record, and judgment (affirmed). Supreme Court

4. Eighth Circuit Decision (July 31, 2023). Explains why the post‑removal amendment eliminated federal‑question jurisdiction and thus supplemental jurisdiction; sets up the circuit split. Eighth Circuit Court of Appeals

5. Inside Class Actions (Jan. 17, 2025). Clarifies that Royal Canin addresses federal‑question removal; it does not change diversity or CAFA doctrines (e.g., Pullman Co. v. Jenkins timing rules). Inside Class Actions

6. Thompson Coburn (Jan. 17, 2025). Notes that the ruling abrogates contrary law in several circuits, creating a uniform national rule. Thompson Coburn LLP

7. Winston & Strawn (Feb. 21, 2025). Case background (FDCA hook; amendment to strike federal references) and practitioner takeaways on forum control. Winston & Strawn

8. Reuters Coverage (Aug. 13, 2024). Amicus support by 22 states; broader federalism backdrop for the forum‑choice fight. Reuters