Subject Matter Jurisdiction Explained

Subject matter jurisdiction (SMJ) asks whether the court has authority over the kind of dispute. Personal jurisdiction asks whether it has authority over the particular defendant. Venue asks whether this district is a proper place to litigate. Only the first is constitutionally non-negotiable: personal jurisdiction and venue are personal privileges that a defendant waives by failing to raise them in the first Rule 12 response, while SMJ can be raised at any time by any party or by the court itself under Fed. R. Civ. P. 12(h)(3).

State trial courts of general jurisdiction are the default. They can hear essentially any claim, including most federal claims, unless Congress has made federal jurisdiction exclusive (patent and copyright under 28 U.S.C. § 1338, bankruptcy, federal antitrust, securities exchange claims). Federal district courts are the opposite: they are courts of limited jurisdiction and the party invoking federal jurisdiction bears the burden of establishing it.

Federal SMJ requires two things stacked on each other. First, the case must fall within Article III, § 2, which the Supreme Court has read generously; Osborn v. Bank of the United States, 22 U.S. (9 Wheat.) 738 (1824), permits jurisdiction whenever federal law forms an 'ingredient' of the case. Second, Congress must have granted the jurisdiction by statute, and the statutory grants are narrower than Article III allows. Verlinden B.V. v. Central Bank of Nigeria, 461 U.S. 480 (1983), illustrates the two-step structure.

Section 1331 gives district courts jurisdiction over civil actions arising under the Constitution, laws, or treaties of the United States. The threshold filter is the well-pleaded complaint rule from Louisville & Nashville Railroad Co. v. Mottley, 211 U.S. 149 (1908): the federal issue must appear on the face of a properly pleaded complaint. An anticipated federal defense does not count, and neither does a federal counterclaim. Mottley is the classic trap — the plaintiffs' contract claim was state law even though everyone knew the railroad would defend on a federal statute.

Most § 1331 cases are easy under the Holmes creation test from American Well Works Co. v. Layne & Bowler Co., 241 U.S. 257 (1916): a suit arises under the law that creates the cause of action. A Title VII claim or a § 1983 claim arises under federal law; a negligence claim does not.

The hard category is a state-law claim with an embedded federal issue. Grable & Sons Metal Products, Inc. v. Darue Engineering & Manufacturing, 545 U.S. 308 (2005), and Gunn v. Minton, 568 U.S. 251 (2013), supply a four-part test: the federal issue must be (1) necessarily raised, (2) actually disputed, (3) substantial to the federal system as a whole, and (4) resolvable in federal court without disturbing the congressionally approved federal-state balance. Substantiality is where most claims fail — the legal-malpractice-about-patent-law claim in Gunn was backward-looking and case-specific, so it was not substantial. Note also Merrell Dow Pharmaceuticals Inc. v. Thompson, 478 U.S. 804 (1986): the absence of a federal private right of action strongly cuts against jurisdiction.

Section 1332(a) requires complete diversity of citizenship plus more than $75,000 in controversy, exclusive of interest and costs. Complete diversity, from Strawbridge v. Curtiss, 7 U.S. (3 Cranch) 267 (1806), means no plaintiff may share a state of citizenship with any defendant. This is a statutory construction, not a constitutional one; Article III requires only minimal diversity, which is why the Class Action Fairness Act can reach further.

Citizenship rules are mechanical, so learn them cold. An individual is a citizen of the state of her domicile: physical presence plus intent to remain indefinitely, changed only by satisfying both elements, as illustrated in Mas v. Perry, 489 F.2d 1399 (5th Cir. 1974). A corporation is a citizen of every state of incorporation and of its single principal place of business, which Hertz Corp. v. Friend, 559 U.S. 77 (2010), defines as the 'nerve center' — the headquarters where officers direct and control the company. Unincorporated entities, including partnerships and LLCs, take the citizenship of every member, under Carden v. Arkoma Associates, 494 U.S. 185 (1990). A limited partnership with one Delaware limited partner is a Delaware citizen.

Citizenship is measured at the moment of filing. Post-filing changes neither create nor destroy jurisdiction; Grupo Dataflux v. Atlas Global Group, L.P., 541 U.S. 567 (2004). For the amount in controversy, the plaintiff's good-faith allegation controls unless it appears to a legal certainty that recovery cannot exceed the threshold, under St. Paul Mercury Indemnity Co. v. Red Cab Co., 303 U.S. 283 (1938). A single plaintiff may aggregate all claims against a single defendant; separate plaintiffs generally may not aggregate, except for a common undivided interest.

Two judge-made carve-outs survive: federal courts will not issue divorce, alimony, or child custody decrees, Ankenbrandt v. Richards, 504 U.S. 689 (1992), and will not probate a will or administer an estate, though Marshall v. Marshall, 547 U.S. 293 (2006), confined the probate exception narrowly.

Section 1367(a) codifies United Mine Workers v. Gibbs, 383 U.S. 715 (1966): once a claim supports original jurisdiction, the court may hear all other claims so related that they form part of the same case or controversy — practically, claims arising from a common nucleus of operative fact.

Section 1367(b) then removes certain claims in cases where original jurisdiction rests solely on diversity, to prevent plaintiffs from evading the complete diversity and amount requirements. It bars claims by plaintiffs against persons joined under Rules 14, 19, 20, or 24, and claims by plaintiffs joined under Rule 19 or intervening under Rule 24, when exercising jurisdiction would be inconsistent with § 1332. Read § 1367(b) literally on an exam: it restricts claims by plaintiffs, not by defendants.

Exxon Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546 (2005), is the key gloss. If at least one plaintiff satisfies the amount in controversy, § 1367 supplies jurisdiction over co-plaintiffs joined under Rule 20 or class members whose claims fall short. But a citizenship defect is different: a contamination of complete diversity destroys original jurisdiction over the whole action, so supplemental jurisdiction cannot rescue it.

Section 1367(c) is discretionary. A court may decline supplemental jurisdiction if the state claim raises a novel or complex state issue, substantially predominates, all claims with original jurisdiction have been dismissed, or in exceptional circumstances with compelling reasons. Dismissal of the federal anchor claim early in the case is the most commonly invoked ground.

Under 28 U.S.C. § 1441(a), a defendant may remove a state-court action that could originally have been filed in federal court. Removability is judged by the well-pleaded complaint, so a federal defense or counterclaim does not create it, and Home Depot U.S.A., Inc. v. Jackson, 139 S. Ct. 1743 (2019), holds that a third-party counterclaim defendant is not a 'defendant' entitled to remove.

The forum defendant rule in § 1441(b)(2) blocks removal of a diversity case if any properly joined and served defendant is a citizen of the forum state; it does not apply to federal question cases and, because it is a procedural defect rather than a jurisdictional one, it is waived if not raised within 30 days. Whether a defendant may 'snap remove' before service is a live split: the Second, Third, and Fifth Circuits read the 'joined and served' language literally to permit it, and district courts elsewhere divide.

Timing rules live in § 1446: 30 days from receipt of the initial pleading or from the first paper showing removability, and an absolute one-year cap on diversity removals under § 1446(c)(1) unless the plaintiff acted in bad faith to prevent removal. All properly joined and served defendants must consent. Under § 1447(c), a motion to remand for any defect other than SMJ must come within 30 days, but an SMJ defect requires remand at any time, and § 1447(d) makes most remand orders unreviewable on appeal.

SMJ protects the structural allocation of power between federal and state courts, not the parties' convenience, so consent is irrelevant. Capron v. Van Noorden, 6 U.S. (2 Cranch) 126 (1804), let the losing plaintiff — the very party who had invoked federal jurisdiction — overturn his own judgment on appeal because diversity had never been properly alleged.

The one meaningful limit is finality. Caterpillar Inc. v. Lewis, 519 U.S. 61 (1996), holds that when a diversity defect existing at removal is cured before judgment (there, by dismissal of the non-diverse party), the judgment stands; the interest in finality outweighs the initial defect. Contrast Grupo Dataflux, where the defect was never cured before judgment and reversal followed.

Distinguish true jurisdictional requirements from elements of a claim. Arbaugh v. Y&H Corp., 546 U.S. 500 (2006), adopts a bright-line rule: a statutory threshold is jurisdictional only if Congress clearly says so. Title VII's 15-employee requirement is a merits element, so a defendant who loses at trial cannot resurrect it post-verdict as a jurisdictional objection.

Go claim by claim and party by party. For each claim, ask whether it independently supports § 1331 or § 1332; if not, ask whether § 1367 covers it, then run § 1367(b) if diversity is the sole basis, then note § 1367(c) discretion. Professors award points for the sequence, not just the conclusion.

State the citizenship of every party explicitly, using the correct rule for the entity type, and fix the time of filing (or the time of filing plus the time of removal, for removed cases). Then address the amount in controversy separately. Finish by naming the procedural consequence: dismissal without prejudice under Rule 12(h)(3), remand under § 1447(c), or a Rule 12(b)(1) motion that may be facial or factual — a factual attack lets the court weigh evidence outside the pleadings without converting to summary judgment.

One area genuinely varies: state-court SMJ. Some states use amount-based tiers (small claims, limited and unlimited civil divisions), some maintain separate equity courts like Delaware's Court of Chancery, and naming conventions differ — New York's Supreme Court is the general trial court. If your course covers state practice, check your jurisdiction's constitution and judiciary code rather than reasoning from the federal model.