Concept
Exxon Mobil v. Allapattah
Supplemental jurisdiction
Exxon Mobil v. Allapattah
The preceding discussion of subsection (b) ended on a gap. The statute bars claims by Rule 19 and Rule 24 plaintiffs in diversity cases, yet it says nothing about plaintiffs joined permissively under Rule 20 or about members of a class. That silence mattered because, for most of the twentieth century, a plaintiff whose claim fell short of the jurisdictional amount could not piggyback on a co-plaintiff whose claim satisfied it. The Supreme Court resolved whether § 1367 changed that rule in Exxon Mobil Corp. v. Allapattah Services, Inc., and the decision is the controlling interpretation of the statute in diversity cases. The case is taught here in three steps: the facts and holding, the reasoning about what counts as a civil action of which the court has original jurisdiction, and the dispute over legislative history together with the Rule 20 gap.
Facts and Holding
Two consolidated cases reached the Court. In the first, about 10,000 Exxon dealers filed a class action in the Northern District of Florida, alleging a systematic scheme to overcharge them for fuel, and they invoked diversity jurisdiction.1 Each dealer's claim was for slightly less than the $75,000 minimum, and the jury returned a unanimous verdict for the plaintiffs before the district court certified the question whether it could hear the claims of class members who missed the amount.2 In the second case, a nine-year-old girl sued Star-Kist in Puerto Rico for severe injuries from slicing her finger on a tuna can, and her family joined to recover for emotional distress and medical expenses.3 The First Circuit found that only the girl had alleged the required amount, and it held that the family members could not stay in the case.4
The baseline the Court was reviewing came from two older decisions. Under Clark v. Paul Gray, Inc., two plaintiffs suing one defendant each had to meet the amount requirement, and the court would not add their claims together.5 Zahn v. International Paper Co. extended the same demand to class actions, so that a class member suing for less than the minimum was out even if the class representative's claim was large and the class's total damages ran into the millions.6 After Congress enacted § 1367 in 1990, courts disagreed about whether the statute left those cases untouched or displaced them.7 The Court had already divided four to four on the question once, which left the conflict in place until it took the Exxon cases.8
The Court held that where the other elements of jurisdiction are present and at least one named plaintiff satisfies the amount in controversy, § 1367 authorizes supplemental jurisdiction over the claims of other plaintiffs in the same Article III case or controversy, even if those claims fall below the statutory amount.9 It affirmed the Eleventh Circuit and reversed the First Circuit. The Court concluded that § 1367, by its plain text, overruled Clark and Zahn.10 The holding carries one condition, which is that supplemental jurisdiction cannot be used to defeat the complete diversity requirement.11
The two sides of that condition are easiest to see with an invented pair of cases. Suppose Priya, a Kansas citizen, sues a Texas defendant for $125,000 after a car accident, and her passenger Marcus, also from Kansas, joins as a co-plaintiff for $40,000 arising from the same collision. Priya's claim supplies original jurisdiction, and Marcus's claim is part of the same case or controversy, so both proceed.12 Change one fact and let Marcus be a Texas citizen like the defendant. Now diversity is incomplete, no claim in the action has original jurisdiction, and supplemental jurisdiction has nothing to attach to. The amount shortfall was forgiven in the first version, but a citizenship defect was not forgiven in the second.
Indivisibility and Contamination
The Court's reasoning begins with the text of § 1367(a), which is a broad grant of supplemental jurisdiction over other claims in the same case or controversy, so long as the action is one in which the district courts would have original jurisdiction.14 The whole dispute therefore reduces to a single question: does a diversity case in which some plaintiffs meet the amount and others do not present a "civil action of which the district courts have original jurisdiction"? If it does, subsection (a) reaches every claim in the same Article III case, including those that do not independently satisfy the amount.15 If it does not, subsection (a) is inapplicable and Clark and Zahn leave the court with no statutory basis to hear the smaller claims.16
The Court answered yes. A complaint that contains at least one claim satisfying the amount requirement, with no other jurisdictional defect, gives the court original jurisdiction over that claim beyond all question.17 The other claims in the complaint, over which the court may lack original jurisdiction, are of no moment, because original jurisdiction over a single claim is original jurisdiction over a "civil action" even if that action comprises fewer claims than the complaint pleaded.18 Only after that threshold is cleared does the court ask the second question, whether the remaining claims have a constitutional and statutory basis in subsection (a) and are free of the exceptions in subsections (b) and (c).19
That reasoning disposes of what can be called the contamination theory, the argument that one claim falling short of the amount spoils the whole action and leaves the court without original jurisdiction over any of it. The theory treats the action as indivisible for purposes of the amount requirement, so that one defective claim would defeat the threshold that subsection (a) requires. The Court's reading makes the threshold depend on whether the court has original jurisdiction over some claim, and a qualifying claim supplies that jurisdiction whatever else the complaint contains. The Court also refused to treat § 1367 as a mere codification of the pre-1990 case law, observing that jurisdictional statutes should not be read more broadly than their text warrants but should not be given an artificially narrow construction either.20
The amount requirement and the complete diversity requirement behave differently, and the difference explains why the holding stops where it does. The amount requirement screens out trivial disputes claim by claim, so a small claim that rides on a qualifying one adds little to the federal docket and is part of the same dispute anyway. Complete diversity protects against home-state bias in the case as a whole, which means that a single nondiverse party removes the original jurisdiction that supplemental jurisdiction would need to rest on. Hence the Court's condition that the case already be one of complete diversity.21
Legislative History and the Rule 20 Gap
The strongest argument for the opposite result came from legislative history. That history strongly suggested that Congress did not mean § 1367 to disturb the aggregation rules in Clark and Zahn, which would have left each plaintiff to meet the amount on their own.23 The Court gave the text priority over that history. It reasoned that ordinary principles of statutory construction apply, that the statute is read in light of its context, structure, and related provisions, and that no special canon requires Congress to speak with extraordinary clarity before modifying the rules of federal jurisdiction within constitutional bounds.24 Section 1367 did overrule Finley, and the Court saw no warrant for assuming it did only that.25
Subsection (b) then confirmed the reading instead of undercutting it. In diversity cases, § 1367(b) withholds supplemental jurisdiction over claims by plaintiffs proposed to be joined under Rule 19 or seeking to intervene under Rule 24, but nothing in its text withholds jurisdiction over plaintiffs permissively joined under Rule 20 or class members certified under Rule 23.26 The Court called the inference that those claims are covered "natural, indeed the necessary" one.27 For Rule 20 plaintiffs the inference is stronger still, because the same subsection expressly bars claims against defendants joined under Rule 20.28 Congress plainly considered Rule 20 when it wrote (b), and it chose to list the defendant side but not the plaintiff side.
The resulting statute is uneven, since a Rule 19 plaintiff is barred while a similarly situated Rule 20 plaintiff is not, and an exam answer should not try to repair that asymmetry. Under the Court's approach the enumerated list in (b) controls, and omissions from it are not filled in by reference to what Congress might have wanted.29 The remaining limits keep the holding narrow. The anchor claim must satisfy the amount, diversity must be complete, and the added claim must arise from the same case or controversy.30
Facts and Holding
The question in Exxon Mobil Corp. v. Allapattah Services, Inc. grew out of a rule about the amount in controversy, so the rule has to be understood first. Section 1332(a) requires that the matter in controversy exceed $75,000, and the Court explained that the requirement exists to keep diversity jurisdiction from flooding the federal courts with minor disputes.32 Before 1990 the Court treated that requirement as plaintiff-specific. In Clark v. Paul Gray, Inc., it held that when several plaintiffs sue, each must separately establish the jurisdictional amount, and the suit is dismissed as to any plaintiff who cannot.33 The result was a nonaggregation rule: two plaintiffs suing one defendant could not add their claims together, and each claim had to clear the line on its own.34 Zahn v. International Paper Co. carried that rule into class actions, so that a class member whose claim fell short had to be dismissed even though the class representative's claim was large.35
Congress added § 1367 to the Judicial Code in 1990, and lower courts then split on whether the new statute left Clark and Zahn in place. One side relied on legislative history suggesting that Congress did not mean to disturb the aggregation rules. The other side pointed to the text of § 1367(a), which grants jurisdiction over claims in the same case or controversy as a claim within original jurisdiction, and to subsection (b), which lists claims by Rule 19 and Rule 24 plaintiffs but says nothing of Rule 20 plaintiffs or class members.36 Two consolidated cases brought that split before the Supreme Court. In the first, about 10,000 Exxon dealers sued as a class in the Northern District of Florida, alleging a systematic scheme to overcharge them for fuel, and they invoked diversity jurisdiction.37 After a unanimous jury verdict for the plaintiffs, the district court certified the question whether it had properly exercised supplemental jurisdiction over class members who did not meet the jurisdictional minimum, and the Eleventh Circuit upheld that exercise.38
The second case reached the opposite result below. A nine-year-old girl sued Star-Kist in the District of Puerto Rico over a severe injury from slicing her finger on a tuna can, and her family joined to recover for emotional distress and certain medical expenses.39 The First Circuit found that only the girl had alleged the required amount. It reasoned that § 1367 applies only when the court has original jurisdiction over the action, and that in a diversity case original jurisdiction is lacking if one plaintiff fails to meet the amount.40 The family therefore had no path into federal court. Both cases asked the same thing, which was whether a plaintiff with a small claim could stay in federal court because another plaintiff's claim was large enough.
The Court held that she could. Where the other elements of jurisdiction are present and at least one named plaintiff satisfies the amount in controversy, § 1367 authorizes supplemental jurisdiction over the claims of other plaintiffs in the same Article III case or controversy, even if those claims fall below the statutory amount.41 The Court affirmed the Eleventh Circuit and reversed the First Circuit, and it concluded that § 1367, by its plain text, overruled Clark and Zahn.42 The reason the result is tolerable lies in what the amount requirement is for. Its job is to screen out trivial disputes, and a modest claim that arises from the same accident or business practice as a substantial one does not make the overall dispute any less significant. The holding also covers class actions, so a class member's smaller claim may ride along when a class representative's claim satisfies the amount.43
The holding has an anchor requirement and a diversity condition, and the following invented pair of cases shows how each works. Suppose Denise, a Kansas citizen, sues a Texas trucking company for $140,000 after a collision, and her passenger Omar, also a Kansas citizen, joins as a co-plaintiff seeking $30,000 for injuries from the same crash. Denise's claim supplies original jurisdiction, and Omar's claim is part of the same case or controversy, so the court hears both.44 Now reduce Denise's claim to $60,000. Neither plaintiff meets the amount, so no claim in the action is within original jurisdiction and supplemental jurisdiction has nothing to attach to. The first version succeeds because one claim anchors the action, and the second fails because none does. A different change to the first version produces a similar failure: if Omar were a Texas citizen like the defendant, complete diversity would be lost, because supplemental jurisdiction cannot be used to defeat the complete diversity requirement.45 The statute forgives an amount shortfall in an added plaintiff's claim, but it does not forgive a citizenship defect.
A separate statute now governs many large class actions. Congress has created a specialized form of diversity jurisdiction for class actions with more than $5 million in controversy, and that statute allows the claims of all class members to be aggregated to reach the figure.46 It supplements the rule in Exxon Mobil and does not replace it, and the Exxon Mobil analysis remains the framework for ordinary diversity cases with multiple plaintiffs.
Indivisibility and Contamination
The holding in Exxon Mobil depends on one phrase in § 1367(a): the statute applies only in a "civil action of which the district courts have original jurisdiction." Whether a diversity suit with one large claim and one small claim is such an action decides the case. If it is, subsection (a) can reach every claim in the same Article III case. If it is not, the statute never switches on and the small claim has no footing. The Court took up two arguments for the second answer and rejected both.48
The first argument is the "indivisibility theory." It treats the complaint as a single unit, so that the court has original jurisdiction over the civil action only if it has original jurisdiction over every claim in it.49 The Court called this theory easily dismissed, because it proves too much. In the foundational supplemental-jurisdiction case, Gibbs, the state claim had no independent federal footing, so if one such claim made the whole action fall outside original jurisdiction, Gibbs would have had no civil action to attach supplemental jurisdiction to at all. The theory also clashes with ordinary practice, in which a court that finds one party's claim defective dismisses that party and keeps the case. Clark itself dismissed the plaintiffs who missed the amount while keeping the one who met it.50 A court that really faced an indivisible action would have to dismiss everything.
The second argument is the "contamination theory," which does not insist on a single unit but holds that one defective claim or party spoils every other claim in the complaint.51 This theory is not absurd everywhere, and the Court treated it as correct in one setting. Its sensibility depends on what the particular jurisdictional requirement is for, so the analysis has to look at each requirement's purpose before deciding whether a defect spreads.
Complete diversity exists to give litigants a neutral forum when a state court might favor a home-state party. When citizens of the same state stand on opposite sides of the case, that worry disappears for the case as a whole, so the justification for a federal forum is gone for every claim in it.52 The consequence follows directly. Incomplete diversity destroys original jurisdiction over all claims, which leaves nothing for supplemental jurisdiction to adhere to, because a court must first have original jurisdiction over at least one claim before it can supplement anything.53 Contamination is therefore the right description of a diversity defect.
The amount in controversy serves a different purpose, which is to ensure that a dispute is important enough to deserve federal attention. A small claim does nothing to reduce the importance of a large claim sitting beside it, so no reason exists for the small claim to infect the large one.54 The Court also rejected the inference that because § 1332 contains both requirements, they must behave alike. The amount requirement has no inherent connection to diversity, and federal-question jurisdiction once carried its own amount requirement.55 Had that requirement been revived under § 1331, § 1367(a) would plainly supplement federal claims that fell short of it, and a rule that reaches that result cannot sensibly leave Zahn, which rested largely on Clark, standing.
The Court added a parallel from removal. In Chicago v. International College of Surgeons, a plaintiff's federal claims were enough to make the whole suit a "civil action" within the district court's original jurisdiction for purposes of the removal statute, even though related state claims were present, and the district court then took supplemental jurisdiction over those state claims.56 The same logic applies when the extra claims belong to additional parties. The removal parallel also confirms the diversity exception, since a case lacking complete diversity is not removable, which is consistent with the reading because failure of complete diversity contaminates every claim while a shortfall in amount does not.57
The Court also refused to treat the presence of additional parties as the cause of any contamination. Section 1367(a) itself speaks of supplemental jurisdiction over claims involving additional parties, and § 1367(b) would be pointless as to Rule 19 plaintiffs if their joinder already destroyed original jurisdiction over the action. A reading that let additional parties defeat the threshold would also leave the result in Finley undisturbed, which everyone agrees § 1367 was meant to change.58 The Court's conclusion was that when some but not all claims in a complaint are within original jurisdiction, the court has before it a civil action comprising the claims without a jurisdictional defect, and § 1367(a)'s threshold is met.59
A matched pair of invented cases shows how the two defects diverge. Suppose Nadia, an Oregon citizen, sues an Idaho company for $150,000 over a warehouse fire, and her neighbor Tomas, also from Oregon, joins to recover $20,000 for damage from the same fire. Nadia's claim anchors original jurisdiction, and Tomas's small claim does not spoil it, so the court may hear both under § 1367(a).60 Now change only Tomas's citizenship so that he is a citizen of Idaho, like the defendant. Diversity is no longer complete, so the court has original jurisdiction over no claim in the action, Nadia's included, and supplemental jurisdiction has nothing to attach to.61 The two versions differ in a single fact, and that fact determines whether the court can hear any part of the case.
The order matters because steps one and two decide whether any original jurisdiction exists at all, and only after that does supplemental jurisdiction have something to supplement.
Legislative History and the Rule 20 Gap
The holding in Exxon Mobil rests on the text of § 1367, but it did not go unchallenged. Two arguments pressed the other way. The first relied on a House committee report that seemed to say Congress meant to leave the old nonaggregation rule alone. The second offered a different reading of the phrase "civil action of which the district courts have original jurisdiction" that would have kept Clark and Zahn in force. How the Court answered both explains why the statute reads the way it does, and it also exposes an oddity in subsection (b) that still shapes how diversity cases are joined.
The committee report was the dissenters' strongest material. It described the new section as one that would authorize jurisdiction in a case like Finley and otherwise restore the understandings that existed before Finley. It then said subsection (b) was not meant to change the jurisdictional requirements of § 1332 in diversity-only class actions as they had been interpreted before Finley, and it cited Zahn.63 On the dissenters' view, that language showed Congress had a modest task in mind, which was to undo Finley, and committee reports are the usual place where busy legislators look to learn what a bill does.64 If the report is taken at its word, a diversity plaintiff whose claim falls short of the amount still has no way into federal court.
The majority answered that the enacted text is the authoritative statement of the law, and that extrinsic materials matter only when they shed reliable light on an otherwise ambiguous term. Because § 1367 was not ambiguous, the report never came into play.65 The Court then said that even if it were to consult the history, it would give the report little weight, for two reasons. The history was murkier than the report suggested, because the statute's text was drawn from a study-committee working paper whose footnote said the proposal would overrule Zahn and that this would be a good thing.66 And three law professors who took part in drafting had acknowledged that the text, on its face, overrules Zahn, and that the contrary passage in the report was an attempt to correct an oversight after the fact.67 The dissent replied that the professors had only been saying the text could be read too broadly, so that clarification in the report was appropriate.68 For exam purposes the dispute is a clean example of text against history, and the text won.
The dissent's alternative reading deserves a separate look because it shows what the majority's reading costs. On that view, the original-jurisdiction requirement in § 1367(a) takes in the whole of what § 1332 demands when it is applied in a diversity case. That includes complete diversity and the rule against aggregating plaintiffs' claims. A complaint would first have to clear that measure, and only then could supplemental jurisdiction attach to related claims.69 This reading explains why subsection (b) never mentions Rule 20 plaintiffs or Rule 23 class actions. A plaintiff whose claim is below the amount would already have failed at the threshold, so Congress would have had no reason to write an exception to turn that plaintiff away.70 The reading also lines up with the removal statute, which has long been read to incorporate the rules on complete diversity and amount in controversy.
The majority conceded that its own reading creates a puzzle. Subsection (b) withholds supplemental jurisdiction over claims by plaintiffs joined as needed parties under Rule 19, but it says nothing about plaintiffs permissively joined under Rule 20. The Court described the omission as odd but not absurd, and said that if it was an unintentional drafting gap, repairing it is Congress's job and not the courts'.71 It offered a possible reason for the difference. A nondiverse plaintiff might be left out of the original suit on purpose and then added later as a necessary party under Rule 19, which would sneak around the complete diversity rule. Congress may have wanted to close that route even though the contamination principle should already defeat it. The Court also pointed out that the dissent's reading has an anomaly of its own. If every plaintiff must satisfy § 1332 for the court to have original jurisdiction over the action, then the Rule 19 exception in (b) would serve no purpose.72
The gap has consequences for how a diversity case is built. When two plaintiffs sue one defendant, and one plaintiff's claim satisfies the amount, the second plaintiff's smaller claim comes in through supplemental jurisdiction. When one plaintiff sues two defendants, however, the plaintiff cannot use supplemental jurisdiction to add a claim against the second defendant unless that claim independently meets the amount.73 Imagine that Priya and Jun, both Arkansas citizens, sue one Ohio driver over a collision, with Priya claiming $120,000 and Jun $40,000. Jun's claim rides along. Now imagine that Marcus, an Arkansas citizen, sues two Ohio defendants over the same kind of collision, claiming $120,000 from the first and $40,000 from the second. Subsection (b) bars the claim against the second defendant, because it is a plaintiff's claim against a person made a party under Rule 20 and it does not meet the amount on its own. The only fact that changed is which side the extra claim sits on. Where two plaintiffs and two defendants are involved, the plaintiffs may be able to avoid the bar by filing separate single-defendant suits that the court then consolidates.74