Supplemental Jurisdiction
Federal courts may exercise jurisdiction over state-law claims that form part of the same constitutional case or controversy as a claim over which the court has original jurisdiction, even if the state claim could not independently invoke federal jurisdiction.
Elements / Test
28 U.S.C. § 1367 (codifying United Mine Workers v. Gibbs):
§ 1367(a) — Grant: Supplemental jurisdiction exists over claims that are part of the same Article III “case” — sharing a “common nucleus of operative fact” with the anchor claim.
§ 1367(b) — Diversity exception: In diversity-only cases, no supplemental jurisdiction over claims by plaintiffs against persons made parties under Rules 14, 19, 20, or 24, or claims by persons proposed to be joined under Rules 19 or 24, if doing so would destroy complete diversity (Strawbridge rule).
§ 1367(c) — Discretionary decline: Court may decline supplemental jurisdiction if:
- Claim raises novel/complex state law question
- State claim substantially predominates
- Original federal claims dismissed
- Other compelling reasons
Amount aggregation: Under Exxon Mobil v. Allapattah, supplemental jurisdiction allows claims of additional plaintiffs below the $75,000 threshold if one plaintiff satisfies it.
Exceptions and Edge Cases
- Counterclaims: Compulsory counterclaims always within supplemental jurisdiction; permissive counterclaims require independent jurisdiction
- Third-party claims (Rule 14): Generally within supplemental jurisdiction; § 1367(b) limits plaintiff’s claims against Rule 14 defendants in diversity
- Class actions: CAFA provides independent basis; but for non-CAFA class actions, § 1367(b) and Zahn (not overruled) may limit absent class member claims
Policy Rationale
Judicial efficiency — allows all aspects of a dispute to be resolved in one proceeding; prevents piecemeal litigation.
Key Cases
| Case | Rule |
|---|---|
| United Mine Workers v. Gibbs (1966) | Constitutional basis for pendant jurisdiction — common nucleus of operative fact |
| Exxon Mobil Corp. v. Allapattah Services, Inc. (2005) | § 1367 overrules Zahn; supplemental jurisdiction over additional plaintiffs below $75K threshold |
| Finley v. United States (1989) | (Pre-§ 1367) No pendant party jurisdiction over unrelated claims; Congress enacted § 1367 in response |