Whether, in a diversity action with complete diversity, a federal court may exercise supplemental jurisdiction over plaintiffs whose claims fall below the amount-in-controversy requirement when at least one named plaintiff has a claim exceeding that requirement.
Holding
Yes. Under 28 U.S.C. § 1367(a), a district court may hear related claims of additional diverse plaintiffs even though those claims do not independently meet the amount-in-controversy requirement, provided at least one plaintiff's claim does and all claims form part of the same Article III case or controversy.
Reasoning
Section 1367(a) broadly grants supplemental jurisdiction in any civil action of which the district court has original jurisdiction over all other claims that are sufficiently related to the jurisdiction-conferring claims. A complaint containing at least one claim that satisfies the amount-in-controversy requirement gives the district court original jurisdiction over that claim and therefore over a “civil action” within the meaning of § 1367(a). The presence of other claims lacking an independent jurisdictional basis does not erase original jurisdiction over the qualifying claim.
The Court rejected the view that a civil action is jurisdictionally indivisible—that every claim must independently satisfy § 1332 before supplemental jurisdiction can attach. That view is incompatible with supplemental jurisdiction itself, which permits a court with original jurisdiction over one claim to hear related claims that lack an independent jurisdictional basis. It also conflicts with the established practice of dismissing only jurisdictionally defective parties or claims rather than dismissing an entire action.
The Court distinguished the amount-in-controversy requirement from complete diversity. A nondiverse party destroys diversity jurisdiction because it defeats the basic purpose of diversity jurisdiction: providing a neutral federal forum where state-court bias may be feared. But a claim below the jurisdictional amount does not undermine the importance of another plaintiff's qualifying claim. Thus, lack of complete diversity contaminates the action, while an amount defect ordinarily remains claim-specific.
This reading overruled the earlier rules of Clark v. Paul Gray, Inc. and Zahn v. International Paper Co., which had required each plaintiff, including each class member, to satisfy the amount-in-controversy requirement independently. Once § 1367(a)'s threshold is met, the statute supplies supplemental jurisdiction for all related claims unless a statutory exception applies.