Whether the court of appeals erred in finding federal question jurisdiction over a state-law class action complaint alleging marketing of fake pet food products

QUESTION(S) PRESENTED Petitioners’ class action complaint brought in state court seeking relief under Missouri law for respondents’ marketing of fake prescription pet food products raised neither a substantial nor a disputed federal question. In ruling nonetheless that federal courts have subject-matter jurisdiction over this suit, did the court of appeals introduce chaos into this Court’s coherent jurisprudence about when federal question jurisdiction will lie over state-law claims? ti STATEMENT OF RELATED CASES None