Subject Matter Jurisdiction Guide
Subject matter jurisdiction is the court's authority to hear a particular type of case or controversy. Unlike personal jurisdiction, which concerns power over the parties, subject matter jurisdiction concerns the court's competence to adjudicate the subject of the dispute. It cannot be waived by the parties, can be raised at any time (even on appeal), and its absence renders a judgment void. Federal courts are courts of limited subject matter jurisdiction — they can only hear cases falling within the categories defined by Article III of the Constitution and authorized by Congress.
The two primary bases for federal subject matter jurisdiction are federal question jurisdiction under 28 U.S.C. Section 1331 and diversity jurisdiction under 28 U.S.C. Section 1332. Federal question jurisdiction exists when a case arises under the Constitution, laws, or treaties of the United States. Diversity jurisdiction exists when the parties are citizens of different states (or a state and a foreign country) and the amount in controversy exceeds $75,000. Additional bases include supplemental jurisdiction (28 U.S.C. Section 1367), which allows federal courts to hear related state-law claims, and removal jurisdiction (28 U.S.C. Section 1441), which allows defendants to transfer cases from state to federal court.
A critical feature of subject matter jurisdiction is that parties cannot confer it by consent or waiver. If a federal court lacks subject matter jurisdiction, it must dismiss the case — even if neither party raises the issue. Courts have an independent obligation to verify their own subject matter jurisdiction, and a judgment rendered without it is void and subject to collateral attack. This distinguishes subject matter jurisdiction from personal jurisdiction and venue, both of which can be waived.
On civil procedure exams, subject matter jurisdiction questions often require students to analyze multiple bases simultaneously. A single case may involve federal question claims, diversity claims, and supplemental state-law claims. Students must determine whether each claim independently satisfies a basis for federal jurisdiction or whether it can piggyback on another claim through supplemental jurisdiction. The interplay between these bases — and the statutory exceptions in Section 1367(b) — is one of the most heavily tested areas in civil procedure.
Key Elements
- 1
Federal Question Jurisdiction (28 U.S.C. Section 1331)
The case must arise under the Constitution, laws, or treaties of the United States. The federal question must appear on the face of the plaintiff's well-pleaded complaint — a federal defense is not sufficient.
- 2
Diversity Jurisdiction (28 U.S.C. Section 1332)
Complete diversity must exist between all plaintiffs and all defendants (no plaintiff may share citizenship with any defendant), and the amount in controversy must exceed $75,000, exclusive of interest and costs.
- 3
Non-Waivability
Subject matter jurisdiction cannot be created by consent, waiver, or estoppel. Courts must dismiss for lack of subject matter jurisdiction at any stage of the litigation, even if no party raises the issue.
- 4
Supplemental Jurisdiction (28 U.S.C. Section 1367)
Federal courts may exercise jurisdiction over additional claims that are part of the same case or controversy as a claim within the court's original jurisdiction, subject to statutory exceptions.
- 5
Amount in Controversy
For diversity jurisdiction, the plaintiff must allege in good faith that the amount in controversy exceeds $75,000. Courts accept the plaintiff's allegation unless it appears to a legal certainty that the claim is for less.
Step-by-Step Analysis Flowchart
- Step 1: Identify all claims in the case and the parties asserting them.
- Step 2: For each claim, determine whether it arises under federal law (federal question jurisdiction under Section 1331).
- Step 3: Apply the well-pleaded complaint rule: Does a federal issue appear on the face of the complaint, not merely as an anticipated defense?
- Step 4: If no federal question, assess diversity jurisdiction: Determine the citizenship of every party (domicile for individuals; incorporation + principal place of business for corporations).
- Step 5: Check for complete diversity: No plaintiff may share state citizenship with any defendant at the time the complaint is filed.
- Step 6: Verify the amount in controversy exceeds $75,000, exclusive of interest and costs.
- Step 7: For claims lacking an independent basis, analyze supplemental jurisdiction under Section 1367(a): Are the state-law claims part of the same case or controversy (common nucleus of operative fact)?
- Step 8: Check Section 1367(b) exceptions: In diversity-only cases, supplemental jurisdiction does not extend to claims by plaintiffs against parties joined under Rules 14, 19, 20, or 24, or to claims by persons proposed to be joined as plaintiffs under Rule 19 or seeking to intervene under Rule 24, if it would destroy complete diversity.
- Step 9: Consider whether the court should exercise discretionary declination under Section 1367(c) (novel state issue, state claim predominates, original jurisdiction claims dismissed, or exceptional circumstances).
- Step 10: Confirm that no jurisdictional defect exists that would require dismissal under Rule 12(b)(1).
Key Rules
- Federal courts are courts of limited jurisdiction and must have a statutory and constitutional basis for every claim they adjudicate (Kokkonen v. Guardian Life Insurance Co.).
- Subject matter jurisdiction cannot be waived or conferred by consent of the parties — courts must raise it sua sponte if the parties do not (Capron v. Van Noorden).
- The well-pleaded complaint rule limits federal question jurisdiction to cases where the federal issue appears on the face of the plaintiff's complaint (Louisville & Nashville Railroad Co. v. Mottley).
- Complete diversity requires that no plaintiff share citizenship with any defendant; minimal diversity (at least one diverse pair) is insufficient under Section 1332 (Strawbridge v. Curtiss).
- The amount in controversy is tested at the time of filing and is accepted unless it appears to a legal certainty that the plaintiff cannot recover more than $75,000 (St. Paul Mercury Indemnity Co. v. Red Cab Co.).
- A judgment rendered without subject matter jurisdiction is void and may be attacked collaterally at any time.
Common Exam Patterns
Plaintiff brings a state-law claim that requires interpretation of a federal statute — tests the embedded federal question doctrine (Grable & Sons Metal Products).
Multiple plaintiffs sue a single defendant, with some plaintiffs sharing citizenship with the defendant — tests complete diversity and supplemental jurisdiction under Exxon Mobil Corp. v. Allapattah Services.
Plaintiff aggregates multiple claims to meet the amount-in-controversy requirement — tests aggregation rules (single plaintiff may aggregate; multiple plaintiffs generally may not).
A federal claim is dismissed early in the case, leaving only supplemental state-law claims — tests discretionary declination under Section 1367(c).
Plaintiff sues in federal court on diversity grounds, then a third-party claim or crossclaim destroys complete diversity — tests the Section 1367(b) exceptions.
An LLC or partnership is a party — tests that citizenship for unincorporated entities is determined by the citizenship of all members, not the state of formation.
Landmark Cases
Louisville & Nashville Railroad Co. v. Mottley (1908)
Established the well-pleaded complaint rule: federal question jurisdiction requires that the federal issue appear on the face of the plaintiff's complaint, not merely as an anticipated defense or counterclaim.
Strawbridge v. Curtiss (1806)
Established the complete diversity rule: diversity jurisdiction under Section 1332 requires that every plaintiff be diverse from every defendant, not merely that one pair of opposing parties be diverse.
Exxon Mobil Corp. v. Allapattah Services, Inc. (2005)
Held that supplemental jurisdiction under Section 1367 permits federal courts to exercise jurisdiction over additional plaintiffs in a diversity case even if those plaintiffs do not independently meet the amount-in-controversy requirement, as long as at least one plaintiff does.
Grable & Sons Metal Products, Inc. v. Darue Engineering (2005)
Articulated the test for when a state-law claim with an embedded federal issue qualifies for federal question jurisdiction: the federal issue must be (1) necessarily raised, (2) actually disputed, (3) substantial, and (4) capable of resolution without disrupting the federal-state balance.
Tips for Success
- Always check subject matter jurisdiction first in any federal court analysis — if the court lacks it, nothing else matters.
- The well-pleaded complaint rule is counterintuitive: even if everyone knows the case will turn on federal law, jurisdiction is determined by what appears in the complaint, not the answer or reality.
- For diversity jurisdiction, remember that citizenship is determined at the time the complaint is filed, not at the time of the events giving rise to the claim.
- LLCs, partnerships, and other unincorporated entities take the citizenship of all their members — this is a frequent exam trap that destroys diversity.
- Aggregation rules differ: a single plaintiff can aggregate claims against a single defendant, but multiple plaintiffs generally cannot aggregate their separate claims.
- Section 1367(b) exceptions only apply in diversity-only cases, not when the court also has federal question jurisdiction.
- When in doubt, remember the presumption: federal courts presume they lack jurisdiction, and the party invoking federal jurisdiction bears the burden of establishing it.