JUSTICE BREYER, delivered the opinion of the Court.

The Class Action Fairness Act of 2005 (CAFA) provides that the federal "district courts shall have original jurisdiction" over a civil "class action" if, among other things, the "matter in controversy exceeds the sum or value of $5,000,000." 28 U. S. C. §§1332(d)(2), (5). The statute adds that "to determine whether the matter in controversy exceeds the sum or value of $5,000,000," the "claims of the individual class members shall be aggregated." §1332(d)(6).

The question presented concerns a class-action plaintiff who stipulates, prior to certification of the class, that he, and the class he seeks to represent, will not seek damages that exceed $5 million in total. Does that stipulation remove the case from CAFA's scope? In our view, it does not.

I

In April 2011 respondent, Greg Knowles, filed this proposed class action in an Arkansas state court against petitioner, the Standard Fire Insurance Company. Knowles claimed that, when the company had made certain homeowner's insurance loss payments, it had unlawfully failed to include a general contractor fee. And Knowles sought to certify a class of "hundreds, and possibly thousands" of similarly harmed Arkansas policyholders. App. to Pet. for Cert. 66. In describing the relief sought, the complaint says that the "Plaintiff and Class stipulate they will seek to recover total aggregate damages of less than five million dollars." Id., at 60. An attached affidavit stipulates that Knowles "will not at any time during this case . . . seek damages for the class . . . in excess of $5,000,000 in the aggregate." Id., at 75.

On May 18, 2011, the company, pointing to CAFA's jurisdictional provision, removed the case to Federal District Court. See 28 U. S. C. §1332(d); §1453. Knowles argued for remand on the ground that the District Court lacked jurisdiction. He claimed that the "sum or value" of the "amount in controversy" fell beneath the $5 million threshold. App. to Pet. for Cert. 2. On the basis of evidence presented by the company, the District Court found that that the "sum or value" of the "amount in controversy" would, in the absence of the stipulation, have fallen just above the $5 million threshold. Id., at 2, 8. Nonetheless, in light of Knowles' stipulation, the court concluded that the amount fell beneath the threshold. The court consequently ordered the case remanded to the state court. Id., at 15.

The company appealed from the remand order, but the Eighth Circuit declined to hear the appeal. Id., at 1. See 28 U. S. C. §1453(c)(1) (2006 ed., Supp. V) (providing discretion to hear an appeal from a remand order). The company petitioned for a writ of certiorari. And, in light of divergent views in the lower courts, we granted the writ. Compare Frederick v. Hartford Underwriters Ins. Co., 683 F. 3d 1242, 1247 (CA10 2012) (a proposed class-action representative's "attempt to limit damages in the complaint is not dispositive when determining the amount in controversy"); with Rolwing v. Nestle Holdings, Inc., 666 F. 3d 1069, 1072 (CA8 2012) (a precertification "binding stipulation limiting damages sought to an amount not exceeding $5 million can be used to defeat CAFA jurisdiction").

II

CAFA provides the federal district courts with "original jurisdiction" to hear a "class action" if the class has more than 100 members, the parties are minimally diverse, and the "matter in controversy exceeds the sum or value of $5,000,000." 28 U. S. C. §§1332(d)(2), (5)(B). To "determine whether the matter in controversy" exceeds that sum, "the claims of the individual class members shall be aggregated." §1332(d)(6). And those "class members" include "persons (named or unnamed) who fall within the definition of the proposed or certified class." §1332(d) (1)(D) (emphasis added).

As applied here, the statute tells the District Court to determine whether it has jurisdiction by adding up the value of the claim of each person who falls within the definition of Knowles' proposed class and determine whether the resulting sum exceeds $5 million. If so, there is jurisdiction and the court may proceed with the case. The District Court in this case found that resulting sum would have exceeded $5 million but for the stipulation. And we must decide whether the stipulation makes a critical difference.

In our view, it does not. Our reason is a simple one: Stipulations must be binding. See 9 J. Wigmore, Evidence §2588, p. 821 (J. Chadbourn rev. 1981) (defining a "judicial admission or stipulation" as an "express waiver made . . . by the party or his attorney conceding for the purposes of the trial the truth of some alleged fact" (emphasis deleted)); Christian Legal Soc. Chapter of Univ. of Cal., Hastings College of Law v. Martinez, 561 U. S. ___, ___ (2010) (slip op., at 10) (describing a stipulation as "`binding and conclusive'" and "`not subject to subsequent variation'" (quoting 83 C. J. S., Stipulations §93 (2000))); 9 Wigmore, supra, §2590, at 822 (the "vital feature" of a judicial admission is "universally conceded to be its conclusiveness upon the party making it"). The stipulation Knowles proffered to the District Court, however, does not speak for those he purports to represent.

That is because a plaintiff who files a proposed class action cannot legally bind members of the proposed class before the class is certified. See Smith v. Bayer Corp., 564 U. S. ___, ___ (2011) (slip op., at 15) ("Neither a proposed class action nor a rejected class action may bind nonparties"); id., at ___ (slip op., at 13) ("`[A] nonnamed class member is [not] a party to the class-action litigation before the class is certified'" (quoting Devlin v. Scardelletti, 536 U. S. 1, 16, n. 1 (2002) (SCALIA, J., dissenting))); Brief for Respondent 12 (conceding that "a damages limitation . . . cannot have a binding effect on the merits of absent class members' claims unless and until the class is certified").

Because his precertification stipulation does not bind anyone but himself, Knowles has not reduced the value of the putative class members' claims. For jurisdictional purposes, our inquiry is limited to examining the case "as of the time it was filed in state court," Wisconsin Dept. of Corrections v. Schacht, 524 U. S. 381, 390 (1998). At that point, Knowles lacked the authority to concede the amount-in-controversy issue for the absent class members. The Federal District Court, therefore, wrongly concluded that Knowles' precertification stipulation could overcome its finding that the CAFA jurisdictional threshold had been met.

Knowles concedes that "[f]ederal jurisdiction cannot be based on contingent future events." Brief for Respondent 20. Yet the two legal principles to which we have just referred—that stipulations must be binding and that a named plaintiff cannot bind precertification class members—mean that the amount to which Knowles has stipulated is in effect contingent.

If, for example, as Knowles' complaint asserts, "hundreds, and possibly thousands" of persons in Arkansas have similar claims, App. to Pet. for Cert. 66, and if each of those claims places a significant sum in controversy, the state court might certify the class and permit the case to proceed, but only on the condition that the stipulation be excised. Or a court might find that Knowles is an inadequate representative due to the artificial cap he purports to impose on the class' recovery. E.g., Back Doctors Ltd. v. Metropolitan Property & Cas. Ins. Co., 637 F. 3d 827, 830-831 (CA7 2011) (noting a class representative's fiduciary duty not to "throw away what could be a major component of the class's recovery"). Similarly, another class member could intervene with an amended complaint (without a stipulation), and the District Court might permit the action to proceed with a new representative. See 5 A. Conte & H. Newberg, Class Actions §16:7, p. 154 (4th ed. 2002) ("[M]embers of a class have a right to intervene if their interests are not adequately represented by existing parties"). Even were these possibilities remote in Knowles' own case, there is no reason to think them farfetched in other cases where similar stipulations could have more dramatic amount-lowering effects.

The strongest counterargument, we believe, takes a syllogistic form: First, this complaint contains a presently nonbinding stipulation that the class will seek damages that amount to less than $5 million. Second, if the state court eventually certifies that class, the stipulation will bind those who choose to remain as class members. Third, if the state court eventually insists upon modification of the stipulation (thereby permitting class members to obtain more than $5 million), it will have in effect created a new, different case. Fourth, CAFA, however, permits the federal court to consider only the complaint that the plaintiff has filed, i.e., this complaint, not a new, modified (or amended) complaint that might eventually emerge.

Our problem with this argument lies in its conclusion. We do not agree that CAFA forbids the federal court to consider, for purposes of determining the amount in controversy, the very real possibility that a nonbinding, amount-limiting, stipulation may not survive the class certification process. This potential outcome does not result in the creation of a new case not now before the federal court. To hold otherwise would, for CAFA jurisdictional purposes, treat a nonbinding stipulation as if it were binding, exalt form over substance, and run directly counter to CAFA's primary objective: ensuring "Federal court consideration of interstate cases of national importance." §2(b)(2), 119 Stat. 5. It would also have the effect of allowing the subdivision of a $100 million action into 21 just-below-$5-million state-court actions simply by including nonbinding stipulations; such an outcome would squarely conflict with the statute's objective.

We agree with Knowles that a federal district court might find it simpler to value the amount in controversy on the basis of a stipulation than to aggregate the value of the individual claims of all who meet the class description. We also agree that, when judges must decide jurisdictional matters, simplicity is a virtue. See Hertz Corp. v. Friend, 559 U. S. 77, 94 (2010). But to ignore a nonbinding stipulation does no more than require the federal judge to do what she must do in cases without a stipulation and what the statute requires, namely "aggregat[e]" the "claims of the individual class members." 28 U. S. C. §1332(d)(6).

Knowles also points out that federal courts permit individual plaintiffs, who are the masters of their complaints, to avoid removal to federal court, and to obtain a remand to state court, by stipulating to amounts at issue that fall below the federal jurisdictional requirement. That is so. See St. Paul Mercury Indemnity Co. v. Red Cab Co., 303 U. S. 283, 294 (1938) ("If [a plaintiff] does not desire to try his case in the federal court he may resort to the expedient of suing for less than the jurisdictional amount, and though he would be justly entitled to more, the defendant cannot remove"). But the key characteristic about those stipulations is that they are legally binding on all plaintiffs. See 14AA C. Wright, A. Miller, & E. Cooper, Federal Practice and Procedure §3702.1, p. 335 (4th ed. 2011) (federal court, as condition for remand, can insist on a "binding affidavit or stipulation that the plaintiff will continue to claim less than the jurisdictional amount" (emphasis added)). That essential feature is missing here, as Knowles cannot yet bind the absent class.

Knowles argues in the alternative that a stipulation is binding to the extent it limits attorney's fees so that the amount in controversy remains below the CAFA threshold. We do not consider this issue because Knowles' stipulation did not provide for that option.

In sum, the stipulation at issue here can tie Knowles' hands, but it does not resolve the amount-in-controversy question in light of his inability to bind the rest of the class. For this reason, we believe the District Court, when following the statute to aggregate the proposed class members' claims, should have ignored that stipulation. Because it did not, we vacate the judgment below and remand the case for further proceedings consistent with this opinion.

It is so ordered.

CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE NINTH CIRCUIT

[369] [369] Thomas, J., delivered the opinion of the Court, in which Rehnquist, C. J., and O'Connor, Scalia, Kennedy, Souter, and Breyer, JJ., joined, and in which Stevens, J., joined as to Parts I, II—A, and II—C. Stevens, J., filed an opinion concurring in part and dissenting in part, post, p. 387. Ginsburg, J., filed an opinion concurring in part and dissenting in part, in which Stevens, J., joined, and in which Souter, J., joined as to Part II—B, post, p. 388.

Barry R. Ostrager argued the cause for petitioners. With him on the briefs was Geoffrey C. Hazard, Jr.

Henry Paul Monaghan argued the cause for respondents. With him on the brief were Harold Edgar, Roger W. Kirby, and Irving Malchman.^[1]

Justice Thomas, delivered the opinion of the Court.

This case presents the question whether a federal court may withhold full faith and credit from a state-court judgment approving a class-action settlement simply because the settlement releases claims within the exclusive jurisdiction of the federal courts. The answer is no. Absent a partial repeal of the Full Faith and Credit Act, 28 U. S. C. § 1738, by another federal statute, a federal court must give the judgment the same effect that it would have in the courts of the State in which it was rendered.

I

In 1990, petitioner Matsushita Electric Industrial Co. made a tender offer for the common stock of MCA, Inc., a [370] Delaware corporation. The tender offer not only resulted in Matsushita's acquisition of MCA, but also precipitated two lawsuits on behalf of the holders of MCA's common stock. First, a class action was filed in the Delaware Court of Chancery against MCA and its directors for breach of fiduciary duty in failing to maximize shareholder value. The complaint was later amended to state additional claims against MCA's directors for, inter alia, waste of corporate assets by exposing MCA to liability under the federal securities laws. In addition, Matsushita was added as a defendant and was accused of conspiring with MCA's directors to violate Delaware law. The Delaware suit was based purely on statelaw claims.

While the state class action was pending, the instant suit was filed in Federal District Court in California. The complaint named Matsushita as a defendant and alleged that Matsushita's tender offer violated Securities and Exchange Commission (SEC) Rules 10b—13 and 14d—10.^[2] These Rules were created by the SEC pursuant to the 1968 Williams Act Amendments to the Securities Exchange Act of 1934 (Exchange Act), 48 Stat. 881, as amended, 15 U. S. C. § 78a et seq. Section 27 of the Exchange Act confers exclusive jurisdiction upon the federal courts for suits brought to enforce the Act or rules and regulations promulgated thereunder. See 15 U. S. C. § 78aa. The District Court declined to certify the class, entered summary judgment for Matsushita, and dismissed the case. The plaintiffs appealed to the Court of Appeals for the Ninth Circuit.

After the federal plaintiffs filed their notice of appeal but before the Ninth Circuit handed down a decision, the parties [371] to the Delaware suit negotiated a settlement.^[3] In exchange for a global release of all claims arising out of the Matsushita-MCA acquisition, the defendants would deposit $2 million into a settlement fund to be distributed pro rata to the members of the class. As required by Delaware Chancery Rule 23, which is modeled on Federal Rule of Civil Procedure 23, the Chancery Court certified the class for purposes of settlement and approved a notice of the proposed settlement. The notice informed the class members of their right to request exclusion from the settlement class and to appear and present argument at a scheduled hearing to determine the fairness of the settlement. In particular, the notice stated that "[b]y filing a valid Request for Exclusion, a member of the Settlement Class will not be precluded by the Settlement from individually seeking to pursue the claims alleged in the . . . California Federal Actions, . . . or any other claim relating to the events at issue in the Delaware Actions." App. to Pet. for Cert. 96a. Two such notices were mailed to the class members and the notice was also published in the national edition of the Wall Street Journal. The Chancery Court then held a hearing. After argument from several objectors, the court found the class representation adequate and the settlement fair.

The order and final judgment of the Chancery Court incorporated the terms of the settlement agreement, providing:

"All claims, rights and causes of action (state or federal, including but not limited to claims arising under the federal securities law, any rules or regulations promulgated thereunder, or otherwise), whether known or unknown that are, could have been or might in the future be asserted by any of the plaintiffs or any member of the Settlement Class (other than those who have val-

[372] idly requested exclusion therefrom), . . . in connection with or that arise now or hereafter out of the Merger Agreement, the Tender Offer, the Distribution Agreement, the Capital Contribution Agreement, the employee compensation arrangements, the Tender Agreements, the Initial Proposed Settlement, this Settlement. . . and including without limitation the claims as- serted in the California Federal Actions . . . are hereby compromised, settled, released and discharged with prejudice by virtue of the proceedings herein and this Order and Final Judgment." In re MCA, Inc. Share- holders Litigation, C. A. No. 11740 (Feb. 22, 1993), reprinted in App. to Pet. for Cert. 74a—75a (emphasis added). The judgment also stated that the notice met all the requirements of due process. The Delaware Supreme Court affirmed. In re MCA, Inc., Shareholders Litigation, 633 A. 2d 370 (1993) (judgt. order).

Respondents were members of both the state and federal plaintiff classes. Following issuance of the notice of proposed settlement of the Delaware litigation, respondents neither opted out of the settlement class nor appeared at the hearing to contest the settlement or the representation of the class. On appeal in the Ninth Circuit, petitioner Matsushita invoked the Delaware judgment as a bar to further prosecution of that action under the Full Faith and Credit Act, 28 U. S. C. § 1738.

The Ninth Circuit rejected petitioner's argument, ruling that § 1738 did not apply. Epstein v. MCA, Inc., 50 F. 3d 644, 661-666 (1995). Instead, the Court of Appeals fashioned a test under which the preclusive force of a state-court settlement judgment is limited to those claims that "could. . . have been extinguished by the issue preclusive effect of an adjudication of the state claims." Id., at 665. The lower courts have taken varying approaches to determining the preclusive effect of a state-court judgment, entered in a class [373] or derivative action, that provides for the release of exclusively federal claims.^[4] We granted certiorari to clarify this important area of federal law. 515 U. S. 1187 (1995).

II

The Full Faith and Credit Act mandates that the "judicial proceedings" of any State "shall have the same full faith and credit in every court within the United States .. . as they have by law or usage in the courts of such State . . . from which they are taken." 28 U. S. C. § 1738. The Act thus directs all courts to treat a state-court judgment with the same respect that it would receive in the courts of the rendering State. Federal courts may not "employ their own rules . . . in determining the effect of state judgments," but must "accept the rules chosen by the State from which the judgment is taken." Kremer v. Chemical Constr. Corp., 456 U. S. 461, 481-482 (1982). Because the Court of Appeals failed to follow the dictates of the Act, we reverse.

A

The state-court judgment in this case differs in two respects from the judgments that we have previously considered in our cases under the Full Faith and Credit Act. As respondents and the Court of Appeals stressed, the judgment was the product of a class action and incorporated a settlement agreement releasing claims within the exclusive jurisdiction of the federal courts. Though respondents urge "the irrelevance of section 1738 to this litigation," Brief for Respondents 25, we do not think that either of these features exempts the judgment from the operation of § 1738.

That the judgment at issue is the result of a class action, rather than a suit brought by an individual, does not undermine [374] the initial applicability of § 1738. The judgment of a state court in a class action is plainly the product of a "judicial proceeding" within the meaning of § 1738. Cf. McDonald v. West Branch, 466 U. S. 284, 287-288 (1984) (holding that § 1738 does not apply to arbitration awards because arbitration is not a "judicial proceeding"). Therefore, a judgment entered in a class action, like any other judgment entered in a state judicial proceeding, is presumptively entitled to full faith and credit under the express terms of the Act.

Further, § 1738 is not irrelevant simply because the judgment in question might work to bar the litigation of exclusively federal claims. Our decision in Marrese v. American Academy of Orthopaedic Surgeons, 470 U. S. 373 (1985), made clear that where § 1738 is raised as a defense in a subsequent suit, the fact that an allegedly precluded "claim is within the exclusive jurisdiction of the federal courts does not necessarily make § 1738 inapplicable. " Id., at 380 (emphasis added). In so holding, we relied primarily on Kremer v. Chemical Constr. Corp., supra, which held, without deciding whether claims under Title VII of the Civil Rights Act of 1964 are exclusively federal, that state-court proceedings may be issue preclusive in Title VII suits in federal court. Kremer, we said, "implies that absent an exception to § 1738, state law determines at least the . . . preclusive effect of a prior state judgment in a subsequent action involving a claim within the exclusive jurisdiction of the federal courts." Marrese, 470 U. S., at 381. Accordingly, we decided that "a state court judgment may in some circumstances have preclusive effect in a subsequent action within the exclusive jurisdiction of the federal courts." Id., at 380.

In Marrese, we discussed Nash County Bd. of Ed. v. Biltmore Co., 640 F. 2d 484 (CA4), cert. denied, 454 U. S. 878 (1981), a case that concerned a state-court settlement judgment. In Nash, the question was whether the judgment, which approved the settlement of state antitrust claims, prevented the litigation of exclusively federal antitrust claims. [375] See 470 U. S., at 382, n. 2. We suggested that the approach outlined in Marrese would also apply in cases like Nash that involve judgments upon settlement: that is, § 1738 would control at the outset. See 470 U. S., at 382, n. 2. In accord with these precedents, we conclude that § 1738 is generally applicable in cases in which the state-court judgment at issue incorporates a class-action settlement releasing claims solely within the jurisdiction of the federal courts.

B

Marrese provides the analytical framework for deciding whether the Delaware court's judgment precludes this exclusively federal action. When faced with a state-court judgment relating to an exclusively federal claim, a federal court must first look to the law of the rendering State to ascertain the effect of the judgment. See id., at 381-382. If state law indicates that the particular claim or issue would be barred from litigation in a court of that State, then the federal court must next decide whether, "as an exception to § 1738," it "should refuse to give preclusive effect to [the] state court judgment." Id., at 383. See also Migra v. Warren City School Dist. Bd. of Ed., 465 U. S. 75, 81 (1984) ("[I]n the absence of federal law modifying the operation of § 1738, the preclusive effect in federal court of [a] state-court judgment is determined by [state] law").

1

We observed in Marrese that the inquiry into state law would not always yield a direct answer. Usually, "a state court will not have occasion to address the specific question whether a state judgment has issue or claim preclusive effect in a later action that can be brought only in federal court." 470 U. S., at 381-382. Where a judicially approved settlement is under consideration, a federal court may consequently find guidance from general state law on the preclusive force of settlement judgments. See, e. g., id., at [376] 382-383, n. 2 (observing in connection with Nash that "[North Carolina] law gives preclusive effect to consent judgment[s]"). Here, in addition to providing rules regarding the preclusive force of class-action settlement judgments in subsequent suits in state court, the Delaware courts have also spoken to the particular effect of such judgments in federal court.

Delaware has traditionally treated the impact of settlement judgments on subsequent litigation in state court as a question of claim preclusion. Early cases suggested that Delaware courts would not afford claim preclusive effect to a settlement releasing claims that could not have been presented in the trial court. See Ezzes v. Ackerman, 234 A. 2d 444, 445-446 (Del. 1967) ("[A] judgment entered either after trial on the merits or upon an approved settlement is res judicata and bars subsequent suit on the same claim . . .. [T]he defense of res judicata . . . is available if the pleadings framing the issues in the first action would have permitted the raising of the issue sought to be raised in the second action, and if the facts were known, or could have been known to the plaintiff in the second action at the time of the first action"). As the Court of Chancery has perceived, however, "the Ezzes inquiry [was] modified in regard to class actions," In re Union Square Associates Securities Litigation, C. A. No. 11028, 1993 WL 220528, *3 (June 16, 1993), by the Delaware Supreme Court's decision in Nottingham Partners v. Dana, 564 A. 2d 1089 (1989).

In Nottingham, a class action, the Delaware Supreme Court approved a settlement that released claims then pending in federal court. In approving that settlement, the Nottingham court appears to have eliminated the Ezzes requirement that the claims could have been raised in the suit that produced the settlement, at least with respect to class actions:

"`[I]n order to achieve a comprehensive settlement that would prevent relitigation of settled questions at the [377] core of a class action, a court may permit the release of a claim based on the identical factual predicate as that underlying the claims in the settled class action even though the claim was not presented and might not have been presentable in the class action.' " 564 A. 2d, at 1106 (quoting TBK Partners, Ltd. v. Western Union Corp., 675 F. 2d 456, 460 (CA2 1982)).

See Union Square, supra, at *3 (relying directly on Nottingham to hold that a Delaware court judgment settling a class action was res judicata and barred arbitration of duplicative claims that could not have been brought in the first suit). These cases indicate that even if, as here, a claim could not have been raised in the court that rendered the settlement judgment in a class action, a Delaware court would still find that the judgment bars subsequent pursuit of the claim.

The Delaware Supreme Court has further manifested its understanding that when the Court of Chancery approves a global release of claims, its settlement judgment should preclude ongoing or future federal-court litigation of any released claims. In Nottingham, the Court stated that "[t]he validity of executing a general release in conjunction with the termination of litigation has long been recognized by the Delaware courts. More specifically, the Court of Chancery has a history of approving settlements that have implicitly or explicitly included a general release, which would also release federal claims." 564 A. 2d, at 1105 (citation omitted). Though the Delaware Supreme Court correctly recognized in Nottingham that it lacked actual authority to order the dismissal of any case pending in federal court, it asserted that state-court approval of the settlement would have the collateral effect of preventing class members from prosecuting their claims in federal court. Perhaps the clearest statement of the Delaware Chancery Court's view on this matter was articulated in the suit preceding this one: "When a state court settlement of a class action releases all claims which arise out of the challenged transaction and is determined to [378] be fair and to have met all due process requirements, the class members are bound by the release or the doctrine of issue preclusion. Class members cannot subsequently relitigate the claims barred by the settlement in a federal court." In re MCA, Inc. Shareholders Litigation, 598 A. 2d 687, 691 (1991).^[5] We are aware of no Delaware case that suggests otherwise.

Given these statements of Delaware law, we think that a Delaware court would afford preclusive effect to the settlement judgment in this case, notwithstanding the fact that respondents could not have pressed their Exchange Act claims in the Court of Chancery. The claims are clearly within the scope of the release in the judgment, since the judgment specifically refers to this lawsuit. As required by Delaware Court of Chancery Rule 23, see Prezant v. De Angelis, 636 A. 2d 915, 920 (1994), the Court of Chancery found, and the Delaware Supreme Court affirmed, that the settlement was "fair, reasonable and adequate and in the best interests of the . . . Settlement class" and that notice to the class was "in full compliance with . . . the requirements of due process." In re MCA, Inc. Shareholders Litigation, C. A. No. 11740 (Feb. 22, 1993), reprinted in App. to Pet. for Cert. 73a, 74a. Cf. Phillips Petroleum Co. v. Shutts, 472 U. S. 797, 812 (1985) (due process for class-action plaintiffs requires "notice plus an opportunity to be heard and participate in the litigation"). The Court of Chancery "further determined that the plaintiffs[,] . . . as representatives of the Settlement Class, have fairly and adequately protected the [379] interests of the Settlement Class." In re MCA, Inc. Shareholders Litigation, supra, reprinted in App. to Pet. for Cert. 73a. Cf. Phillips Petroleum Co., supra, at 812 (due process requires that "the named plaintiff at all times adequately represent the interests of the absent class members").^[6] Under Delaware Rule 23, as under Federal Rule of Civil Procedure 23, "[a]ll members of the class, whether of a plaintiff or a defendant class, are bound by the judgment entered in the action unless, in a Rule 23(b)(3) action, they make a timely election for exclusion." 2 H. Newberg, Class Actions § 2755, p. 1224 (1977). See also Cooper v. Federal Reserve Bank of Richmond, 467 U. S. 867, 874 (1984) ("There is of course no dispute that under elementary principles of prior adjudication a judgment in a properly entertained class action is binding on class members in any subsequent litigation"). Respondents do not deny that, as shareholders of MCA's common stock, they were part of the plaintiff class and that they never opted out; they are bound, then, by the judgment.^[7]

[380] 2

Because it appears that the settlement judgment would be res judicata under Delaware law, we proceed to the second step of the Marrese analysis and ask whether § 27 of the Exchange Act, which confers exclusive jurisdiction upon the federal courts for suits arising under the Act, partially repealed § 1738. Section 27 contains no express language regarding its relationship with § 1738 or the preclusive effect of related state-court proceedings. Thus, any modification of § 1738 by § 27 must be implied. In deciding whether § 27 impliedly created an exception to § 1738, the "general question is whether the concerns underlying a particular grant of exclusive jurisdiction justify a finding of an implied partial repeal of § 1738." Marrese, 470 U. S., at 386. "Resolution of this question will depend on the particular federal statute as well as the nature of the claim or issue involved in the subsequent federal action. . . . [T]he primary consideration must be the intent of Congress." Ibid.

As a historical matter, we have seldom, if ever, held that a federal statute impliedly repealed § 1738. See Parsons Steel, Inc. v. First Alabama Bank, 474 U. S. 518, 523-525 (1986) (Anti-Injunction Act does not limit § 1738); Migra v. Warren City School Dist. Bd. of Ed., 465 U. S., at 83-85 (42 U. S. C. § 1983 does not limit claim preclusion under § 1738); Kremer v. Chemical Constr. Corp., 456 U. S., at 468-476 (Title VII of the Civil Rights Act of 1964 does not limit § 1738); Allen v. McCurry, 449 U. S. 90, 96-105 (1980) (§ 1983 does not limit issue preclusion under § 1738). But cf. Brown v. Felsen, 442 U. S. 127, 138-139 (1979) (declining to give claim preclusive [381] effect to prior state-court debt collection proceeding in federal bankruptcy suit, without discussing § 1738, state law, or implied repeals). The rarity with which we have discovered implied repeals is due to the relatively stringent standard for such findings, namely, that there be an "`irreconcilable conflict' " between the two federal statutes at issue. Kremer v. Chemical Constr. Corp., supra, at 468 (quoting Radzanower v. Touche Ross & Co., 426 U. S. 148, 154 (1976)).

Section 27 provides that "[t]he district courts of the United States . . . shall have exclusive jurisdiction . . . of all suits in equity and actions at law brought to enforce any liability or duty created by this chapter or the rules and regulations thereunder." 15 U. S. C. § 78aa. There is no suggestion in § 27 that Congress meant for plaintiffs with Exchange Act claims to have more than one day in court to challenge the legality of a securities transaction. Though the statute plainly mandates that suits alleging violations of the Exchange Act may be maintained only in federal court, nothing in the language of § 27 "remotely expresses any congressional intent to contravene the common-law rules of preclusion or to repeal the express statutory requirements of . . . 28 U. S. C. § 1738." Allen v. McCurry, supra, at 97-98.

Nor does § 27 evince any intent to prevent litigants in state court—whether suing as individuals or as part of a class— from voluntarily releasing Exchange Act claims in judicially approved settlements. While § 27 prohibits state courts from adjudicating claims arising under the Exchange Act, it does not prohibit state courts from approving the release of Exchange Act claims in the settlement of suits over which they have properly exercised jurisdiction, i. e., suits arising under state law or under federal law for which there is concurrent jurisdiction. In this case, for example, the Delaware action was not "brought to enforce" any rights or obligations under the Act. The Delaware court asserted judicial power [382] over a complaint asserting purely state-law causes of action^[8] and, after the parties agreed to settle, certified the class and approved the settlement pursuant to the requirements of Delaware Rule of Chancery 23 and the Due Process Clause. Thus, the Delaware court never trespassed upon the exclusive territory of the federal courts, but merely approved the settlement of a common-law suit pursuant to state and nonexclusive federal law. See Abramson v. Pennwood Investment Corp., 392 F. 2d 759, 762 (CA2 1968) ("Although the state court could not adjudicate the federal claim, it was within its powers over the corporation and the parties to approve the release of that claim as a condition of settlement of the state action"). While it is true that the state court assessed the general worth of the federal claims in determining the fairness of the settlement, such assessment does not amount to a judgment on the merits of the claims. See TBK Partners, Ltd. v. Western Union Corp., 675 F. 2d 456, 461 (CA2 1982) ("`Approval of a settlement does not call for findings of fact regarding the claims to be compromised. The court is concerned only with the likelihood of success or failure; the actual merits of the controversy are not to be determined' ") (quoting Haudek, The Settlement and Dismissal of Stockholders' Actions-Part II: The Settlement, 23 Sw. L. J. 765, 809 (1969) (footnotes omitted)). The Delaware court never purported to resolve the merits of the Exchange Act claims in the course of appraising the settlement; indeed, it expressly disavowed that purpose. See In re MCA, Inc. Shareholders Litigation, C. A. No. 11740 (Feb. 16, 1993), reprinted in App. to Pet. for Cert. 68a ("In determining whether a settlement should be approved, a court should not try the merits of the underlying claims. This principle would seem to be especially appropriate where the underlying [383] claims, like the federal claims here, are outside the jurisdiction of this Court" (citation omitted)).

The legislative history of the Exchange Act elucidates no specific purpose on the part of Congress in enacting § 27. See Murphy v. Gallagher, 761 F. 2d 878, 885 (CA2 1985) (noting that the legislative history of the Exchange Act provides no readily apparent explanation for the provision of exclusive jurisdiction in § 27) (citing 2 & 3 L. Loss, Securities Regulation 997, 2005 (2d ed. 1961)). We may presume, however, that Congress intended § 27 to serve at least the general purposes underlying most grants of exclusive jurisdiction: "to achieve greater uniformity of construction and more effective and expert application of that law." Murphy v. Gallagher, supra, at 885. When a state court upholds a settlement that releases claims under the Exchange Act, it threatens neither of these policies. There is no danger that state-court judges who are not fully expert in federal securities law will say definitively what the Exchange Act means and enforce legal liabilities and duties thereunder. And the uniform construction of the Act is unaffected by a state court's approval of a proposed settlement because the state court does not adjudicate the Exchange Act claims but only evaluates the overall fairness of the settlement, generally by applying its own business judgment to the facts of the case. See, e. g., Polk v. Good, 507 A. 2d 531, 535 (Del. 1986).

Furthermore, other provisions of the Exchange Act suggest that Congress did not intend to create an exception to § 1738 for suits alleging violations of the Act. Congress plainly contemplated the possibility of dual litigation in state and federal courts relating to securities transactions. See 15 U. S. C. § 78bb(a) (preserving "all other rights and remedies that may exist at law or in equity"). And all that Congress chose to say about the consequences of such litigation is that plaintiffs ought not obtain double recovery. See ibid. Congress said nothing to modify the background rule that where a state-court judgment precedes that of a federal [384] court, the federal court must give full faith and credit to the state-court judgment. See Murphy v. Gallagher, supra, at 884.

Finally, precedent supports the conclusion that the concerns underlying the grant of exclusive jurisdiction in § 27 are not undermined by state-court approval of settlements releasing Exchange Act claims. We have held that statecourt proceedings may, in various ways, subsequently affect the litigation of exclusively federal claims without running afoul of the federal jurisdictional grant in question. In Becher v. Contoure Laboratories, Inc., 279 U. S. 388 (1929) (cited in Marrese, 470 U. S., at 381), we held that state-court findings of fact were issue preclusive in federal patent suits. We did so with full recognition that "the logical conclusion from the establishing of [the state law] claim is that Becher's patent is void." 279 U. S., at 391. Becher reasoned that although "decrees validating or invalidating patents belong to the Courts of the United States," that "does not give sacrosanctity to facts that may be conclusive upon the question in issue." Ibid. Similarly, while binding legal determinations of rights and liabilities under the Exchange Act are for federal courts only, there is nothing sacred about the approval of settlements of suits arising under state law, even where the parties agree to release exclusively federal claims. See also Brown v. Felsen, 442 U. S., at 139, n. 10 (noting that "[i]f, in the course of adjudicating a state-law question, a state court should determine factual issues using standards identical to those of § 17, then collateral estoppel, in the absence of countervailing statutory policy, would bar relitigation of those issues in the bankruptcy court"); Pratt v. Paris Gas Light & Coke Co., 168 U. S. 255, 258 (1897) (when a state court has jurisdiction of the parties and the subject matter of the complaint, the state court may decide the validity of a patent when that issue is raised as a defense).

We have also held that Exchange Act claims may be resolved by arbitration rather than litigation in federal court. [385] In Shearson/American Express Inc. v. McMahon, 482 U. S. 220 (1987), we found that parties to an arbitration agreement could waive the right to have their Exchange Act claims tried in federal court and agree to arbitrate the claims. Id. , at 227-228. It follows that state-court litigants ought also to be able to waive, or "release," the right to litigate Exchange Act claims in a federal forum as part of a settlement agreement. As Shearson/American Express Inc. demonstrates, a statute conferring exclusive federal jurisdiction for a certain class of claims does not necessarily require resolution of those claims in a federal court.

Taken together, these cases stand for the general proposition that even when exclusively federal claims are at stake, there is no "universal right to litigate a federal claim in a federal district court." Allen v. McCurry, 449 U. S., at 105. If class-action plaintiffs wish to preserve absolutely their right to litigate exclusively federal claims in federal court, they should either opt out of the settlement class or object to the release of any exclusively federal claims. In fact, some of the plaintiffs in the Delaware class action requested exclusion from the settlement class. They are now proceeding in federal court with their federal claims, unimpeded by the Delaware judgment.

In the end, §§ 27 and 1738 "do not pose an either-or proposition." Connecticut Nat. Bank v. Germain, 503 U. S. 249, 253 (1992). They can be reconciled by reading § 1738 to mandate full faith and credit of state-court judgments incorporating global settlements, provided the rendering court had jurisdiction over the underlying suit itself, and by reading § 27 to prohibit state courts from exercising jurisdiction over suits arising under the Exchange Act. Cf. 18 C. Wright, A. Miller, & E. Cooper, Federal Practice and Procedure § 4470, pp. 688-689 (1981) ("[S]ettlement of state court litigation has been held to defeat a subsequent federal action if the settlement was intended to apply to claims in exclusive federal jurisdiction as well as other claims. . . . These rulings [386] are surely correct"). Congress' intent to provide an exclusive federal forum for adjudication of suits to enforce the Exchange Act is clear enough. But we can find no suggestion in § 27 that Congress meant to override the "principles of comity and repose embodied in § 1738," Kremer v. Chemical Constr. Corp., 456 U. S., at 463, by allowing plaintiffs with Exchange Act claims to release those claims in state court and then litigate them in federal court. We conclude that the Delaware courts would give the settlement judgment preclusive effect in a subsequent proceeding and, further, that § 27 did not effect a partial repeal of § 1738.

C

The Court of Appeals did not engage in any analysis of Delaware law pursuant to § 1738. Rather, the Court of Appeals declined to apply § 1738 on the ground that where the rendering forum lacked jurisdiction over the subject matter or the parties, full faith and credit is not required. 50 F. 3d, at 661, 666. See Underwriters Nat. Assurance Co. v. North Carolina Life & Accident & Health Ins. Guaranty Assn., 455 U. S. 691, 704-705 (1982) ("`[A] judgment of a court in one State is conclusive upon the merits in a court in another State only if the court in the first State had power to pass on the merits—had jurisdiction, that is, to render the judgment' ") (quoting Durfee v. Duke, 375 U. S. 106, 110 (1963)). The Court of Appeals decided that the subject-matter jurisdiction exception to full faith and credit applies to this case because the Delaware court acted outside the bounds of its own jurisdiction in approving the settlement, since the settlement released exclusively federal claims. See 50 F. 3d, at 661-662, and n. 25.

As explained above, the state court in this case clearly possessed jurisdiction over the subject matter of the underlying suit and over the defendants. Only if this were not so—for instance, if the complaint alleged violations of the Exchange Act and the Delaware court rendered a judgment [387] on the merits of those claims—would the exception to § 1738 for lack of subject-matter jurisdiction apply. Where, as here, the rendering court in fact had subject-matter jurisdiction, the subject-matter-jurisdiction exception to full faith and credit is simply inapposite. In such a case, the relevance of a federal statute that provides for exclusive federal jurisdiction is not to the state court's possession of jurisdiction per se, but to the existence of a partial repeal of § 1738.^[9]

* * *

The judgment of the Court of Appeals is reversed, and the case is remanded for proceedings consistent with this opinion.

It is so ordered.

Justice Stevens, concurring in part and dissenting in part.

While I join Parts I, II—A, and II—C of the Court's opinion, and while I also agree with the Court's reasons for concluding that § 27 of the Securities Exchange Act of 1934 does not create an implied partial repeal of the Full Faith and Credit Act, I join neither Part II—B nor the Court's judgment because I agree with Justice Ginsburg that the question of Delaware law should be addressed by the Court of Appeals in the first instance, and that the Ninth Circuit remains free to consider whether Delaware courts fully and fairly litigated the adequacy of class representation.

[388] Justice Ginsburg, with whom Justice Stevens joins, and with whom Justice Souter joins as to Part II—B, concurring in part and dissenting in part.

I join the Court's judgment to the extent that it remands the case to the Ninth Circuit. I agree that a remand is in order because the Court of Appeals did not attend to this Court's reading of 28 U. S. C. § 1738 in a controlling decision, Kremer v. Chemical Constr. Corp., 456 U. S. 461 (1982). But I would not endeavor, as the Court does, to speak the first word on the content of Delaware preclusion law. Instead, I would follow our standard practice of remitting that issue for decision, in the first instance, by the lower federal courts. See, e. g., Marrese v. American Academy of Orthopaedic Surgeons, 470 U. S. 373, 387 (1985).

I write separately to emphasize a point key to the application of § 1738: A state-court judgment generally is not entitled to full faith and credit unless it satisfies the requirements of the Fourteenth Amendment's Due Process Clause. See Kremer, 456 U. S., at 482-483. In the class-action setting, adequate representation is among the due process ingredients that must be supplied if the judgment is to bind absent class members. See Phillips Petroleum Co. v. Shutts, 472 U. S. 797, 808, 812 (1985); Prezant v. De Angelis, 636 A. 2d 915, 923-924 (Del. 1994).

Suitors in this action (called the "Epstein plaintiffs" in this opinion), respondents here, argued before the Ninth Circuit, and again before this Court, that they cannot be bound by the Delaware settlement because they were not adequately represented by the Delaware class representatives. They contend that the Delaware representatives' willingness to release federal securities claims within the exclusive jurisdiction of the federal courts for a meager return to the class members, but a solid fee to the Delaware class attorneys, disserved the interests of the class, particularly, the absentees. The inadequacy of representation was apparent, the Epstein plaintiffs maintained, for at the time of the settlement, [389] the federal claims were sub judice in the proper forum for those claims—the federal judiciary. Although the Ninth Circuit decided the case without reaching the due process check on the full faith and credit obligation, that inquiry remains open for consideration on remand. See ante, at 379, n. 5 (due process "w[as] not the basis for the decision below," so the Court "need not address [it]").

I

Matsushita's acquisition of MCA prompted litigation in state and federal courts. A brief account of that litigation will facilitate comprehension of the Epstein plaintiffs' position. On September 26, 1990, in response to reports in the financial press that Matsushita was negotiating to buy MCA, a suit was filed in the Court of Chancery of Delaware, a purported class action on behalf of the stockholders of MCA. Naming MCA and its directors (but not Matsushita) as defendants, the complaint invoked state law only. It alleged that MCA's directors had failed to carry out a market check to maximize shareholder value upon a change in corporate control, a check required by Revlon, Inc. v. MacAndrews & Forbes Holdings, Inc., 506 A. 2d 173, 182 (Del. 1986). For this alleged breach of fiduciary duty, the complaint sought, inter alia, an injunction against Matsushita's proposed acquisition of MCA.

Matsushita announced its tender offer on November 26, 1990. It offered holders of MCA common stock $71 per share, if they tendered their shares before December 29, 1990. The owners of 91% of MCA's common stock tendered their shares and, on January 3, 1991, for a price of $6.1 billion, Matsushita acquired MCA.

On December 3, 1990, a few days after the required Securities and Exchange Commission (SEC) filings disclosed the terms of the tender offer, several MCA shareholders filed suit in the United States District Court for the Central District [390] of California.^[10] Based solely on federal law, their complaints alleged that Matsushita, first named defendant, violated SEC Rules 14d—10, 17 CFR § 240.14d—10 (1994), and 10b—13, id., § 240.10b—13, by offering preferential treatment in the tender offer to MCA principals Lew Wasserman and Sidney Sheinberg. As stated in the complaint, the public tender offer included a special tax-driven stock swap arrangement for Wasserman, then MCA's chairman and chief executive officer, and a $21 million bonus for Sheinberg, then MCA's chief operating officer and owner of 1,170,000 shares of MCA common stock. These arrangements allegedly violated, inter alia, the SEC's "all-holder best-price" rule (Rule 14d—10), which requires bidders to treat all shareholders on equal terms. The claims of federal securities law violations fell within the exclusive jurisdiction of the federal court. See 15 U. S. C. § 78aa. The Epstein plaintiffs also sought class certification to represent all MCA shareholders at the time of the tender offer.

Two days later, counsel in the Delaware action advised MCA's counsel that the Delaware plaintiffs intended to amend their complaint to include additional claims against MCA and its directors and to add Matsushita as a defendant. The additional claims alleged that MCA wasted corporate assets by increasing the corporation's exposure to liability for violation of Rules 10b—13 and 14d—10, that MCA failed to [391] make full disclosure of the benefits MCA insiders would receive from the takeover, and that directors Wasserman and Sheinberg breached their fiduciary duties by negotiating preferential deals with Matsushita. Matsushita, the amended complaint alleged, had conspired with and aided and abetted MCA directors in violation of Delaware law.

Within days, the Delaware parties agreed to a settlement and, on December 17, 1990, submitted their proposal to the Delaware Vice Chancellor. The agreement provided for a modification of a "poison pill" in the corporate charter of an MCA subsidiary,^[11] and for a fees payment of $1 million to the class counsel. The settlement agreement required the release of all claims, state and federal, arising out of the tender offer.

The Vice Chancellor rejected the settlement agreement on April 22, 1991, for two reasons: the absence of any monetary benefit to the class members; and the potential value of the federal claims that the agreement proposed to release. The "generous payment" of $1 million in counsel fees, the Vice Chancellor observed, "confer[red] no benefit on the members of the Class." In re MCA, Inc. Shareholders Litigation, 598 A. 2d 687, 695 (Del. Ch. 1991). And the value of the revised poison pill to the class, the Vice Chancellor said, was "illusionary[,] . . . apparently . . . proposed merely to justify a settlement which offers no real monetary benefit to the Class." Id. , at 696. The Vice Chancellor described the state-law claims as "at best, extremely weak and, therefore, [of] little or no value." Id. , at 694. "[T]he only claims which have any substantial merit," he said, "are the claims. . . in the California federal suit that were not asserted in this Delaware action." Id. , at 696. After the rejection of [392] the settlement, the Delaware lawsuit lay dormant for more than a year.

The federal litigation proceeded. In various rulings, the District Court denied the federal plaintiffs' motion for partial summary judgment, denied the Epstein plaintiffs' motion for class certification, and granted Matsushita's motion for summary judgment dismissing the claims. On April 15, 1992, the District Court entered its final judgment, which the Epstein plaintiffs appealed to the Ninth Circuit.

On October 22, 1992, after the federal plaintiffs had filed their notice of appeal, the Delaware parties reached a second settlement agreement. Matsushita agreed to create a $2 million settlement fund that would afford shareholders 2 to 3 cents per share before payment of fees and costs. The Delaware class counsel requested $691,000 in fees. In return for this relief, the Delaware plaintiffs agreed to release "all claims, rights and causes of action (state or federal, including but not limited to claims arising under the federal securities laws, and any rules or regulations promulgated thereunder, or otherwise) . . . in connection with or that arise now or hereafter out of the [tender offer] . . . including without limitation the claims asserted in the California Federal Actions . . . ." App. 187-188. Unlike the first settlement proposal, the second agreement included an opt-out provision.

This time the Vice Chancellor approved the settlement. He stated: "[I]t is in the best interests of the class to settle this litigation and the terms of the settlement are fair and reasonable—although the value of the benefit to the class is meager." In re MCA, Inc. Shareholders Litigation, C. A. No. 11740, 1993 WL 43024, *1 (Del. Ch., Feb. 16, 1993). He found the class members' recovery of 2 to 3 cents per share "adequate (if only barely so) to support the proposed settlement." Id. , at *4. The federal claims, he reasoned, having been dismissed by the District Court, "now have minimal economic value." Ibid. And he gave weight to the presence [393] in the second settlement agreement of an opt-out provision. Ibid.

Addressing the objectors' contention that the proposed settlement was "collusive," the Vice Chancellor recalled that "the settling parties ha[d] previously proposed a patently inadequate settlement," and he agreed that "suspicions abound." Id. , at *5. Nevertheless, he noted, the "[o]bjectors have offered no evidence of any collusion," so he declined to reject the settlement on that ground. Ibid. Reducing the counsel fees from the requested $691,000 to $250,000, the Vice Chancellor offered this observation: "[T]he defendants' willingness to create the settlement fund seems likely to have been motivated as much by their concern as to their potential liability under the federal claims as by their concern for liability under the state law claims which this Court characterized as `extremely weak.' " Id. , at *6. In a brief order, the Delaware Supreme Court affirmed "on the basis of and for the reasons assigned by the Court of Chancery . . . ." In re MCA, Inc. Shareholders Litigation, C. A. No. 126,1993, 1993 WL 385041, *1 (Sept. 21, 1993), judgt. order reported at 633 A. 2d 370.

Before the Ninth Circuit, Matsushita argued that the Delaware class-action settlement barred litigation of the federal claims raised in the Epstein action. The Ninth Circuit disagreed. Relying on Federal Circuit Court decisions,^[12] the Court of Appeals held that state courts lack plenary power to approve settlements that effectively extinguish exclusively federal claims. Only if federal and state claims rest on the "identical factual predicate," the Ninth Circuit concluded, could a state-court settlement subsume an exclusively federal claim. It was not enough, in the Ninth Circuit's view, that the discrete federal and state claims stem from the [394] "same transaction," the test Matsushita urged. 50 F. 3d, at 661-665. The federal securities claims did not turn on the same operative facts as the state claims pleaded in Delaware, the Ninth Circuit found; accordingly, the federal claims could not have been extinguished by the issue-preclusive effect of an adjudication of the state claims. This analysis led the Ninth Circuit to declare that the Delaware decree "exceed[ed] the jurisdiction of the state court and, therefore, is not entitled to full faith and credit." Id. , at 666.

On the merits, the Ninth Circuit held, first, that a private right of action could be maintained to redress Rule 14d—10 violations. Id. , at 652. The court next held that Matsushita violated Rule 14d—10 by paying Wasserman consideration not offered to other shareholders, id. , at 657; reversing the District Court's disposition of this matter, the Ninth Circuit held that plaintiffs were entitled to summary judgment on liability and remanded for a determination of damages, ibid. Regarding plaintiffs' claim that the $21 million payment to Sheinberg violated Rule 14d—10, the Ninth Circuit vacated the summary judgment for Matsushita and remanded for a determination whether the payment was in fact made to encourage Sheinberg to tender his shares. Id. , at 659.

II

A

Section 1738's full faith and credit instruction, as the Court indicates, requires the forum asked to recognize a judgment first to determine the preclusive effect the judgment would have in the rendering court. See Kremer, 456 U. S., at 466; Marrese, 470 U. S., at 381. Because the Ninth Circuit did not evaluate the preclusive effect of the Delaware judgment through the lens of that State's preclusion law, I would remand for that determination. See id., at 386-387; Migra v. Warren City School Dist. Bd. of Ed., 465 U. S. 75, 87 (1984) ("Prudence . . . dictates that it is the District Court, in the [395] first instance, not this Court, that should interpret Ohio preclusion law and apply it.").^[13]

B

Every State's law on the preclusiveness of judgments is pervasively affected by the supreme law of the land. To be valid in the rendition forum, and entitled to recognition nationally, a state court's judgment must measure up to the requirements of the Fourteenth Amendment's Due Process Clause. Kremer, 456 U. S., at 482-483. "A State may not grant preclusive effect in its own courts to a constitutionally infirm judgment, and other state and federal courts are not required to accord full faith and credit to such a judgment." Id. , at 482 (footnote omitted).

In Phillips Petroleum Co. v. Shutts, this Court listed minimal procedural due process requirements a class-action money judgment must meet if it is to bind absentees; those requirements include notice, an opportunity to be heard, a right to opt out, and adequate representation. 472 U. S., at 812. "[T]he Due Process Clause of course requires that the named plaintiff at all times adequately represent the interests of the absent class members." Ibid. (citing Hansberry v. Lee, 311 U. S. 32, 42-43, 45 (1940)). As the Shutts Court's phrase "at all times" indicates, the class representative's duty to represent absent class members adequately is a continuing one. 472 U. S., at 812; see also Gonzales v. Cassidy, 474 F. 2d 67, 75 (CA5 1973) (representative's failure to pursue an appeal rendered initially adequate class representation inadequate, so that judgment did not bind the class).

Although emphasizing the constitutional significance of the adequate representation requirement, this Court has recognized [396] the first line responsibility of the States themselves for assuring that the constitutional essentials are met. See Hansberry, 311 U. S., at 42.^[14] Final judgments, however, remain vulnerable to collateral attack for failure to satisfy the adequate representation requirement. See id. , at 40, 42; see also Restatement (Second) of Judgments §§ 42(d) and (e), Comments e and f, pp. 406, 410-412 (1982) (noting, inter alia, that judgment is not binding on purportedly represented person where, to the knowledge of the opposing party, the representative seeks to advance his own interest at the expense of the represented person); see also id. , § 41, Comment a, p. 394 (if § 42 circumstances exist, "the represented person may avoid being bound either by appearing in the action before rendition of the judgment or by attacking the judgment by subsequent proceedings"). (Emphasis added.) A court conducting an action cannot predetermine the res judicata effect of the judgment; that effect can be tested only in a subsequent action. See 7B C. Wright, A. Miller, & M. Kane, Federal Practice and Procedure § 1789, p. 245 (2d ed. 1986).

In Delaware, the constitutional due process requirement of adequate representation is embodied in Delaware Court of Chancery's Rule 23, a class-action rule modeled on its federal counterpart. Prezant, 636 A. 2d, at 923, 920. Delaware requires, as a prerequisite to class certification, that the named [397] plaintiffs "fairly and adequately protect the interests of the class." Del. Ch. Rule 23(a)(4). In Prezant, the Delaware Supreme Court considered whether adequate class representation was "a sine qua non for approval of a class action settlement," and concluded that it was. 636 A. 2d, at 920, 926. The state high court overturned a judgment and remanded a settlement because the Court of Chancery had failed to make an explicit finding of adequate representation. Id. , at 926.

The Delaware Supreme Court underscored that due process demands more than notice and an opportunity to opt out; adequate representation, too, that court emphasized, is an essential ingredient. Id. , at 924 (citing Phillips Petroleum Co. v. Shutts, 472 U. S., at 812). Notice, the Delaware Supreme Court reasoned, cannot substitute for the thorough examination and informed negotiation an adequate representative would pursue. Prezant, 636 A. 2d, at 924. The court also recognized that opt-out rights "are infrequently utilized and usually economically impracticable." Ibid.

The Vice Chancellor's evaluation of the merits of the settlement could not bridge the gap, the Delaware Supreme Court said, because an inadequate representative "taint[s]" the entire settlement process. Id., at 925.^[15] "[A]n adequate representative," the Delaware Supreme Court explained, "vigorously prosecuting an action without conflict and bargaining at arms-length, may present different facts and a [398] different settlement proposal to the court than would an inadequate representative." Ibid. Consequently, the Delaware Supreme Court held, "in every class action settlement, the Court of Chancery is required to make an explicit determination on the record of the propriety of the class action according to the requisites of Rule 23(a) and (b)." Ibid.

In the instant case, the Epstein plaintiffs challenge the preclusive effect of the Delaware settlement, arguing that the Vice Chancellor never in fact made the constitutionally required determination of adequate representation. See id. , at 923.^[16] They contend that the state court left unresolved key questions: notably, did the class representatives share substantial common interests with the absent class members, and did counsel in Delaware vigorously press the interests of the class in negotiating the settlement.^[17] In particular, the Epstein plaintiffs question whether the Delaware class representatives—who filed the state lawsuit on September 26, 1990, two months before the November 26 tender offer announcement—actually tendered shares in December, thereby enabling them to litigate a Rule 14d—10 claim in federal court. They also suggest that the Delaware representatives undervalued the federal claims—claims they could only settle, but never litigate, in a Delaware court. Finally, [399] the Epstein plaintiffs contend that the Vice Chancellor improperly shifted the burden of proof;^[18] he rejected the Delaware objectors' charges of "collusion" for want of evidence while acknowledging that "suspicions [of collusion] abound." In re MCA, Inc. Shareholders Litigation, 1993 WL 43024, at *5.^[19]

Mindful that this is a court of final review and not first view, I do not address the merits of the Epstein plaintiffs' contentions, or Matsushita's counterargument that the issue of adequate representation was resolved by full and fair litigation in the Delaware Court of Chancery.^[20] These arguments remain open for airing on remand. I stress, however, the centrality of the procedural due process protection of adequate representation in class-action lawsuits, emphatically including those resolved by settlement. See generally J. Coffee, Suspect Settlements in Securities Litigation, N. Y. L. J., March 28, 1991, p. 5, col. 1.

[1] Daniel J. Popeo and Richard A. Samp filed a brief for the Washington Legal Foundation et al. as amici curiaeurging reversal.

Thaddeus Holt filed a brief for C. L. Grimes as amicus curiae urging affirmance.

[2] We express no opinion in this case on the existence of a private cause of action under §§ 14(d)(6) and (7) of the Securities Exchange Act of 1934, 15 U. S. C. §§ 78n(d)(6) and (7),the statutory authority for Rule 14d—10.

[3] A previous settlement was rejected by the Court of Chancery as unfair to the class. See In re MCA, Inc. Shareholders Litigation, 598 A. 2d 687 (1991).

[4] Compare the decision below with Grimes v. Vitalink Communications Corp., 17 F. 3d 1553 (CA3), cert. denied, 513 U. S. 986 (1994); Nottingham Partners v. Trans-Lux Corp., 925 F. 2d 29 (CA1 1991); and Abramson v. Pennwood Investment Corp., 392 F. 2d 759 (CA2 1968).

[5] In fact, the Chancery Court rejected the first settlement, which contained no opt-out provision, as unfair to the class precisely because it believed that the settlement would preclude the class from pursuing their exclusively federal claims in federal court. See In re MCA, Inc. Shareholders Litigation, 598 A. 2d, at 692 ("[I]f this Court provides for the release of all the claims arising out of the challenged transaction, the claims which the Objectors have asserted in the federal suit will likely be forever barred").

[6] Apart from any discussion of Delaware law, respondents contend that the settlement proceedings did not satisfy due process because the class was inadequately represented. See Brief for Respondents 34-45. Respondents make this claim in spite of the Chancery Court's express ruling, following argument on the issue, that the class representatives fairly and adequately protected the interests of the class. Cf. Prezant v. De Angelis, 636 A. 2d 915, 923 (Del. 1994) ("[The] constitutional requirement [of adequacy of representation] is embodied in [Delaware] Rule 23(a)(4), which requires that the named plaintiff `fairly and adequately protect the interests of the class' "). We need not address the due process claim, however, because it is outside the scope of the question presented in this Court. See Yee v. Escondido, 503 U. S. 519, 533 (1992). While it is true that a respondent may defend a judgment on alternative grounds, we generally do not address arguments that were not the basis for the decision below. See Peralta v. Heights Medical Center, Inc., 485 U. S. 80, 86 (1988).

[7] Respondents argue that their failure to opt out of the settlement class does not constitute consent to the terms of the settlement under traditional contract principles. Brief for Respondents 16-25. Again, the issue raised by respondents—whether the settlement could bar this suit as a matter of contract law, as distinguished from § 1738 law—is outside the scope of the question on which we granted certiorari. We note, however, that if a State chooses to approach the preclusive effect of a judgment embodying the terms of a settlement agreement as a question of pure contract law, a federal court must adhere to that approach under § 1738. Kremer v. Chemical Constr. Corp., 456 U. S. 461, 481-482 (1982).

[8] Though the plaintiff class premised one of its claims of fiduciary breach on the allegation that MCA wasted corporate assets by exposing the corporation to liability under the federal securities laws, the cause pleaded was nonetheless a state common-law action for breach of fiduciary duty.

[9] Kalb v. Feuerstein, 308 U. S. 433 (1940), is not to the contrary. In that case, the federal statute at issue expressly prohibited certain common-law actions from being either instituted or maintained in state court. Id., at 440-441. Thus, by merely entertaining a common-law foreclosure suit, over which it otherwise would have had jurisdiction, the state court violated the terms of the Act. That is not the situation here, where there is no contention that just by entertaining the class action the Delaware court acted in violation of federal law.

[10] Two sets of plaintiffs filed complaints in the Central District of California: the Epstein plaintiffs (including Lawrence Epstein, John Linder, Jane Rockford, Maurice Karlin, Ruth Karlin, Beth Karlin, and Bert Karlin) sued both individually and on behalf of all MCA shareholders at the time of the tender offer; Walter Minton brought suit in his individual capacity. All had tendered their shares for the $71 tender price. The District Court consolidated the two cases. Minton and, it appears, Rockford opted out of the Delaware class-action settlement. Matsushita does not contest the qualification of Minton and Rockford, as individuals, to pursue federal claims unimpeded by the settlement in Delaware. See Brief for Petitioners ii. Matsushita does contest any class-action initiative in federal court.

[11] The subsidiary in question was spun off from MCA during the merger because it owned a television station that federal law prohibited Matsushita from acquiring. The $71 tender offer price included $5 worth of stock in this new corporation.

[12] Closest in point, the court said, were Grimes v. Vitalink Communications Corp., 17 F. 3d 1553 (CA3 1994), and Nottingham Partners v. TransLux Corp., 925 F. 2d 29 (CA1 1991). See Epstein v. MCA, Inc., 50 F. 3d 644, 662 (CA9 1995).

[13] In its endeavor to forecast Delaware preclusion law, the Court appears to have blended the "identical factual predicate" test applied by the Delaware Supreme Court in Nottingham Partners v. Dana, 564 A. 2d 1089, 1106-1107 (1989), with the broader "same transaction" test advanced by Matsushita. See ante, at 376-378.

[14] Many States, including Delaware, have class-action rules corresponding to Federal Rule of Civil Procedure 23, a rule ranking adequacy of representation as a prerequisite to maintaining a class action. See 3 H. Newberg & A. Conte, Newberg on Class Actions, App. 13-1 (3d ed. 1992) (listing 39 States and the District of Columbia with rules comparable to the amended Federal Rule of Civil Procedure 23);Fed. Rule Civ. Proc. 23(a)(4) (representatives may sue on behalf of the class only if "the representative parties will fairlyand adequately protect the interests of the class"); see also General Telephone Co. of Southwest v. Falcon, 457 U. S. 147, 157-158, n. 13 (1982) (Federal Rule of Civil Procedure 23(a)(4)'s adequate representation requirement "raises concerns about the competency of class counsel and conflicts of interest," in addition to the question whether the representative shares the interests of the class members).

[15] Inboth Prezant and the instant case, a temporary settlement class device was used, telescoping the inquiry of adequate representation into the examination of the fairness of the settlement. According to the Delaware Supreme Court, however, this near simultaneity does not relieve the representative of her duty to demonstrate, nor the court of its duty to determine, the adequacy of representation. Prezant, 636 A. 2d,at 923. In a comprehensive opinion, the Third Circuit reached the same conclusion after examining the temporary class settlement device in the context of Federal Rule of Civil Procedure 23. See In re General Motors Corp. Pick-up Truck Fuel Tank Products Liability Litigation, 55 F. 3d 768, 794-800 (1995).

[16] The Vice Chancellor did not have the benefit of the Delaware Supreme Court's clear statement in Prezant, decided one year after this settlement was approved. In Prezant, however, the Delaware Supreme Court largely reiterated and applied what this Court had stated almost a decade earlier in Phillips Petroleum Co. v. Shutts, 472 U. S. 797, 808, 812 (1985). See also 2 R. Balotti & J. Finkelstein, Delaware Law of Corporations and Business Organization § 13.22,p.13-131, and n. 578 (2d ed. 1996 Supp.).

[17] The order approving the class for settlement purposes, the Epstein plaintiffs urge, contains no discussion of the adequacy of the representatives, see App. 198, and the order and final judgment approving the settlement contains only boilerplate language referring to the adequacy of representation, see id., at 204-205. The Delaware Supreme Court approved the Court of Chancery's judgment in a one paragraph order. See In re MCA, Inc. Shareholders Litigation, 633 A. 2d 370 (1993) (judgt. order).

[18] Delaware law appears to place the burden of proof on the classrepresentatives. See 2 Balotti & Finkelstein, supra, at 11, n. 7, § 13-17, p.13-121 (class representative must prove satisfaction of Del. Ch. Rule 23(a) requirements, including adequacy of representation); see also 7A C. Wright, A. Miller, & M. Kane, Federal Practice and Procedure § 1765, pp. 273-274, and n. 29 (2d ed. 1986); 3B J. Moore, Moore's Federal Practice § 23.02-2 (2d ed. 1995).

[19] In this regard, it is noteworthy that Matsushita did not move to dismiss the Delaware action after the Vice Chancellor, in rejecting the first proposed settlement, surveyed the state-law claims and found them insubstantial. See In re MCA, Inc. Shareholders Litigation, 598 A. 2d 687, 694 (Del. Ch. 1991) (Vice Chancellor described "the asserted state law claims" as "at best, extremely weak" and of "little or no value").

[20] Counsel for Matsushita acknowledged that relief from a judgment may be sought in Delaware pursuant to that State's counterpart to Federal Rule of Civil Procedure 60(b). See Tr. of Oral Arg. 51-52; Del. Ch. Rule 60; see also 2 Newberg & Conte, supra, at 9, n. 5, §§ 11.27, 11.63 (Federal Rule of Civil Procedure 60(b) provides an avenue to challenge the adequacy of representation in a class settlement).

[2372] Richard A. Monahan, for Petitioners.

Philip S. Beck, Chicago, IL, for Respondent.

Carter G. Phillips, Eric D. McArthur, Sidley Austin LLP, Washington, DC, Susan A. Weber, James R.M. Hemmings, Sidley Austin LLP, Chicago, IL, Philip S. Beck, Adam L. Hoeflich, Carolyn J. Frantz, Andrew C. Baak, Bartlit Beck Herman, Palencher & Scott LLP, Chicago, IL, Joshua J. Fougere, Sidley Austin LLP, for Respondent.

Richard A. Monahan, Marvin W. Masters, Charles M. Love, IV, The Masters Law Firm, Charleston, WV, for Petitioners.

Clinton A. Krislov, Counsel of Record, Eve-Lynn J. Rapp, Robert P. DeWitte, Krislov & Associates, Ltd., Chicago, IL, for Amici Thorogood and Murray.

Mark A. Boling, Law Offices of Mark Boling, Lake Forest, CA, for Amicus Martin Murray.

[2373] Justice KAGAN delivered the opinion of the Court.^[1]

In this case, a Federal District Court enjoined a state court from considering a plaintiff's request to approve a class action. The District Court did so because it had earlier denied a motion to certify a class in a related case, brought by a different plaintiff against the same defendant alleging similar claims. The federal court thought its injunction appropriate to prevent relitigation of the issue it had decided.

We hold to the contrary. In issuing this order to a state court, the federal court exceeded its authority under the "relitigation exception" to the Anti-Injunction Act. That statutory provision permits a federal court to enjoin a state proceeding only in rare cases, when necessary to "protect or effectuate [the federal court's] judgments." 28 U.S.C. § 2283. Here, that standard was not met for two reasons. First, the issue presented in the state court was not identical to the one decided in the federal tribunal. And second, the plaintiff in the state court did not have the requisite connection to the federal suit to be bound by the District Court's judgment.

I

Because the question before us involves the effect of a former adjudication on this case, we begin our statement of the facts not with this lawsuit, but with another. In August 2001, George McCollins sued respondent Bayer Corporation in the Circuit Court of Cabell County, West Virginia, asserting various state-law claims arising from Bayer's sale of an allegedly hazardous prescription drug called Baycol (which Bayer withdrew from the market that same month). McCollins contended that Bayer had violated West Virginia's consumer-protection statute and the company's express and implied warranties by selling him a defective product. And pursuant to West Virginia Rule of Civil Procedure 23 (2011), McCollins asked the state court to certify a class of West Virginia residents who had also purchased Baycol, so that the case could proceed as a class action.

Approximately one month later, the suit now before us began in a different part of West Virginia. Petitioners Keith Smith and Shirley Sperlazza (Smith for short) filed state-law claims against Bayer, similar to those raised in McCollins' suit, in the Circuit Court of Brooke County, West Virginia. And like McCollins, Smith asked the court to certify under West Virginia's Rule 23 a class of Baycol purchasers residing in the State. Neither Smith nor McCollins knew about the other's suit.

In January 2002, Bayer removed McCollins' case to the United States District Court for the Southern District of West Virginia on the basis of diversity jurisdiction. See 28 U.S.C. §§ 1332, 1441. The case was then transferred to the District of Minnesota pursuant to a preexisting order of the Judicial Panel on Multi-District Litigation, which had consolidated all federal suits involving Baycol (numbering in the tens of thousands) before a single District Court Judge. See § 1407. Bayer, however, could not remove Smith's case to federal court because Smith had sued several West Virginia defendants in addition to Bayer, and so the suit lacked complete diversity. See § 1441(b).^[2] Smith's suit [2374] thus remained in the state courthouse in Brooke County.

Over the next six years, the two cases proceeded along their separate pretrial paths at roughly the same pace. By 2008, both courts were preparing to turn to their respective plaintiffs' motions for class certification. The Federal District Court was the first to reach a decision.

Applying Federal Rule of Civil Procedure 23,^[3] the District Court declined to certify McCollins' proposed class of West Virginia Baycol purchasers. The District Court's reasoning proceeded in two steps. The court first ruled that, under West Virginia law, each plaintiff would have to prove "actual injury" from his use of Baycol to recover. App. to Pet. for Cert. 44a. The court then held that because the necessary showing of harm would vary from plaintiff to plaintiff, "individual issues of fact predominate[d]" over issues common to all members of the proposed class, and so the case was not suitable for class treatment. Id., at 45a. In the same order, the District Court also dismissed McCollins' claims on the merits in light of his failure to demonstrate physical injury from his use of Baycol. McCollins chose not to appeal.

Although McCollins' suit was now concluded, Bayer asked the District Court for another order based upon it, this one affecting Smith's case in West Virginia. In a motion—receipt of which first apprised Smith of McCollins' suit—Bayer explained that the proposed class in Smith's case was identical to the one the federal court had just rejected. Bayer therefore requested that the federal court enjoin the West Virginia state court from hearing Smith's motion to certify a class. According to Bayer, that order was appropriate to protect the District Court's judgment in McCollins' suit denying class certification. The District Court agreed and granted the injunction.

The Court of Appeals for the Eighth Circuit affirmed. In re Baycol Prods. Litigation, 593 F.3d 716 (2010). The court noted that the Anti-Injunction Act generally prohibits federal courts from enjoining state court proceedings. But the court held that the Act's relitigation exception authorized the injunction here because ordinary rules of issue preclusion barred Smith from seeking certification of his proposed class. According to the court, Smith was invoking a similar class action rule as McCollins had used to seek certification "of the same class" in a suit alleging "the same legal theories," id., at 724; the issue in the state court therefore was "sufficiently identical" to the one the federal court had decided to warrant preclusion, ibid. In addition, the court held, the parties in the two proceedings were sufficiently alike: Because Smith was an unnamed member of the class McCollins had proposed, and because their "interests were aligned," Smith was appropriately bound by the federal court's judgment. Ibid.

We granted certiorari, 561 U.S. ___, 131 S.Ct. 61, 177 L.Ed.2d 1150 (2010), because the order issued here implicates two circuit splits arising from application of the Anti-Injunction Act's relitigation exception. The first involves the requirement of preclusion law that a subsequent suit raise the "same issue" as a previous case.^[4] The second concerns the scope of [2375] the rule that a court's judgment cannot bind nonparties.^[5] We think the District Court erred on both grounds when it granted the injunction, and we now reverse.

II

The Anti-Injunction Act, first enacted in 1793, provides that

"A court of the United States may not grant an injunction to stay proceedings in a State court except as expressly authorized by Act of Congress, or where necessary in aid of its jurisdiction, or to protect or effectuate its judgments." 28 U.S.C. § 2283.

The statute, we have recognized, "is a necessary concomitant of the Framers' decision to authorize, and Congress' decision to implement, a dual system of federal and state courts." Chick Kam Choo v. Exxon Corp., 486 U.S. 140, 146, 108 S.Ct. 1684, 100 L.Ed.2d 127 (1988). And the Act's core message is one of respect for state courts. The Act broadly commands that those tribunals "shall remain free from interference by federal courts." Atlantic Coast Line R. Co. v. Locomotive Engineers, 398 U.S. 281, 282, 90 S.Ct. 1739, 26 L.Ed.2d 234 (1970). That edict is subject to only "three specifically defined exceptions." Id., at 286, 90 S.Ct. 1739. And those exceptions, though designed for important purposes, "are narrow and are `not [to] be enlarged by loose statutory construction.'" Chick Kam Choo, 486 U.S., at 146, 108 S.Ct. 1684 (quoting Atlantic Coast Line, 398 U.S., at 287, 90 S.Ct. 1739; alteration in original). Indeed, "[a]ny doubts as to the propriety of a federal injunction against state court proceedings should be resolved in favor of permitting the state courts to proceed." Id., at 297, 90 S.Ct. 1739.

This case involves the last of the Act's three exceptions, known as the relitigation exception. That exception is designed to implement "well-recognized concepts" of claim and issue preclusion. Chick Kam Choo, 486 U.S., at 147, 108 S.Ct. 1684. The provision authorizes an injunction to prevent state litigation of a claim or issue "that previously was presented to and decided by the federal court." Ibid. But in applying this exception, we have taken special care to keep it "strict and narrow." Id., at 148, 108 S.Ct. 1684. After all, a court does not usually "get to dictate to other courts the preclusion consequences of its own judgment." 18 C. Wright, A. Miller, & E. Cooper, Federal Practice and Procedure § 4405, p. 82 (2d ed.2002) (hereinafter Wright & Miller). Deciding whether and how prior litigation has preclusive effect is usually the bailiwick of the second court (here, the one in West Virginia). So issuing an injunction [2376] under the relitigation exception is resorting to heavy artillery.^[6] For that reason, every benefit of the doubt goes toward the state court, see Atlantic Coast Line, 398 U.S., at 287, 297, 90 S.Ct. 1739; an injunction can issue only if preclusion is clear beyond peradventure.

The question here is whether the federal court's rejection of McCollins' proposed class precluded a later adjudication in state court of Smith's certification motion. For the federal court's determination of the class issue to have this preclusive effect, at least two conditions must be met.^[7] First, the issue the federal court decided must be the same as the one presented in the state tribunal. See 18 Wright & Miller § 4417, at 412. And second, Smith must have been a party to the federal suit, or else must fall within one of a few discrete exceptions to the general rule against binding nonparties. See 18A id., § 4449, at 330. In fact, as we will explain, the issues before the two courts were not the same, and Smith was neither a party nor the exceptional kind of nonparty who can be bound. So the courts below erred in finding the certification issue precluded, and erred all the more in thinking an injunction appropriate.^[8]

A

In our most recent case on the relitigation exception, Chick Kam Choo v. Exxon, we applied the "same issue" requirement of preclusion law to invalidate a federal court's injunction. 486 U.S., at 151, 108 S.Ct. 1684. The federal court had dismissed a suit involving Singapore law on grounds of forum non conveniens. After the plaintiff brought the same claim in Texas state court, the federal court issued an injunction barring the plaintiff from pursuing relief in that alternate forum. We held that the District Court had gone too far. "[A]n essential prerequisite for applying the relitigation exception," we explained, "is that the . . . issues which the federal injunction insulates from litigation in state proceedings actually have been decided by the federal court." Id., at 148, 108 S.Ct. 1684. That prerequisite, we thought, was not satisfied because the issue to be adjudicated in state court was not the one the federal court had resolved. The federal court had considered the permissibility [2377] of the claim under federal forum non conveniens principles. But the Texas courts, we thought, "would apply a significantly different forum non conveniens analysis," id., at 149, 108 S.Ct. 1684; they had in prior cases rejected the strictness of the federal doctrine. Our conclusion followed: "[W]hether the Texas state courts are an appropriate forum for [the plaintiff's] Singapore law claims has not yet been litigated." Ibid. Because the legal standards in the two courts differed, the issues before the courts differed, and an injunction was unwarranted.

The question here closely resembles the one in Chick Kam Choo. The class Smith proposed in state court mirrored the class McCollins sought to certify in federal court: Both included all Baycol purchasers resident in West Virginia. Moreover, the substantive claims in the two suits broadly overlapped: Both complaints alleged that Bayer had sold a defective product in violation of the State's consumer protection law and the company's warranties. So far, so good for preclusion. But not so fast: a critical question—the question of the applicable legal standard—remains. The District Court ruled that the proposed class did not meet the requirements of Federal Rule 23 (because individualized issues would predominate over common ones). But the state court was poised to consider whether the proposed class satisfied West Virginia Rule 23. If those two legal standards differ (as federal and state forum non conveniens law differed in Chick Kam Choo)—then the federal court resolved an issue not before the state court. In that event, much like in Chick Kam Choo, "whether the [West Virginia] state cour[t]" should certify the proposed class action "has not yet been litigated." 486 U.S., at 149, 108 S.Ct. 1684.

The Court of Appeals and Smith offer us two competing ways of deciding whether the West Virginia and Federal Rules differ, but we think the right path lies somewhere in the middle. The Eighth Circuit relied almost exclusively on the near-identity of the two Rules' texts. See 593 F.3d, at 723. That was the right place to start, but not to end. Federal and state courts, after all, can and do apply identically worded procedural provisions in widely varying ways. If a State's procedural provision tracks the language of a Federal Rule, but a state court interprets that provision in a manner federal courts have not, then the state court is using a different standard and thus deciding a different issue. See 18 Wright & Miller § 4417, at 454 (stating that preclusion is "inappropriate" when "different legal standards . . . masquerad[e] behind similar legal labels"). At the other extreme, Smith contends that the source of law is all that matters: a different sovereign must in each and every case "have the opportunity, if it chooses, to construe its procedural rule differently." Brief for Petitioners 22 (quoting ALI, Principles of the Law, Aggregate Litigation § 2.11, Reporters' Notes, cmt. b, p. 181 (2010)). But if state courts have made crystal clear that they follow the same approach as the federal court applied, we see no need to ignore that determination; in that event, the issues in the two cases would indeed be the same. So a federal court considering whether the relitigation exception applies should examine whether state law parallels its federal counterpart. But as suggested earlier, see supra, at 2375-2376, the federal court must resolve any uncertainty on that score by leaving the question of preclusion to the state courts.

Under this approach, the West Virginia Supreme Court has gone some way toward resolving the matter before us by declaring its independence from federal courts' interpretation of the Federal Rules—and particularly of Rule 23. In In [2378] re W. Va. Rezulin Litigation, 214 W.Va. 52, 585 S.E.2d 52 (2003) (In re Rezulin), the West Virginia high court considered a plaintiff's motion to certify a class—coincidentally enough, in a suit about an allegedly defective pharmaceutical product. The court made a point of complaining about the parties' and lower court's near-exclusive reliance on federal cases about Federal Rule 23 to decide the certification question. Such cases, the court cautioned, "`may be persuasive, but [they are] not binding or controlling.'" Id., at 61, 585 S.E.2d, at 61. And lest anyone mistake the import of this message, the court went on: The aim of "this rule is to avoid having our legal analysis of our Rules `amount to nothing more than Pavlovian responses to federal decisional law.'" Ibid. (italics omitted). Of course, the state courts might still have adopted an approach to their Rule 23 that tracked the analysis the federal court used in McCollins' case. But absent clear evidence that the state courts had done so, we could not conclude that they would interpret their Rule in the same way. And if that is so, we could not tell whether the certification issues in the state and federal courts were the same. That uncertainty would preclude an injunction.

But here the case against an injunction is even stronger, because the West Virginia Supreme Court has disapproved the approach to Rule 23(b)(3)'s predominance requirement that the Federal District Court embraced. Recall that the federal court held that the presence of a single individualized issue—injury from the use of Baycol—prevented class certification. See supra, at 2373-2374. The court did not identify the common issues in the case; nor did it balance these common issues against the need to prove individual injury to determine which predominated. The court instead applied a strict test barring class treatment when proof of each plaintiff's injury is necessary.^[9] By contrast, the West Virginia Supreme Court in In re Rezulin adopted an all-things-considered, balancing inquiry in interpreting its Rule 23. Rejecting any "rigid test," the state court opined that the predominance requirement "contemplates a review of many factors." 214 W.Va., at 72, 585 S.E.2d, at 72. Indeed, the court noted, a "`single common issue'" in a case could outweigh "`numerous . . . individual questions.'" Ibid. That meant, the court further explained (quoting what it termed the "leading treatise" on the subject), that even objections to certification "`based on. . . causation, or reliance'"—which typically involve showings of individual injury—" `will not bar predominance satisfaction.'" Ibid. (quoting 2 A. Conte & H. Newberg, Newberg on Class Actions § 4.26, p. 241 (4th ed.2002)). So point for point, the analysis set out in In re Rezulin diverged from the District Court's interpretation of Federal Rule 23. A state court using the In re Rezulin standard would decide a different question than the one the federal court had earlier resolved.^[10]

[2379] This case, indeed, is little more than a rerun of Chick Kam Choo. A federal court and a state court apply different law. That means they decide distinct questions. The federal court's resolution of one issue does not preclude the state court's determination of another. It then goes without saying that the federal court may not issue an injunction. The Anti-Injunction Act's re-litigation exception does not extend nearly so far.

B

The injunction issued here runs into another basic premise of preclusion law: A court's judgment binds only the parties to a suit, subject to a handful of discrete and limited exceptions. See, e.g., 18A Wright & Miller § 4449, at 330. The importance of this rule and the narrowness of its exceptions go hand in hand. We have repeatedly "emphasize[d] the fundamental nature of the general rule" that only parties can be bound by prior judgments; accordingly, we have taken a "constrained approach to nonparty preclusion." Taylor v. Sturgell, 553 U.S. 880, 898, 128 S.Ct. 2161, 171 L.Ed.2d 155 (2008). Against this backdrop, Bayer defends the decision below by arguing that Smith—an unnamed member of a proposed but uncertified class—qualifies as a party to the McCollins litigation. See Brief for Respondent 32-34. Alternatively, Bayer claims that the District Court's judgment binds Smith under the recognized exception to the rule against nonparty preclusion for members of class actions. See id., at 34-39. We think neither contention has merit.

Bayer's first claim ill-comports with any proper understanding of what a "party" is. In general, "[a] `party' to litigation is `[o]ne by or against whom a lawsuit is brought,'" United States ex rel. Eisenstein v. City of New York, 556 U.S. ___, ___, 129 S.Ct. 2230, 2234, 173 L.Ed.2d 1255 (2009), or one who "become[s] a party by intervention, substitution, or third-party practice," Karcher v. May, 484 U.S. 72, 77, 108 S.Ct. 388, 98 L.Ed.2d 327 (1987). And we have further held that an unnamed member of a certified class may be "considered a `party' for the [particular] purpos[e] of appealing" an adverse judgment. Devlin v. Scardelletti, 536 U.S. 1, 7, 122 S.Ct. 2005, 153 L.Ed.2d 27 (2002). But as the dissent in Devlin noted, no one in that case was "willing to advance the novel and surely erroneous argument that a nonnamed class member is a party to the class-action litigation before the class is certified." Id., at 16, n. 1, 122 S.Ct. 2005 (opinion of SCALIA, J.). Still less does that argument make sense once certification is denied. The definition of the term "party" can on no account be stretched so far as to cover a person like Smith, whom the plaintiff in a lawsuit was denied leave to represent.^[11] If the [2380] judgment in the McCollins litigation can indeed bind Smith, it must do so under principles of non party preclusion.

As Bayer notes, see Brief for Respondent 37, one such principle allows unnamed members of a class action to be bound, even though they are not parties to the suit. See Cooper v. Federal Reserve Bank of Richmond, 467 U.S. 867, 874, 104 S.Ct. 2794, 81 L.Ed.2d 718 (1984) ("[U]nder elementary principles of prior adjudication a judgment in a properly entertained class action is binding on class members in any subsequent litigation"); see also Taylor, 553 U.S., at 894, 128 S.Ct. 2161 (stating that nonparties can be bound in "properly conducted class actions"). But here Bayer faces a conundrum. If we know one thing about the McCollins suit, we know that it was not a class action. Indeed, the very ruling that Bayer argues ought to be given preclusive effect is the District Court's decision that a class could not properly be certified. So Bayer wants to bind Smith as a member of a class action (because it is only as such that a nonparty in Smith's situation can be bound) to a determination that there could not be a class action. And if the logic of that position is not immediately transparent, here is Bayer's attempt to clarify: "[U]ntil the moment when class certification was denied, the McCollins case was a properly conducted class action." Brief for Respondent 37. That is true, according to Bayer, because McCollins' interests were aligned with the members of the class he proposed and he "act[ed] in a representative capacity when he sought class certification." Id., at 36.

But wishing does not make it so. McCollins sought class certification, but he failed to obtain that result. Because the District Court found that individual issues predominated, it held that the action did not satisfy Federal Rule 23's requirements for class proceedings. In these circumstances, we cannot say that a properly conducted class action existed at any time in the litigation. Federal Rule 23 determines what is and is not a class action in federal court, where McCollins brought his suit. So in the absence of a certification under that Rule, the precondition for binding Smith was not met. Neither a proposed class action nor a rejected class action may bind nonparties. What does have this effect is a class action approved under Rule 23. But McCollins' lawsuit was never that.

We made essentially these same points in Taylor v. Sturgell just a few Terms ago. The question there concerned the propriety of binding nonparties under a theory of "virtual representation" based on "identity of interests and some kind of relationship between parties and nonparties." 553 U.S., at 901, 128 S.Ct. 2161. We rejected the theory unanimously, explaining that it "would `recogniz[e], in effect, a common-law kind of class action.'" Ibid. Such a device, we objected, would authorize preclusion "shorn of [Rule 23's] procedural protections." Ibid. Or as otherwise stated in the opinion: We could not allow "circumvent[ion]" of Rule 23's protections [2381] through a "virtual representation doctrine that allowed courts to `create de facto class actions at will.'" Ibid. We could hardly have been more clear that a "properly conducted class action," with binding effect on nonparties, can come about in federal courts in just one way—through the procedure set out in Rule 23. Bayer attempts to distinguish Taylor by noting that the party in the prior litigation there did not propose a class action. But we do not see why that difference matters. Yes, McCollins wished to represent a class, and made a motion to that effect. But it did not come to pass. To allow McCollins' suit to bind nonparties would be to adopt the very theory Taylor rejected.^[12]

Bayer's strongest argument comes not from established principles of preclusion, but instead from policy concerns relating to use of the class action device. Bayer warns that under our approach class counsel can repeatedly try to certify the same class "by the simple expedient of changing the named plaintiff in the caption of the complaint." Brief for Respondent 47-48. And in this world of "serial relitigation of class certification," Bayer contends, defendants "would be forced in effect to buy litigation peace by settling." Id., at 2, 12; see also In re Bridgestone/Firestone, Inc., Tires Prods. Liability Litigation, 333 F.3d 763, 767 (C.A.7 2003) (objecting to an "an asymmetric system in which class counsel can win but never lose" because of their ability to relitigate the issue of certification).

But this form of argument flies in the face of the rule against nonparty preclusion. That rule perforce leads to relitigation of many issues, as plaintiff after plaintiff after plaintiff (none precluded by the last judgment because none a party to the last suit) tries his hand at establishing some legal principle or obtaining some grant of relief. We confronted a similar policy concern in Taylor, which involved litigation brought under the Freedom of Information Act (FOIA). The Government there cautioned that unless we bound nonparties a "`potentially limitless'" number of plaintiffs, perhaps coordinating with each other, could "mount a series of repetitive lawsuits" demanding the selfsame documents. 553 U.S., at 903, 128 S.Ct. 2161. But we rejected this argument, even though the payoff in a single successful FOIA suit—disclosure of documents to the public—could "trum[p]" or "subsum[e]" all prior losses, just as a single successful class certification motion could do. In re Bridgestone/Firestone, 333 F.3d, at 766, 767. As that response suggests, our legal system generally relies on principles of stare decisis and comity among courts to mitigate the sometimes substantial costs of similar litigation brought by different plaintiffs. We have not thought that the right approach (except in the discrete categories of cases we have recognized) lies in binding nonparties to a judgment.

And to the extent class actions raise special problems of relitigation, Congress [2382] has provided a remedy that does not involve departing from the usual rules of preclusion. In the Class Action Fairness Act of 2005 (CAFA), 28 U.S.C. §§ 1332(d), 1453 (2006 ed. and Supp. III), Congress enabled defendants to remove to federal court any sizable class action involving minimal diversity of citizenship. Once removal takes place, Federal Rule 23 governs certification. And federal courts may consolidate multiple overlapping suits against a single defendant in one court (as the Judicial Panel on Multi-District Litigation did for the many actions involving Baycol). See § 1407. Finally, we would expect federal courts to apply principles of comity to each other's class certification decisions when addressing a common dispute. See, e.g., Cortez Byrd Chips, Inc. v. Bill Harbert Constr. Co., 529 U.S. 193, 198, 120 S.Ct. 1331, 146 L.Ed.2d 171 (2000) (citing Landis v. North American Co., 299 U.S. 248, 254, 57 S.Ct. 163, 81 L.Ed. 153 (1936)). CAFA may be cold comfort to Bayer with respect to suits like this one beginning before its enactment. But Congress's decision to address the relitigation concerns associated with class actions through the mechanism of removal provides yet another reason for federal courts to adhere in this context to longstanding principles of preclusion.^[13] And once again, that is especially so when the federal court is deciding whether to go so far as to enjoin a state proceeding.

* * *

The Anti-Injunction Act prohibits the order the District Court entered here. The Act's relitigation exception authorizes injunctions only when a former federal adjudication clearly precludes a state-court decision. As we said more than 40 years ago, and have consistently maintained since that time, "[a]ny doubts ... should be resolved in favor of permitting the state courts to proceed." Atlantic Coast Line, 398 U.S., at 297, 90 S.Ct. 1739. Under this approach, close cases have easy answers: The federal court should not issue an injunction, and the state court should decide the preclusion question. But this case does not even strike us as close. The issues in the federal and state lawsuits differed because the relevant legal standards differed. And the mere proposal of a class in the federal action could not bind persons who were not parties there. For these reasons, the judgment of the Court of Appeals is

Reversed.

[1] Justice THOMAS joins Parts I and II-A of this opinion.

[2] The Class Action Fairness Act of 2005, 119 Stat. 4, which postdates and therefore does not govern this lawsuit, now enables a defendant to remove to federal court certain class actions involving nondiverse parties. See 28 U.S.C. §§ 1332(d), 1453(b); see also infra, at 2381-2382.

[3] Although McCollins had originally sought certification under West Virginia Rule of Civil Procedure 23 (2011), federal procedural rules govern a case that has been removed to federal court. See Shady Grove Orthopedic Associates, P.A. v. Allstate Ins. Co., 559 U.S. ___, 130 S.Ct. 1431, 176 L.Ed.2d 311 (2010).

[4] Compare In re Baycol Prods. Litigation, 593 F.3d 716, 723 (C.A.8 2010) (case below) (holding that two cases involve the same issue when "[t]he state and federal [class] certification rules . . . are not significantly different"), with J.R. Clearwater Inc. v. Ashland Chemical Co., 93 F.3d 176, 180 (C.A.5 1996) (holding that two cases implicate different issues even when "[the state rule] is modeled on . . . the Federal Rules" because a "[state] court might well exercise [its] discretion in a different manner").

[5] Compare 593 F.3d, at 724 ("[T]he denial of class certification is binding on unnamed [putative] class members" because they are "in privity to [the parties] in the prior action") and In re Bridgestone/Firestone, Inc., Tires Prods. Liability Litigation, 333 F.3d 763, 768-769 (C.A.7 2003) (same), with In re Ford Motor Co., 471 F.3d 1233, 1245 (C.A.11 2006) (holding that "[t]he denial of class certification" prevents a court from "binding" anyone other than "the parties appearing before it") and In re General Motors Corp. Pick-Up Truck Fuel Tank Prods. Liability Litigation, 134 F.3d 133, 141 (C.A.3 1998) (holding that putative "class members are not parties" and so cannot be bound by a court's ruling when "there is no class pending").

[6] That is especially so because an injunction is not the only way to correct a state trial court's erroneous refusal to give preclusive effect to a federal judgment. As we have noted before, "the state appellate courts and ultimately this Court" can review and reverse such a ruling. See Atlantic Coast Line R. Co. v. Locomotive Engineers, 398 U.S. 281, 287, 90 S.Ct. 1739, 26 L.Ed.2d 234 (1970).

[7] We have held that federal common law governs the preclusive effect of a decision of a federal court sitting in diversity. See Semtek Int'l Inc. v. Lockheed Martin Corp., 531 U.S. 497, 508, 121 S.Ct. 1021, 149 L.Ed.2d 32 (2001). Smith assumes that federal common law should here incorporate West Virginia's preclusion law, see Brief for Petitioners 15-16, whereas Bayer favors looking only to federal rules of preclusion because of the federal interests at stake in this case, see Brief for Respondent 18. We do not think the question matters here. Neither party identifies any way in which federal and state principles of preclusion law differ in any relevant respect. Nor have we found any such divergence. Compare, e.g., Montana v. United States, 440 U.S. 147, 153-154, 99 S.Ct. 970, 59 L.Ed.2d 210 (1979) (describing elements of issue preclusion), with State v. Miller, 194 W.Va. 3, 9, 459 S.E.2d 114, 120 (1995) (same). We therefore need not decide whether, in general, federal common law ought to incorporate state law in situations such as this.

[8] Because we rest our decision on the Anti-Injunction Act and the principles of issue preclusion that inform it, we do not consider Smith's argument, based on Phillips Petroleum Co. v. Shutts, 472 U.S. 797, 105 S.Ct. 2965, 86 L.Ed.2d 628 (1985), that the District Court's action violated the Due Process Clause.

[9] The District Court's approach to the predominance inquiry is consistent with the approach employed by the Eighth Circuit. See In re St. Jude Medical, Inc., 522 F.3d 836, 837-840 (2008) (holding that most commercial misrepresentation cases are "unsuitable for class treatment" because individual issues of reliance necessarily predominate). We express no opinion as to the correctness of this approach.

[10] Bayer argues that In re Rezulin does not preclude an injunction in this case because the West Virginia court there decided that common issues predominated over individual issues of damages, not over individual issues of liability (as exist here). See Brief for Respondent 25-26. We think Bayer is right about this distinction, but wrong about its consequence. Our point is not that In re Rezulin dictates the answer to the class certification question here; the two cases are indeed too dissimilar for that to be true. The point instead is that In re Rezulin articulated a general approach to the predominance requirement that differs markedly from the one the federal court used. Minor variations in the application of what is in essence the same legal standard do not defeat preclusion; but where, as here, the State's courts "would apply a significantly different . . . analysis," Chick Kam Choo v. Exxon Corp., 486 U.S. 140, 149, 108 S.Ct. 1684, 100 L.Ed.2d 127 (1988), the federal and state courts decide different issues.

[11] In support of its claim that Smith counts as a party, Bayer cites two cases in which we held that a putative member of an uncertified class may wait until after the court rules on the certification motion to file an individual claim or move to intervene in the suit. See Brief for Respondent 32-33 (citing United Airlines, Inc. v. McDonald, 432 U.S. 385, 97 S.Ct. 2464, 53 L.Ed.2d 423 (1977); American Pipe & Constr. Co. v. Utah, 414 U.S. 538, 94 S.Ct. 756, 38 L.Ed.2d 713 (1974)). But these cases, which were specifically grounded in policies of judicial administration, demonstrate only that a person not a party to a class suit may receive certain benefits (such as the tolling of a limitations period) related to that proceeding. See id., at 553, 94 S.Ct. 756; McDonald, 432 U.S., at 394, n. 15, 97 S.Ct. 2464. That result is consistent with a commonplace of preclusion law—that nonparties sometimes may benefit from, even though they cannot be bound by, former litigation. See Parklane Hosiery Co. v. Shore, 439 U.S. 322, 326-333, 99 S.Ct. 645, 58 L.Ed.2d 552 (1979); Blonder-Tongue Laboratories, Inc. v. University of Ill. Foundation, 402 U.S. 313, 91 S.Ct. 1434, 28 L.Ed.2d 788 (1971).

[12] The great weight of scholarly authority— from the Restatement of Judgments to the American Law Institute to Wright and Miller— agrees that an uncertified class action cannot bind proposed class members. See Restatement (Second) of Judgments § 41(1), p. 393 (1980) (A nonparty may be bound only when his interests are adequately represented by "[t]he representative of a class of persons similarly situated, designated as such with the approval of the court"); ALI, Principles of the Law Aggregate Litigation § 2.11, Reporters' Notes, cmt. b, p. 181 (2010) ("[N]one of [the exceptions to the rule against nonparty preclusion] extend generally to the situation of a would-be absent class member with respect to a denial of class certification"); 18A Wright & Miller § 4455, at 457-458 ("[A]bsent certification there is no basis for precluding a nonparty" under the class-action exception).

[13] By the same token, nothing in our holding today forecloses legislation to modify established principles of preclusion should Congress decide that CAFA does not sufficiently prevent relitigation of class certification motions. Nor does this opinion at all address the permissibility of a change in the Federal Rules of Civil Procedure pertaining to this question. Cf. n. 7, supra (declining to reach Smith's due process claim).

[374] Kenneth N. Flaxman (submitted), Attorney, Chicago, IL, for Plaintiffs-Appellees.

Michael Lambert Gallagher, Attorney, Office of the Cook County State's Attorney, Chicago, IL, for Defendants-Appellants.

Before POSNER, WOOD, and TINDER, Circuit Judges.

POSNER, Circuit Judge.

John Smentek and others, former inmates of Cook County Jail, are plaintiffs in this class action suit under 42 U.S.C. § 1983 against the County and its sheriff. The suit, filed in the federal district court in Chicago, charges that the defendants' failure to make more than a single dentist available to the jail's 10,000 inmates constitutes the imposition of cruel and unusual punishment and thus violates both the Eighth Amendment and the due process clause of the Fourteenth Amendment.

Most people held in jails as distinct from prisons, including most members of the plaintiff class, are pretrial detainees, and the cruel and unusual punishments clause does not apply to persons who though incarcerated have not been convicted and so are not being subjected to "punishment." But the due process clause has been interpreted to provide equivalent protection. E.g., Zentmyer v. Kendall County, 220 F.3d 805, 810 (7th Cir.2000). It is because some of the members of the class are convicts housed in Cook County Jail that the suit advances claims under both amendments.

Vincent Smith, another former inmate of Cook County Jail, had brought a nearly identical suit prior to Smentek's bringing this one. Smith had asked the district court to certify a class consisting of "all persons who, while confined at Cook County Jail on and after June 29, 2005, requested but were not given timely treatment for dental pain." The district judge denied class certification in May 2008. Nine months later a different district judge in the same court denied class certification in a materially identical class action suit by still another former inmate of Cook County Jail, Lance Wrightsell. Then came Smentek, the third materially identical suit, filed in the same court in January 2009 and assigned to still another district [375] judge. We don't understand why all three cases were not assigned to the same judge. Besides the usual advantages of consolidation, it would have avoided the problem that has precipitated the appeal in this case, because a single judge would not be of different minds about three identical lawsuits.

Initially the district judge assigned to this case denied class certification on the ground that the denial in the two preceding class action suits (Smith and Wrightsell) barred, by operation of collateral estoppel, the grant of certification in the third. But the judge reversed her ruling and granted certification after the Supreme Court held in Smith v. Bayer Corp., ___ U.S. ___, 131 S.Ct. 2368, 180 L.Ed.2d 341 (2011), that "neither a proposed class action nor a rejected class action may bind nonparties. What does have this effect is a class action approved under Rule 23 [of the Federal Rules of Civil Procedure]." Id. at 2380. "The definition of the term `party' can on no account be stretched so far as to cover a person... whom the plaintiff in a lawsuit was denied leave to represent." Id. at 2379. We applied the Court's holding in Thorogood v. Sears, Roebuck & Co., 678 F.3d 546 (7th Cir.2012), a case like the present one in which, after denial of class certification (one denial, not two as in this case), an unnamed class member filed an identical class action suit, though in a different court.

The Court in Smith v. Bayer Corp. suggested other means for limiting copycat class action litigation besides preclusion, and the defendants in the present case, who have petitioned us for leave to appeal under Fed.R.Civ.P. 23(f) from the grant of class certification, have fastened on one of them: "we would expect federal courts to apply principles of comity to each other's class certification decisions when addressing a common dispute. See, e.g., Cortez Byrd Chips, Inc. v. Bill Harbert Construction Co., 529 U.S. 193, 198, 120 S.Ct. 1331, 146 L.Ed.2d 171 (2000) (citing Landis v. North American Co., 299 U.S. 248, 254, 57 S.Ct. 163, 81 L.Ed. 153 (1936))." 131 S.Ct. at 2382.

We have granted the Rule 23(f) petition, limited to the question of when a district court, in deciding whether to certify a class, should "defer, based on the principles of comity, to a sister court's ruling on a motion for certification of a similar class."

The Court's reference to "comity" in Smith v. Bayer Corp. was cryptic. Neither of the two cases that the Court cited — Cortez and Landis — discusses comity; Cortez doesn't even mention the word. Both are cases about whether to stay one of two pending parallel suits, a question not presented by either this case or Smith v. Bayer Corp. No more than the two cases that the Court cited does Smith v. Bayer Corp. itself discuss the concept. And the similar suits at issue in that case were in different court systems — state and federal.

A standard definition of "comity" is "the respect that sovereign nations (or quasi-sovereigns such as the states of the United States) owe each other." Philips Medical Systems Int'l B.V. v. Bruetman, 8 F.3d 600, 604 (7th Cir.1993); see also Younger v. Harris, 401 U.S. 37, 44, 91 S.Ct. 746, 27 L.Ed.2d 669 (1971); Bank of Augusta v. Earle, 38 U.S. 519, 589, 13 Pet. 519, 10 L.Ed. 274 (1839); United States v. Kashamu, 656 F.3d 679, 683 (7th Cir.2011); JP Morgan Chase Bank v. Altos Hornos de Mexico, S.A. de C.V., 412 F.3d 418, 423-24 (2d Cir.2005). That was a consideration in Smith v. Bayer Corp., because the first class action had been filed in a state court and the copycat class action in a federal court; it is not a factor here, where all [376] three suits were filed in federal court and based on federal law. But as in such cases as Landis, the word "comity" is used in a looser sense to caution judges against stepping on each other's toes when parallel suits are pending in different courts. See Texas Independent Producers & Royalty Owners Ass'n v. EPA, 410 F.3d 964, 980 (7th Cir.2005); Certified Restoration Dry Cleaning Network, L.L.C. v. Tenke Corp., 511 F.3d 535, 551-52 (6th Cir.2007); Ulmet v. United States, 888 F.2d 1028, 1031 (4th Cir.1989). This is not such a case either, however, not only because only one court (though more than one judge) is hosting the parallel suits but also because the Smith and Wrightsell cases were over when Judge Lefkow granted the motion for class certification in the present case.

The version of comity announced in dictum in Smith v. Bayer Corp. is novel. It does not involve the mutual respect of sovereigns or quasi-sovereigns and it does not appear to be limited to cases in which parallel suits are pending in different courts (or before different judges) of the same sovereign. If it were so limited, it would have no application if the other parallel suits had been resolved, which may be true here, since class certification in the other Cook County Jail dental cases was denied — or at least very little application, since those cases may continue as individual suits by the former class representatives. The Supreme Court's opinion cites no authority for the extension of the doctrine of comity to mere disagreement between federal judges, and despite the reference to expecting "federal courts to apply principles of comity to each other's class certification decisions" (emphasis added), the Court seems really to have been thinking about cases involving federal-state comity, of which Smith v. Bayer Corp. was one.

Whatever the scope of the Supreme Court's current concept of comity, the defendants' argument that Smith v. Bayer Corp. adopted a rule of comity in class action suits that precludes granting class certification in a copycat class action must be rejected; for if the Court had adopted such a rule it would have affirmed the injunction granted in the district court in that case (and affirmed by the court of appeals) against the copycat class action suit, instead of reversing, as it did. It would have been adopting a rule of preclusion rather than rejecting such a rule. True, the effect of the doctrine of comity, when it is successfully invoked, is preclusive. But unlike res judicata, it is a doctrine that does not require but merely permits preclusion, except (as we're about to see) when it governs choice of forum. The mandatory comity for which the defendants in our case contend is just another name for collateral estoppel. The defendants are wrong to think comity a synonym for collateral estoppel, which if true would as we said have required affirmance in Smith v. Bayer Corp.

One can imagine the Supreme Court's ruling that comity between district judges in class certification cases is a doctrine of preclusion, but there's no suggestion of that in Smith v. Bayer Corp. and it would be a surprising rule. It would give comity greater force between two judges of the same court than between two nations each jealous of its sovereign authority and demanding respect from other nations. Not that there isn't a serious problem of judge shopping in the disordered realm of class action litigation, a problem well illustrated by this case and its two predecessors taken all together. Without a rule of preclusion, class action lawyers can do what the lawyer here (and the lawyer in Thorogood) did: keep bringing identical class actions with new class representatives until they draw a judge who is willing to [377] certify the class. We are troubled to learn that when the district judge in this case certified the class there were twelve Cook County Jail dental suits pending in the Northern District of Illinois in addition to the two (Wrightsell and Smith) in which certification had been rejected, though we don't know in how many of these cases class certification was sought.

But what is the solution to the judge-shopping problem? How are courts or legislatures to prevent class action litigation from metastasizing? The rule urged by the defendants in this case that the denial of class certification bars the certification of the same or a similar class in a suit by a member of the same class as the previous suit might do the trick, but it would contradict the holding of Smith v. Bayer Corp., which is that a class member who did not become a party to the previous parallel class action is not precluded from seeking class certification in his class action. Cases such as Fair Assessment in Real Estate Association, Inc. v. McNary, 454 U.S. 100, 103-05, 102 S.Ct. 177, 70 L.Ed.2d 271 (1981); Great Lakes Dredge & Dock Co. v. Huffman, 319 U.S. 293, 63 S.Ct. 1070, 87 L.Ed. 1407 (1943); Younger v. Harris, supra, 401 U.S. at 43-44, 91 S.Ct. 746, and Hoover v. Wagner, 47 F.3d 845, 851 (7th Cir.1995), which in the name of comity bar a plaintiff from one forum because another is deemed more appropriate, are not in point; if Smentek and the other named plaintiffs are barred from seeking class certification by virtue of the previous denials, they cannot bring a class action anywhere else. They could file a class action claim in an Illinois state court, but the defendants' concept of comity would require the state court to dismiss it. Yet theirs is the kind of case that as a practical matter probably cannot be litigated other than as a class action because most cases of delayed treatment of dental pain do not hold out a prospect of significant damages.

We are left with the weak notion of "comity" as requiring a court to pay respectful attention to the decision of another judge in a materially identical case, but no more than that even if it is a judge of the same court or a judge of a different court within the same judiciary. We emphasize, however, the qualification in "materially identical." Even two class actions involving the same class may differ materially, for example in the suitability of the class representative or the adequacy of class counsel, and where they do the judge in the second, or third, or nth class action is on his own. This is not such a case; nevertheless the district judge gave plausible reasons for her disagreement with the judges in the two previous Cook County dental cases. Can more be required? The defendants' claim that she was bound by the decisions of the other judges just because those decisions preceded and were contrary to her decision has no basis in law and flouts the principle that a district court decision does not have precedential effect. Camreta v. Greene, ___ U.S. ___, 131 S.Ct. 2020, 2033 n. 7, 179 L.Ed.2d 1118 (2011); Wirtz v. City of South Bend, 669 F.3d 860, 862-63 (7th Cir.2012). The defendants would have such decisions treated not as mere precedents but as super-precedents that no court lacking appellate authority could question.

The district judge's grant of class certification is therefore affirmed. But this is not to say that the judge's ruling was correct; maybe the other two judges were correct. The appeal asks us to decide only whether comity between federal district judges' rulings on class certification is preclusive. We have decided: it is not.

[1435] Scott L. Nelson, Washington, DC, for petitioner.

Christopher Landau, Washington, DC, for respondent.

John S. Spadaro, John Sheehan Spadaro, LLC, Hockessin, DE, Scott L. Nelson, Counsel of Record, Brian Wolfman, Public [1436] Citizen Litigation Group, Washington, DC for petitioner.

Andrew T. Hahn, Sr., Seyfarth Shaw LLP, New York, NY, Christopher Landau, P.C., Counsel of Record, Britt C. Grant, Kirkland & Ellis LLP, Washington, DC, for respondent.

Justice SCALIA announced the judgment of the Court and delivered the opinion of the Court with respect to Parts I and II-A, an opinion with respect to Parts II-B and II-D, in which THE CHIEF JUSTICE, Justice THOMAS, and Justice SOTOMAYOR join, and an opinion with respect to Part II-C, in which THE CHIEF JUSTICE and Justice THOMAS join.

New York law prohibits class actions in suits seeking penalties or statutory minimum damages.^[1] We consider whether this precludes a federal district court sitting in diversity from entertaining a class action under Federal Rule of Civil Procedure 23.^[2]

I

The petitioner's complaint alleged the following: Shady Grove Orthopedic Associates, P. A., provided medical care to Sonia E. Galvez for injuries she suffered in an automobile accident. As partial payment for that care, Galvez assigned to Shady Grove her rights to insurance benefits under a policy issued in New York by Allstate Insurance Co. Shady Grove tendered a claim for the assigned benefits to Allstate, which under New York law had 30 days to pay the claim or deny it. See N.Y. Ins. Law Ann. § 5106(a) (West 2009). Allstate apparently paid, but not on time, and it refused to pay the statutory interest that accrued on the overdue benefits (at two percent per month), see ibid.

Shady Grove filed this diversity suit in the Eastern District of New York to recover the unpaid statutory interest. Alleging that Allstate routinely refuses to pay interest on overdue benefits, Shady Grove [1437] sought relief on behalf of itself and a class of all others to whom Allstate owes interest. The District Court dismissed the suit for lack of jurisdiction. 466 F.Supp.2d 467 (2006). It reasoned that N.Y. Civ. Prac. Law Ann. § 901(b), which precludes a suit to recover a "penalty" from proceeding as a class action, applies in diversity suits in federal court, despite Federal Rule of Civil Procedure 23. Concluding that statutory interest is a "penalty" under New York law, it held that § 901(b) prohibited the proposed class action. And, since Shady Grove conceded that its individual claim (worth roughly $500) fell far short of the amount-in-controversy requirement for individual suits under 28 U.S.C. § 1332(a), the suit did not belong in federal court.^[3]

The Second Circuit affirmed. 549 F.3d 137 (2008). The court did not dispute that a federal rule adopted in compliance with the Rules Enabling Act, 28 U.S.C. § 2072, would control if it conflicted with § 901(b). But there was no conflict because (as we will describe in more detail below) the Second Circuit concluded that Rule 23 and § 901(b) address different issues. Finding no federal rule on point, the Court of Appeals held that § 901(b) is "substantive" within the meaning of Erie R. Co. v. Tompkins, 304 U.S. 64, 58 S.Ct. 817, 82 L.Ed. 1188 (1938), and thus must be applied by federal courts sitting in diversity.

We granted certiorari, ___ U.S. ___, 129 S.Ct. 2160, 173 L.Ed.2d 1155 (2009).

II

The framework for our decision is familiar. We must first determine whether Rule 23 answers the question in dispute. Burlington Northern R. Co. v. Woods, 480 U.S. 1, 4-5, 107 S.Ct. 967, 94 L.Ed.2d 1 (1987). If it does, it governs—New York's law notwithstanding—unless it exceeds statutory authorization or Congress's rulemaking power. Id. at 5, 107 S.Ct. 967; see Hanna v. Plumer, 380 U.S. 460, 463-464, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965). We do not wade into Erie's murky waters unless the federal rule is inapplicable or invalid. See 380 U.S. at 469-471, 85 S.Ct. 1136.

A

The question in dispute is whether Shady Grove's suit may proceed as a class action. Rule 23 provides an answer. It states that "[a] class action may be maintained" if two conditions are met: The suit must satisfy the criteria set forth in subdivision (a) (i.e., numerosity, commonality, typicality, and adequacy of representation), and it also must fit into one of the three categories described in subdivision (b). Fed. Rule Civ. Proc. 23(b). By its terms this creates a categorical rule entitling a plaintiff whose suit meets the specified criteria to pursue his claim as a class action. (The Federal Rules regularly use "may" to confer categorical permission, see, e.g., Fed. Rules Civ. Proc. 8(d)(2)-(3), 14(a)(1), 18(a)-(b), 20(a)(1)-(2), 27(a)(1), 30(a)(1), as do federal statutes that establish procedural entitlements, see, e.g., 29 U.S.C. § 626(c)(1); 42 U.S.C. § 2000e-5(f)(1).) Thus, Rule 23 provides a one-size-fits-all formula for deciding the class-action question. Because § 901(b) attempts to answer the same question—i.e., it states that Shady Grove's suit "may not be maintained as a class action" (emphasis added) because of the relief it seeks—it cannot apply in diversity suits unless Rule 23 is ultra vires.

[1438] The Second Circuit believed that § 901(b) and Rule 23 do not conflict because they address different issues. Rule 23, it said, concerns only the criteria for determining whether a given class can and should be certified; section 901(b), on the other hand, addresses an antecedent question: whether the particular type of claim is eligible for class treatment in the first place—a question on which Rule 23 is silent. See 549 F.3d at 143-144. Allstate embraces this analysis. Brief for Respondent 12-13.

We disagree. To begin with, the line between eligibility and certifiability is entirely artificial. Both are preconditions for maintaining a class action. Allstate suggests that eligibility must depend on the "particular cause of action" asserted, instead of some other attribute of the suit, id. at 12. But that is not so. Congress could, for example, provide that only claims involving more than a certain number of plaintiffs are "eligible" for class treatment in federal court. In other words, relabeling Rule 23(a)'s prerequisites "eligibility criteria" would obviate Allstate's objection—a sure sign that its eligibility-certifiability distinction is made-to-order.

There is no reason, in any event, to read Rule 23 as addressing only whether claims made eligible for class treatment by some other law should be certified as class actions. Allstate asserts that Rule 23 neither explicitly nor implicitly empowers a federal court "to certify a class in each and every case" where the Rule's criteria are met. Id. at 13-14. But that is exactly what Rule 23 does: It says that if the prescribed preconditions are satisfied "[a] class action may be maintained" (emphasis added)—not "a class action may be permitted." Courts do not maintain actions; litigants do. The discretion suggested by Rule 23's "may" is discretion residing in the plaintiff: He may bring his claim in a class action if he wishes. And like the rest of the Federal Rules of Civil Procedure, Rule 23 automatically applies "in all civil actions and proceedings in the United States district courts," Fed. Rule Civ. Proc. 1. See Califano v. Yamasaki, 442 U.S. 682, 699-700, 99 S.Ct. 2545, 61 L.Ed.2d 176 (1979).

Allstate points out that Congress has carved out some federal claims from Rule 23's reach, see, e.g., 8 U.S.C. § 1252(e)(1)(B)—which shows, Allstate contends, that Rule 23 does not authorize class actions for all claims, but rather leaves room for laws like § 901(b). But Congress, unlike New York, has ultimate authority over the Federal Rules of Civil Procedure; it can create exceptions to an individual rule as it sees fit—either by directly amending the rule or by enacting a separate statute overriding it in certain instances. Cf. Henderson v. United States, 517 U.S. 654, 668, 116 S.Ct. 1638, 134 L.Ed.2d 880 (1996). The fact that Congress has created specific exceptions to Rule 23 hardly proves that the Rule does not apply generally. In fact, it proves the opposite. If Rule 23 did not authorize class actions across the board, the statutory exceptions would be unnecessary.

Allstate next suggests that the structure of § 901 shows that Rule 23 addresses only certifiability. Section 901(a), it notes, establishes class-certification criteria roughly analogous to those in Rule 23 (wherefore it agrees that subsection is preempted). But § 901(b)'s rule barring class actions for certain claims is set off as its own subsection, and where it applies § 901(a) does not. This shows, according to Allstate, that § 901(b) concerns a separate subject. Perhaps it does concern a subject separate from the subject of § 901(a). But the question before us is [1439] whether it concerns a subject separate from the subject of Rule 23—and for purposes of answering that question the way New York has structured its statute is immaterial. Rule 23 permits all class actions that meet its requirements, and a State cannot limit that permission by structuring one part of its statute to track Rule 23 and enacting another part that imposes additional requirements. Both of § 901's subsections undeniably answer the same question as Rule 23: whether a class action may proceed for a given suit. Cf. Burlington, 480 U.S. at 7-8, 107 S.Ct. 967.

The dissent argues that § 901(b) has nothing to do with whether Shady Grove may maintain its suit as a class action, but affects only the remedy it may obtain if it wins. See post at 1464-1469 (opinion of GINSBURG, J.). Whereas "Rule 23 governs procedural aspects of class litigation" by "prescrib[ing] the considerations relevant to class certification and postcertification proceedings," § 901(b) addresses only "the size of a monetary award a class plaintiff may pursue." Post at 1465-1466. Accordingly, the dissent says, Rule 23 and New York's law may coexist in peace.

We need not decide whether a state law that limits the remedies available in an existing class action would conflict with Rule 23; that is not what § 901(b) does. By its terms, the provision precludes a plaintiff from "maintain[ing]" a class action seeking statutory penalties. Unlike a law that sets a ceiling on damages (or puts other remedies out of reach) in properly filed class actions, § 901(b) says nothing about what remedies a court may award; it prevents the class actions it covers from coming into existence at all.^[4] Consequently, a court bound by § 901(b) could not certify a class action seeking both statutory penalties and other remedies even if it announces in advance that it will refuse to award the penalties in the event the plaintiffs prevail; to do so would violate the statute's clear prohibition on "maintain[ing]" such suits as class actions.

The dissent asserts that a plaintiff can avoid § 901(b)'s barrier by omitting from his complaint (or removing) a request for statutory penalties. See post at 1467-1468. Even assuming all statutory penalties are waivable,^[5] the fact that a complaint omitting them could be brought as a class action would not at all prove that § 901(b) is addressed only to remedies. If the state law instead banned class actions for fraud claims, a would-be class-action plaintiff could drop the fraud counts from his complaint and proceed with the remainder in a class action. Yet that would not mean the law provides no remedy for fraud; the ban would affect only the procedural means by which the remedy may be pursued. In short, although the dissent correctly abandons Allstate's eligibility-certifiability distinction, [1440] the alternative it offers fares no better.

The dissent all but admits that the literal terms of § 901(b) address the same subject as Rule 23—i.e., whether a class action may be maintained—but insists the provision's purpose is to restrict only remedies. See post at 1466-1468; post at 1467 ("[W]hile phrased as responsive to the question whether certain class actions may begin, § 901(b) is unmistakably aimed at controlling how those actions must end"). Unlike Rule 23, designed to further procedural fairness and efficiency, § 901(b) (we are told) "responds to an entirely different concern": the fear that allowing statutory damages to be awarded on a class-wide basis would "produce overkill." Post at 1466, 1464 (internal quotation marks omitted). The dissent reaches this conclusion on the basis of (1) constituent concern recorded in the law's bill jacket; (2) a commentary suggesting that the Legislature "apparently fear[ed]" that combining class actions and statutory penalties "could result in annihilating punishment of the defendant," V. Alexander, Practice Commentaries, C901:11, reprinted in 7B McKinney's Consolidated Laws of New York Ann., p. 104 (2006) (internal quotation marks omitted); (3) a remark by the Governor in his signing statement that § 901(b) "`provides a controlled remedy,'" post at 1464 (quoting Memorandum on Approving L. 1975, Ch. 207, reprinted in 1975 N.Y. Laws, at 1748; emphasis deleted), and (4) a state court's statement that the final text of § 901(b) "`was the result of a compromise among competing interests,'" post at 1464 (quoting Sperry v. Crompton Corp., 8 N.Y.3d 204, 211, 831 N.Y.S.2d 760, 863 N.E.2d 1012, 1015 (2007)).

This evidence of the New York Legislature's purpose is pretty sparse. But even accepting the dissent's account of the Legislature's objective at face value, it cannot override the statute's clear text. Even if its aim is to restrict the remedy a plaintiff can obtain, § 901(b) achieves that end by limiting a plaintiff's power to maintain a class action. The manner in which the law "could have been written," post at 1472, has no bearing; what matters is the law the Legislature did enact. We cannot rewrite that to reflect our perception of legislative purpose, see Oncale v. Sundowner Offshore Services, Inc., 523 U.S. 75, 79-80, 118 S.Ct. 998, 140 L.Ed.2d 201 (1998).^[6] The dissent's concern for state prerogatives is frustrated rather than furthered by revising state laws when a potential conflict with a Federal Rule arises; the statefriendly approach would be to accept the law as written and test the validity of the Federal Rule.

The dissent's approach of determining whether state and federal rules conflict based on the subjective intentions of the [1441] state legislature is an enterprise destined to produce "confusion worse confounded," Sibbach v. Wilson & Co., 312 U.S. 1, 14, 61 S.Ct. 422, 85 L.Ed. 479 (1941). It would mean, to begin with, that one State's statute could survive pre-emption (and accordingly affect the procedures in federal court) while another State's identical law would not, merely because its authors had different aspirations. It would also mean that district courts would have to discern, in every diversity case, the purpose behind any putatively pre-empted state procedural rule, even if its text squarely conflicts with federal law. That task will often prove arduous. Many laws further more than one aim, and the aim of others may be impossible to discern. Moreover, to the extent the dissent's purpose-driven approach depends on its characterization of § 901(b)'s aims as substantive, it would apply to many state rules ostensibly addressed to procedure. Pleading standards, for example, often embody policy preferences about the types of claims that should succeed—as do rules governing summary judgment, pretrial discovery, and the admissibility of certain evidence. Hard cases will abound. It is not even clear that a state supreme court's pronouncement of the law's purpose would settle the issue, since existence of the factual predicate for avoiding federal pre-emption is ultimately a federal question. Predictably, federal judges would be condemned to poring through state legislative history—which may be less easily obtained, less thorough, and less familiar than its federal counterpart, see R. Mersky & D. Dunn, Fundamentals of Legal Research 233 (8th ed.2002); Torres & Windsor, State Legislative Histories: A Select, Annotated Bibliography, 85 L. Lib. J. 545, 547 (1993).

But while the dissent does indeed artificially narrow the scope of § 901(b) by finding that it pursues only substantive policies, that is not the central difficulty of the dissent's position. The central difficulty is that even artificial narrowing cannot render § 901(b) compatible with Rule 23. Whatever the policies they pursue, they flatly contradict each other. Allstate asserts (and the dissent implies, see post at 1461, 1465-1466) that we can (and must) interpret Rule 23 in a manner that avoids overstepping its authorizing statute.^[7] If the Rule were susceptible of two meanings—one that would violate § 2072(b) and another that would not—we would agree. See Ortiz v. Fibreboard Corp., 527 U.S. 815, 842, 845, 119 S.Ct. 2295, 144 L.Ed.2d [1442] 715 (1999); cf. Semtek Int'l Inc. v. Lockheed Martin Corp., 531 U.S. 497, 503-504, 121 S.Ct. 1021, 149 L.Ed.2d 32 (2001). But it is not. Rule 23 unambiguously authorizes any plaintiff, in any federal civil proceeding, to maintain a class action if the Rule's prerequisites are met. We cannot contort its text, even to avert a collision with state law that might render it invalid. See Walker v. Armco Steel Corp., 446 U.S. 740, 750, n. 9, 100 S.Ct. 1978, 64 L.Ed.2d 659 (1980).^[8] What the dissent's approach achieves is not the avoiding of a "conflict between Rule 23 and § 901(b)," post at 1469, but rather the invalidation of Rule 23 (pursuant to § 2072(b) of the Rules Enabling Act) to the extent that it conflicts with the substantive policies of § 901. There is no other way to reach the dissent's destination. We must therefore confront head-on whether Rule 23 falls within the statutory authorization.

B

Erie involved the constitutional power of federal courts to supplant state law with judge-made rules. In that context, it made no difference whether the rule was technically one of substance or procedure; the touchstone was whether it "significantly affect[s] the result of a litigation." Guaranty Trust Co. v. York, 326 U.S. 99, 109, 65 S.Ct. 1464, 89 L.Ed. 2079 (1945). That is not the test for either the constitutionality or the statutory validity of a Federal Rule of Procedure. Congress has undoubted power to supplant state law, and undoubted power to prescribe rules for the courts it has created, so long as those rules regulate matters "rationally capable of classification" as procedure. Hanna, 380 U.S. at 472, 85 S.Ct. 1136. In the Rules Enabling Act, Congress authorized this Court to promulgate rules of procedure subject to its review, 28 U.S.C. § 2072(a), but with the limitation that those rules "shall not abridge, enlarge or modify any substantive right," § 2072(b).

We have long held that this limitation means that the Rule must "really regulat[e] procedure,—the judicial process for enforcing rights and duties recognized by substantive law and for justly administering remedy and redress for disregard or infraction of them," Sibbach, 312 U.S. at 14, 61 S.Ct. 422; see Hanna, supra at 464, 85 S.Ct. 1136; Burlington, 480 U.S. at 8, 107 S.Ct. 967. The test is not whether the rule affects a litigant's substantive rights; most procedural rules do. Mississippi Publishing Corp. v. Murphree, 326 U.S. 438, 445, 66 S.Ct. 242, 90 L.Ed. 185 (1946). What matters is what the rule itself regulates: If it governs only "the manner and the means" by which the litigants' rights are "enforced," it is valid; if it alters "the rules of decision by which [the] court will adjudicate [those] rights," it is not. Id. at 446, 66 S.Ct. 242 (internal quotation marks omitted).

Applying that test, we have rejected every statutory challenge to a Federal Rule that has come before us. We have found to be in compliance with § 2072(b) rules prescribing methods for serving process, see id. at 445-446, 66 S.Ct. 242 (Fed. Rule Civ. Proc. 4(f)); Hanna, supra at 463-465, 85 S.Ct. 1136 (Fed. Rule Civ. Proc. 4(d)(1)), and requiring litigants whose mental or physical condition is in dispute to submit to examinations, see Sibbach, supra at 14-16, 61 S.Ct. 422 (Fed. Rule Civ. Proc. 35); Schlagenhauf v. Holder, [1443] 379 U.S. 104, 113-114, 85 S.Ct. 234, 13 L.Ed.2d 152 (1964) (same). Likewise, we have upheld rules authorizing imposition of sanctions upon those who file frivolous appeals, see Burlington, supra at 8, 107 S.Ct. 967 (Fed. Rule App. Proc. 38), or who sign court papers without a reasonable inquiry into the facts asserted, see Business Guides, Inc. v. Chromatic Communications Enterprises, Inc., 498 U.S. 533, 551-554, 111 S.Ct. 922, 112 L.Ed.2d 1140 (1991) (Fed. Rule Civ. Proc. 11). Each of these rules had some practical effect on the parties' rights, but each undeniably regulated only the process for enforcing those rights; none altered the rights themselves, the available remedies, or the rules of decision by which the court adjudicated either.

Applying that criterion, we think it obvious that rules allowing multiple claims (and claims by or against multiple parties) to be litigated together are also valid. See, e.g., Fed. Rules Civ. Proc. 18 (joinder of claims), 20 (joinder of parties), 42(a) (consolidation of actions). Such rules neither change plaintiffs' separate entitlements to relief nor abridge defendants' rights; they alter only how the claims are processed. For the same reason, Rule 23—at least insofar as it allows willing plaintiffs to join their separate claims against the same defendants in a class action—falls within § 2072(b)'s authorization. A class action, no less than traditional joinder (of which it is a species), merely enables a federal court to adjudicate claims of multiple parties at once, instead of in separate suits. And like traditional joinder, it leaves the parties' legal rights and duties intact and the rules of decision unchanged.

Allstate contends that the authorization of class actions is not substantively neutral: Allowing Shady Grove to sue on behalf of a class "transform[s][the] dispute over a five hundred dollar penalty into a dispute over a five million dollar penalty." Brief for Respondent 1. Allstate's aggregate liability, however, does not depend on whether the suit proceeds as a class action. Each of the 1,000-plus members of the putative class could (as Allstate acknowledges) bring a freestanding suit asserting his individual claim. It is undoubtedly true that some plaintiffs who would not bring individual suits for the relatively small sums involved will choose to join a class action. That has no bearing, however, on Allstate's or the plaintiffs' legal rights. The likelihood that some (even many) plaintiffs will be induced to sue by the availability of a class action is just the sort of "incidental effec[t]" we have long held does not violate § 2072(b), Mississippi Publishing, supra at 445, 66 S.Ct. 242.

Allstate argues that Rule 23 violates § 2072(b) because the state law it displaces, § 901(b), creates a right that the Federal Rule abridges—namely, a "substantive right . . . not to be subjected to aggregated class-action liability" in a single suit. Brief for Respondent 31. To begin with, we doubt that that is so. Nothing in the text of § 901(b) (which is to be found in New York's procedural code) confines it to claims under New York law; and of course New York has no power to alter substantive rights and duties created by other sovereigns. As we have said, the consequence of excluding certain class actions may be to cap the damages a defendant can face in a single suit, but the law itself alters only procedure. In that respect, § 901(b) is no different from a state law forbidding simple joinder. As a fallback argument, Allstate argues that even if § 901(b) is a procedural provision, it was enacted "for substantive reasons," id. at 24 (emphasis added). Its end was not to improve "the conduct of the litigation process itself" but to alter "the outcome of that process." Id. at 26.

[1444] The fundamental difficulty with both these arguments is that the substantive nature of New York's law, or its substantive purpose, makes no difference. A Federal Rule of Procedure is not valid in some jurisdictions and invalid in others—or valid in some cases and invalid in others—depending upon whether its effect is to frustrate a state substantive law (or a state procedural law enacted for substantive purposes). That could not be clearer in Sibbach:

"The petitioner says the phrase [`substantive rights' in the Rules Enabling Act] connotes more; that by its use Congress intended that in regulating procedure this Court should not deal with important and substantial rights theretofore recognized. Recognized where and by whom? The state courts are divided as to the power in the absence of statute to order a physical examination. In a number such an order is authorized by statute or rule. . . ."

"The asserted right, moreover, is no more important than many others enjoyed by litigants in District Courts sitting in the several states before the Federal Rules of Civil Procedure altered and abolished old rights or privileges and created new ones in connection with the conduct of litigation. . . . If we were to adopt the suggested criterion of the importance of the alleged right we should invite endless litigation and confusion worse confounded. The test must be whether a rule really regulates procedure.. . ." 312 U.S. at 13-14, 61 S.Ct. 422 (footnotes omitted).

Hanna unmistakably expressed the same understanding that compliance of a Federal Rule with the Enabling Act is to be assessed by consulting the Rule itself, and not its effects in individual applications:

"[T]he court has been instructed to apply the Federal Rule, and can refuse to do so only if the Advisory Committee, this Court, and Congress erred in their prima facie judgment that the Rule in question transgresses neither the terms of the Enabling Act nor constitutional restrictions." 380 U.S. at 471, 85 S.Ct. 1136.

In sum, it is not the substantive or procedural nature or purpose of the affected state law that matters, but the substantive or procedural nature of the Federal Rule. We have held since Sibbach, and reaffirmed repeatedly, that the validity of a Federal Rule depends entirely upon whether it regulates procedure. See Sibbach, supra at 14, 61 S.Ct. 422; Hanna, supra at 464, 85 S.Ct. 1136; Burlington, 480 U.S. at 8, 107 S.Ct. 967. If it does, it is authorized by § 2072 and is valid in all jurisdictions, with respect to all claims, regardless of its incidental effect upon state-created rights.

C

A few words in response to the concurrence. We understand it to accept the framework we apply—which requires first, determining whether the federal and state rules can be reconciled (because they answer different questions), and second, if they cannot, determining whether the Federal Rule runs afoul of § 2072(b). Post at 1450-1452 (STEVENS, J., concurring in part and concurring in judgment). The concurrence agrees with us that Rule 23 and § 901(b) conflict, post at 1456-1457 and departs from us only with respect to the second part of the test, i.e., whether application of the Federal Rule violates § 2072(b), post at 1451-1455. Like us, it answers no, but for a reason different from ours. Post at 1457-1460.

The concurrence would decide this case on the basis, not that Rule 23 is procedural, but that the state law it displaces is procedural, in the sense that it does not [1445] "function as a part of the State's definition of substantive rights and remedies." Post at 1448. A state procedural rule is not preempted, according to the concurrence, so long as it is "so bound up with," or "sufficiently intertwined with," a substantive state-law right or remedy "that it defines the scope of that substantive right or remedy," post at 1448, 1455.

This analysis squarely conflicts with Sibbach, which established the rule we apply. The concurrence contends that Sibbach did not rule out its approach, but that is not so. Recognizing the impracticability of a test that turns on the idiosyncrasies of state law, Sibbach adopted and applied a rule with a single criterion: whether the Federal Rule "really regulates procedure." 312 U.S. at 14, 61 S.Ct. 422.^[9] That the concurrence's approach would have yielded the same result in Sibbach proves nothing; what matters is the rule we did apply, and that rule leaves no room for special exemptions based on the function or purpose of a particular state rule.^[10] We have rejected an attempt to read into Sibbach an exception with no basis in the opinion, see Schlagenhauf, 379 U.S. at 113-114, 85 S.Ct. 234, and we see no reason to find such an implied limitation today.

In reality, the concurrence seeks not to apply Sibbach, but to overrule it (or, what is the same, to rewrite it). Its approach, the concurrence insists, gives short shrift to the statutory text forbidding the Federal Rules from "abridg[ing], enlarg[ing], or modify[ing] any substantive right," § 2072(b). See post at 1452-1453. There is something to that. It is possible to understand how it can be determined whether a Federal Rule "enlarges" substantive rights without consulting State law: If the Rule creates a substantive right, even one that duplicates some statecreated rights, it establishes a new federal right. But it is hard to understand how it can be determined whether a Federal Rule [1446] "abridges" or "modifies" substantive rights without knowing what state-created rights would obtain if the Federal Rule did not exist. Sibbach's exclusive focus on the challenged Federal Rule—driven by the very real concern that Federal Rules which vary from State to State would be chaos, see 312 U.S. at 13-14, 61 S.Ct. 422—is hard to square with § 2072(b)'s terms.^[11]

Sibbach has been settled law, however, for nearly seven decades.^[12] Setting aside any precedent requires a "special justification" beyond a bare belief that it was wrong. Patterson v. McLean Credit Union, 491 U.S. 164, 172, 109 S.Ct. 2363, 105 L.Ed.2d 132 (1989) (internal quotation marks omitted). And a party seeking to overturn a statutory precedent bears an even greater burden, since Congress remains free to correct us, ibid., and adhering to our precedent enables it do so, see, e.g., Finley v. United States, 490 U.S. 545, 556, 109 S.Ct. 2003, 104 L.Ed.2d 593 (1989); 28 U.S.C. § 1367; Exxon Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546, 558, 125 S.Ct. 2611, 162 L.Ed.2d 502 (2005). We do Congress no service by presenting it a moving target. In all events, Allstate has not even asked us to overrule Sibbach, let alone carried its burden of persuading us to do so. Cf. IBP, Inc. v. Alvarez, 546 U.S. 21, 32, 126 S.Ct. 514, 163 L.Ed.2d 288 (2005). Why we should cast aside our decades-old decision escapes us, especially since (as the concurrence explains) that would not affect the result.^[13]

[1447] The concurrence also contends that applying Sibbach and assessing whether a Federal Rule regulates substance or procedure is not always easy. See post at 1454, n. 10. Undoubtedly some hard cases will arise (though we have managed to muddle through well enough in the 69 years since Sibbach was decided). But as the concurrence acknowledges, post at 1453-1454, the basic difficulty is unavoidable: The statute itself refers to "substantive right[s]," § 2072(b), so there is no escaping the substance-procedure distinction. What is more, the concurrence's approach does nothing to diminish the difficulty, but rather magnifies it many times over. Instead of a single hard question of whether a Federal Rule regulates substance or procedure, that approach will present hundreds of hard questions, forcing federal courts to assess the substantive or procedural character of countless state rules that may conflict with a single Federal Rule.^[14] And it still does not sidestep the problem it seeks to avoid. At the end of the day, one must come face to face with the decision whether or not the state policy (with which a putatively procedural state rule may be "bound up") pertains to a "substantive right or remedy," post at 1458—that is, whether it is substance or procedure.^[15] The more one explores the alternatives to Sibbach's rule, the more its wisdom becomes apparent.

D

We must acknowledge the reality that keeping the federal-court door open to class actions that cannot proceed in state court will produce forum shopping. That is unacceptable when it comes as the consequence of judge-made rules created to fill supposed "gaps" in positive federal law. See Hanna, 380 U.S. at 471-472, 85 S.Ct. 1136. For where neither the Constitution, a treaty, nor a statute provides the rule of decision or authorizes a federal court to supply one, "state law must govern because [1448] there can be no other law." Ibid.; see Clark, Erie's Constitutional Source, 95 Cal. L.Rev. 1289, 1302, 1311 (2007). But divergence from state law, with the attendant consequence of forum shopping, is the inevitable (indeed, one might say the intended) result of a uniform system of federal procedure. Congress itself has created the possibility that the same case may follow a different course if filed in federal instead of state court. Cf. Hanna, 380 U.S. at 472-473, 85 S.Ct. 1136. The short of the matter is that a Federal Rule governing procedure is valid whether or not it alters the outcome of the case in a way that induces forum shopping. To hold otherwise would be to "disembowel either the Constitution's grant of power over federal procedure" or Congress's exercise of it. Id. at 473-474, 85 S.Ct. 1136.

* * *

The judgment of the Court of Appeals is reversed, and the case is remanded for further proceedings.

It is so ordered.

Justice STEVENS, concurring in part and concurring in the judgment.

The New York law at issue, N.Y. Civ. Prac. Law Ann. (CPLR) § 901(b) (West 2006), is a procedural rule that is not part of New York's substantive law. Accordingly, I agree with Justice SCALIA that Federal Rule of Civil Procedure 23 must apply in this case and join Parts I and II-A of the Court's opinion. But I also agree with Justice GINSBURG that there are some state procedural rules that federal courts must apply in diversity cases because they function as a part of the State's definition of substantive rights and remedies.

I

It is a long-recognized principle that federal courts sitting in diversity "apply state substantive law and federal procedural law." Hanna v. Plumer, 380 U.S. 460, 465, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965).^[16] This principle is governed by a statutory framework, and the way that it is administered varies depending upon whether there is a federal rule addressed to the matter. See id. at 469-472, 85 S.Ct. 1136. If no federal rule applies, a federal court must follow the Rules of Decision Act, 28 U.S.C. § 1652, and make the "relatively unguided Erie choice,"^[17]Hanna, 380 U.S. at 471, 85 S.Ct. 1136, to determine whether the state law is the "rule of decision." But when a situation is covered by a federal rule, the Rules of Decision Act inquiry by its own terms does not apply. See § 1652; Hanna, 380 U.S. at 471, 85 S.Ct. 1136. Instead, the Rules Enabling Act (Enabling Act) controls. See 28 U.S.C. § 2072.

That does not mean, however, that the federal rule always governs. Congress has provided for a system of uniform federal rules, see ibid., under which federal courts sitting in diversity operate as "an independent system for administering justice to litigants who properly invoke its jurisdiction," Byrd v. Blue Ridge Rural Elec. Cooperative, Inc., 356 U.S. 525, 537, 78 S.Ct. 893, 2 L.Ed.2d 953 (1958), and not [1449] as state-court clones that assume all aspects of state tribunals but are managed by Article III judges. See Hanna, 380 U.S. at 473-474, 85 S.Ct. 1136. But while Congress may have the constitutional power to prescribe procedural rules that interfere with state substantive law in any number of respects, that is not what Congress has done. Instead, it has provided in the Enabling Act that although "[t]he Supreme Court" may "prescribe general rules of practice and procedure," § 2072(a), those rules "shall not abridge, enlarge or modify any substantive right," § 2072(b). Therefore, "[w]hen a situation is covered by one of the Federal Rules,. . . the court has been instructed to apply the Federal Rule" unless doing so would violate the Act or the Constitution. Hanna, 380 U.S. at 471, 85 S.Ct. 1136.

Although the Enabling Act and the Rules of Decision Act "say, roughly, that federal courts are to apply state `substantive' law and federal `procedural' law," the inquiries are not the same. Ibid.; see also id. at 469-470, 85 S.Ct. 1136. The Enabling Act does not invite federal courts to engage in the "relatively unguided Erie choice," id. at 471, 85 S.Ct. 1136, but instead instructs only that federal rules cannot "abridge, enlarge or modify any substantive right," § 2072(b). The Enabling Act's limitation does not mean that federal rules cannot displace state policy judgments; it means only that federal rules cannot displace a State's definition of its own rights or remedies. See Sibbach v. Wilson & Co., 312 U.S. 1, 13-14, 61 S.Ct. 422, 85 L.Ed. 479 (1941) (reasoning that "the phrase `substantive rights'" embraces only those state rights that are sought to be enforced in the judicial proceedings).

Congress has thus struck a balance: "[H]ousekeeping rules for federal courts" will generally apply in diversity cases, notwithstanding that some federal rules "will inevitably differ" from state rules. Hanna, 380 U.S. at 473, 85 S.Ct. 1136. But not every federal "rul[e] of practice or procedure," § 2072(a), will displace state law. To the contrary, federal rules must be interpreted with some degree of "sensitivity to important state interests and regulatory policies," Gasperini v. Center for Humanities, Inc., 518 U.S. 415, 427, n. 7, 116 S.Ct. 2211, 135 L.Ed.2d 659 (1996), and applied to diversity cases against the background of Congress' command that such rules not alter substantive rights and with consideration of "the degree to which the Rule makes the character and result of the federal litigation stray from the course it would follow in state courts," Hanna, 380 U.S. at 473, 85 S.Ct. 1136. This can be a tricky balance to implement.^[18]

It is important to observe that the balance Congress has struck turns, in part, on the nature of the state law that is being displaced by a federal rule. And in my view, the application of that balance does not necessarily turn on whether the state law at issue takes the form of what is traditionally described as substantive or procedural. Rather, it turns on whether the state law actually is part of a State's framework of substantive rights or remedies. See § 2072(b); cf. Hanna, 380 U.S. at 471, 85 S.Ct. 1136 ("The line between `substance' and `procedure' shifts as the legal context changes"); Guaranty Trust Co. v. York, 326 U.S. 99, 108, 65 S.Ct. 1464, 89 L.Ed. 2079 (1945) (noting that the words "`substance'" and "`procedure'" "[e]ach impl[y] different variables depending [1450] upon the particular problem for which [they] are used").

Applying this balance, therefore, requires careful interpretation of the state and federal provisions at issue. "The line between procedural and substantive law is hazy," Erie R. Co. v. Tompkins, 304 U.S. 64, 92, 58 S.Ct. 817, 82 L.Ed. 1188 (1938) (Reed, J., concurring), and matters of procedure and matters of substance are not "mutually exclusive categories with easily ascertainable contents," Sibbach, 312 U.S. at 17, 61 S.Ct. 422 (Frankfurter, J., dissenting). Rather, "[r]ules which lawyers call procedural do not always exhaust their effect by regulating procedure," Cohen v. Beneficial Industrial Loan Corp., 337 U.S. 541, 555, 69 S.Ct. 1221, 93 L.Ed. 1528 (1949), and in some situations, "procedure and substance are so interwoven that rational separation becomes well-nigh impossible," id. at 559, 69 S.Ct. 1221 (Rutledge, J., dissenting). A "state procedural rule, though undeniably `procedural' in the ordinary sense of the term," may exist "to influence substantive outcomes," S.A. Healy Co. v. Milwaukee Metropolitan Sewerage Dist., 60 F.3d 305, 310 (C.A.7 1995) (Posner, J.), and may in some instances become so bound up with the state-created right or remedy that it defines the scope of that substantive right or remedy. Such laws, for example, may be seemingly procedural rules that make it significantly more difficult to bring or to prove a claim, thus serving to limit the scope of that claim. See, e.g., Cohen, 337 U.S. at 555, 69 S.Ct. 1221 (state "procedure" that required plaintiffs to post bond before suing); Guaranty Trust Co., 326 U.S. 99, 65 S.Ct. 1464, 89 L.Ed. 2079 (state statute of limitations).^[19] Such "procedural rules" may also define the amount of recovery. See, e.g., Gasperini, 518 U.S. at 427, 116 S.Ct. 2211 (state procedure for examining jury verdicts as means of capping the available remedy); Moore § 124.07[3][a] (listing examples of federal courts' applying state laws that affect the amount of a judgment).

In our federalist system, Congress has not mandated that federal courts dictate to state legislatures the form that their substantive law must take. And were federal courts to ignore those portions of substantive state law that operate as procedural devices, it could in many instances limit the ways that sovereign States may define their rights and remedies. When a State chooses to use a traditionally procedural vehicle as a means of defining the scope of substantive rights or remedies, federal courts must recognize and respect that choice. Cf. Ragan v. Merchants Transfer & Warehouse Co., 337 U.S. 530, 533, 69 S.Ct. 1233, 93 L.Ed. 1520 (1949) ("Since th[e] cause of action is created by local law, the measure of it is to be found only in local law . . . . Where local law qualifies or abridges it, the federal court must follow suit").

II

When both a federal rule and a state law appear to govern a question before a federal court sitting in diversity, our precedents have set out a two-step framework for federal courts to negotiate this thorny area. At both steps of the inquiry, there is a critical question about what the state law and the federal rule mean.

[1451] The court must first determine whether the scope of the federal rule is "`sufficiently broad'" to "`control the issue'" before the court, "thereby leaving no room for the operation" of seemingly conflicting state law. See Burlington Northern R. Co. v. Woods, 480 U.S. 1, 4-5, 107 S.Ct. 967, 94 L.Ed.2d 1 (1987); Walker v. Armco Steel Corp., 446 U.S. 740, 749-750, and n. 9, 100 S.Ct. 1978, 64 L.Ed.2d 659 (1980). If the federal rule does not apply or can operate alongside the state rule, then there is no "Ac[t] of Congress" governing that particular question, 28 U.S.C. § 1652, and the court must engage in the traditional Rules of Decision Act inquiry under Erie and its progeny. In some instances, the "plain meaning" of a federal rule will not come into "`direct collision'" with the state law, and both can operate. Walker, 446 U.S. at 750, n. 9, 749, 100 S.Ct. 1978. In other instances, the rule "when fairly construed," Burlington Northern R. Co., 480 U.S. at 4, 107 S.Ct. 967, with "sensitivity to important state interests and regulatory policies," Gasperini, 518 U.S. at 427, n. 7, 116 S.Ct. 2211, will not collide with the state law.^[20]

If, on the other hand, the federal rule is "sufficiently broad to control the issue before the Court," such that there is a "direct collision," Walker, 446 U.S. at 749-750, 100 S.Ct. 1978, the court must decide whether application of the federal rule "represents a valid exercise" of the "rulemaking authority . . . bestowed on this Court by the Rules Enabling Act." Burlington Northern R. Co., 480 U.S. at 5, 107 S.Ct. 967; see also Gasperini, 518 U.S. at 427, n. 7, 116 S.Ct. 2211; Hanna, 380 U.S. at 471-474, 85 S.Ct. 1136. That Act requires, inter alia, that federal rules "not abridge, enlarge or modify any substantive right." 28 U.S.C. § 2072(b) (emphasis added). Unlike Justice SCALIA, I believe that an application of a federal rule that effectively abridges, enlarges, or modifies a state-created right or remedy violates this command. Congress may have the constitutional power "to supplant state law" with rules that are "rationally capable of classification as procedure," ante at 1442 (internal quotation marks omitted), but we should generally presume that it has not done so. Cf. Wyeth v. Levine, 555 U.S. ___, ___, 129 S.Ct. 1187, 1194-95, 173 L.Ed.2d 51 (2009) (observing that "we start with the assumption" that a federal statute does not displace a State's law "unless that was the clear and manifest purpose of Congress" (internal quotation marks omitted)). Indeed, the mandate that federal rules "shall not abridge, enlarge or modify any substantive right" evinces the opposite intent, as does Congress' decision to delegate the creation of rules to this Court rather than to a political branch, see 19 Charles Alan Wright, Arthur R. Miller, & Edward H. Cooper, Federal Practice and Procedure § 4509, p. 265 (2d ed.1996) (hereinafter Wright).

[1452] Thus, the second step of the inquiry may well bleed back into the first. When a federal rule appears to abridge, enlarge, or modify a substantive right, federal courts must consider whether the rule can reasonably be interpreted to avoid that impermissible result. See, e.g., Semtek Int'l Inc. v. Lockheed Martin Corp., 531 U.S. 497, 503, 121 S.Ct. 1021, 149 L.Ed.2d 32 (2001) (avoiding an interpretation of Federal Rule of Civil Procedure 41(b) that "would arguably violate the jurisdictional limitation of the Rules Enabling Act" contained in § 2072(b)).^[21] And when such a "saving" construction is not possible and the rule would violate the Enabling Act, federal courts cannot apply the rule. See 28 U.S.C. § 2072(b) (mandating that federal rules "shall not" alter "any substantive right" (emphasis added)); Hanna, 380 U.S. at 473, 85 S.Ct. 1136 ("[A] court, in measuring a Federal Rule against the standards contained in the Enabling Act. . . need not wholly blind itself to the degree to which the Rule makes the character and result of the federal litigation stray from the course it would follow in state courts"); see also Semtek Int'l Inc., 531 U.S. at 503-504, 121 S.Ct. 1021 (noting that if state law granted a particular right, "the federal court's extinguishment of that right . . . would seem to violate [§ 2072(b)]"); cf. Statement of Justices Black and Douglas, 374 U.S. 865, 870 (1963) (observing that federal rules "as applied in given situations might have to be declared invalid"). A federal rule, therefore, cannot govern a particular case in which the rule would displace a state law that is procedural in the ordinary use of the term but is so intertwined with a state right or remedy that it functions to define the scope of the state-created right. And absent a governing federal rule, a federal court must engage in the traditional Rules of Decision Act inquiry, under the Erie line of cases. This application of the Enabling Act shows "sensitivity to important state interests," post at 1463, and "regulatory policies," post at 1460, but it does so as Congress authorized, by ensuring that federal rules that ordinarily "prescribe general rules of practice and procedure," § 2072(a), do "not abridge, enlarge or modify any substantive right," § 2072(b).

Justice SCALIA believes that the sole Enabling Act question is whether the federal rule "really regulates procedure," ante at 1442, 1444, 1445, 1446, n. 13 (plurality opinion) (internal quotation marks omitted), which means, apparently, whether it regulates "the manner and the means by which the litigants' rights are enforced," ante at 1442 (internal quotation marks omitted). I respectfully disagree.^[22] This interpretation of the Enabling Act is consonant with the Act's first limitation to "general rules of practice and procedure," § 2072(a). But it ignores the second limitation [1453] that such rules also "not abridge, enlarge or modify any substantive right," § 2072(b) (emphasis added),^[23] and in so doing ignores the balance that Congress struck between uniform rules of federal procedure and respect for a State's construction of its own rights and remedies. It also ignores the separation-of-powers presumption, see Wright § 4509, at 265, and federalism presumption, see Wyeth, 555 U.S., at ___, 129 S.Ct. at 1194-95, that counsel against judicially created rules displacing state substantive law.^[24]

Although the plurality appears to agree with much of my interpretation of § 2072, see ante at 1445-1446, it nonetheless rejects that approach for two reasons, both of which are mistaken. First, Justice SCALIA worries that if federal courts inquire into the effect of federal rules on state law, it will enmesh federal courts in difficult determinations about whether application [1454] of a given rule would displace a state determination about substantive rights. See ante at 1443-1444, 1447-1448, and nn. 14, 15. I do not see why an Enabling Act inquiry that looks to state law necessarily is more taxing than Justice SCALIA's.^[25] But in any event, that inquiry is what the Enabling Act requires: While it may not be easy to decide what is actually a "substantive right," "the designations substantive and procedural become important, for the Enabling Act has made them so." Ely 723; see also Wright § 4509, at 266. The question, therefore, is not what rule we think would be easiest on federal courts. The question is what rule Congress established. Although, Justice SCALIA may generally prefer easily administrable, bright-line rules, his preference does not give us license to adopt a second-best interpretation of the Rules Enabling Act. Courts cannot ignore text and context in the service of simplicity.

Second, the plurality argues that its interpretation of the Enabling Act is dictated by this Court's decision in Sibbach, which applied a Federal Rule about when parties must submit to medical examinations. But the plurality misreads that opinion. As Justice Harlan observed in Hanna, "shorthand formulations which have appeared in earlier opinions are prone to carry untoward results that frequently arise from oversimplification." 380 U.S. at 475, 85 S.Ct. 1136 (concurring opinion). To understand Sibbach, it is first necessary to understand the issue that was before the Court. The petitioner raised only the facial question whether "Rules 35 and 37 [of the Federal Rules of Civil Procedure] are . . . within the mandate of Congress to this court" and not the specific question of "the obligation of federal courts to apply the substantive law of a state."^[26] 312 U.S. at 9, 61 S.Ct. 422. The Court, therefore, had no occasion to consider whether the particular application of the Federal Rules in question would offend the Enabling Act.^[27]

[1455] Nor, in Sibbach, was any further analysis necessary to the resolution of the case because the matter at issue, requiring medical exams for litigants, did not pertain to "substantive rights" under the Enabling Act. Although most state rules bearing on the litigation process are adopted for some policy reason, few seemingly "procedural" rules define the scope of a substantive right or remedy. The matter at issue in Sibbach reflected competing federal and state judgments about privacy interests. Those privacy concerns may have been weighty and in some sense substantive; but they did not pertain to the scope of any state right or remedy at issue in the litigation. Thus, in response to the petitioner's argument in Sibbach that "substantive rights" include not only "rights sought to be adjudicated by the litigants" but also "general principle[s]" or "question[s] of public policy that the legislature is able to pass upon," id. at 2-3, 61 S.Ct. 422, we held that "the phrase `substantive rights'" embraces only state rights, such as the tort law in that case, that are sought to be enforced in the judicial proceedings. Id. at 13-14, 61 S.Ct. 422. If the Federal Rule had in fact displaced a state rule that was sufficiently intertwined with a state right or remedy, then perhaps the Enabling Act analysis would have been different.^[28] Our subsequent cases are not to the contrary.^[29]

III

Justice GINSBURG views the basic issue in this case as whether and how to [1456] apply a federal rule that dictates an answer to a traditionally procedural question (whether to join plaintiffs together as a class), when a state law that "defines the dimensions" of a state-created claim dictates the opposite answer. Post at 1458. As explained above, I readily acknowledge that if a federal rule displaces a state rule that is "`procedural' in the ordinary sense of the term," S.A. Healy Co., 60 F.3d at 310, but sufficiently interwoven with the scope of a substantive right or remedy, there would be an Enabling Act problem, and the federal rule would have to give way. In my view, however, this is not such a case.

Rule 23 Controls Class Certification

When the District Court in the case before us was asked to certify a class action, Federal Rule of Civil Procedure 23 squarely governed the determination whether the court should do so. That is the explicit function of Rule 23. Rule 23, therefore, must apply unless its application would abridge, enlarge, or modify New York rights or remedies.

Notwithstanding the plain language of Rule 23, I understand the dissent to find that Rule 23 does not govern the question of class certification in this matter because New York has made a substantive judgment that such a class should not be certified, as a means of proscribing damages. Although, as discussed infra at 1469-1471, I do not accept the dissent's view of § 901(b), I also do not see how the dissent's interpretation of Rule 23 follows from that view.^[30] I agree with JUSTICE GINSBURG that courts should "avoi[d] immoderate interpretations of the Federal Rules that would trench on state prerogatives," post at 1461-1462, and should in some instances "interpre[t] the federal rules to avoid conflict with important state regulatory policies," post at 1462 (internal quotation marks omitted). But that is not what the dissent has done. Simply because a rule should be read in light of federalism concerns, it does not follow that courts may rewrite the rule.

At bottom, the dissent's interpretation of Rule 23 seems to be that Rule 23 covers only those cases in which its application would create no Erie problem. The dissent would apply the Rules of Decision Act inquiry under Erie even to cases in which there is a governing federal rule, and thus the Act, by its own terms, does not apply. But "[w]hen a situation is covered by one of the Federal Rules, the question facing the court is a far cry from the typical, [1457] relatively unguided Erie choice." Hanna, 380 U.S. at 471, 85 S.Ct. 1136. The question is only whether the Enabling Act is satisfied. Although it reflects a laudable concern to protect "state regulatory policies," post at 1462 (internal quotation marks omitted), Justice GINSBURG's approach would, in my view, work an end run around Congress' system of uniform federal rules, see 28 U.S.C. § 2072, and our decision in Hanna. Federal courts can and should interpret federal rules with sensitivity to "state prerogatives," post at 1462; but even when "state interests . . . warrant our respectful consideration," post at 1464, federal courts cannot rewrite the rules. If my dissenting colleagues feel strongly that § 901(b) is substantive and that class certification should be denied, then they should argue within the Enabling Act's framework. Otherwise, "the Federal Rule applies regardless of contrary state law." Gasperini, 518 U.S. at 427, n. 7, 116 S.Ct. 2211; accord, Hanna, 380 U.S. at 471, 85 S.Ct. 1136.

Applying Rule 23 Does Not Violate the Enabling Act

As I have explained, in considering whether to certify a class action such as this one, a federal court must inquire whether doing so would abridge, enlarge, or modify New York's rights or remedies, and thereby violate the Enabling Act. This inquiry is not always a simple one because "[i]t is difficult to conceive of any rule of procedure that cannot have a significant effect on the outcome of a case," Wright § 4508, at 232-233, and almost "any rule can be said to have . . . `substantive effects,' affecting society's distribution of risks and rewards," Ely 724, n. 170. Faced with a federal rule that dictates an answer to a traditionally procedural question and that displaces a state rule, one can often argue that the state rule was really some part of the State's definition of its rights or remedies.

In my view, however, the bar for finding an Enabling Act problem is a high one. The mere fact that a state law is designed as a procedural rule suggests it reflects a judgment about how state courts ought to operate and not a judgment about the scope of state-created rights and remedies. And for the purposes of operating a federal court system, there are costs involved in attempting to discover the true nature of a state procedural rule and allowing such a rule to operate alongside a federal rule that appears to govern the same question. The mere possibility that a federal rule would alter a state-created right is not sufficient. There must be little doubt.

The text of CPLR § 901(b) expressly and unambiguously applies not only to claims based on New York law but also to claims based on federal law or the law of any other State. And there is no interpretation from New York courts to the contrary. It is therefore hard to see how § 901(b) could be understood as a rule that, though procedural in form, serves the function of defining New York's rights or remedies. This is all the more apparent because lawsuits under New York law could be joined in federal class actions well before New York passed § 901(b) in 1975, and New York had done nothing to prevent that. It is true, as the dissent points out, that there is a limited amount of legislative history that can be read to suggest that the New York officials who supported § 901(b) wished to create a "limitation" on New York's "statutory damages." Post at 1464. But, as Justice SCALIA notes, that is not the law that New York adopted.^[31] [1458] See ante at 1439-1440 (opinion of the Court).

The legislative history, moreover, does not clearly describe a judgment that § 901(b) would operate as a limitation on New York's statutory damages. In evaluating that legislative history, it is necessary to distinguish between procedural rules adopted for some policy reason and seemingly procedural rules that are intimately bound up in the scope of a substantive right or remedy. Although almost every rule is adopted for some reason and has some effect on the outcome of litigation, not every state rule "defines the dimensions of [a] claim itself," post at 1466. New York clearly crafted § 901(b) with the intent that only certain lawsuits—those for which there were not statutory penalties—could be joined in class actions in New York courts. That decision reflects a policy judgment about which lawsuits should proceed in New York courts in a class form and which should not. As Justice GINSBURG carefully outlines, see post at 1464-1465, § 901(b) was "apparently" adopted in response to fears that the class-action procedure, applied to statutory penalties, would lead to "annihilating punishment of the defendant." V. Alexander, Practice Commentaries, C901:11, reprinted in 7B McKinney's Consolidated Laws of New York Ann., p. 104 (2006) (internal quotation marks omitted); see also Sperry v. Crompton Corp., 8 N.Y.3d 204, 211, 831 N.Y.S.2d 760, 863 N.E.2d 1012, 1015 (2007). But statements such as these are not particularly strong evidence that § 901(b) serves to define who can obtain a statutory penalty or that certifying such a class would enlarge New York's remedy. Any device that makes litigation easier makes it easier for plaintiffs to recover damages.

In addition to the fear of excessive recoveries, some opponents of a broad class-action device "argued that there was no need to permit class actions in order to encourage litigation . . . when statutory penalties . . . provided an aggrieved party with a sufficient economic incentive to pursue a claim." Id., at 211, 831 N.Y.S.2d 760, 863 N.E.2d, at 1015 (emphasis added). But those opponents may have felt merely that, for any number of reasons, New York courts should not conduct trials in the class format when that format is unnecessary [1459] to motivate litigation.^[32] Justice GINSBURG asserts that this could not be true because "suits seeking statutory damages are arguably best suited to the class device because individual proof of actual damages is unnecessary." Post at 1464-1465. But some people believe that class actions are inefficient or at least unfair, insofar as they join together slightly disparate claims or force courts to adjudicate unwieldy lawsuits. It is not for us to dismiss the possibility that New York legislators shared in those beliefs and thus wanted to exclude the class vehicle when it appeared to be unnecessary.

The legislative history of § 901 thus reveals a classically procedural calibration of making it easier to litigate claims in New York courts (under any source of law) only when it is necessary to do so, and not making it too easy when the class tool is not required. This is the same sort of calculation that might go into setting filing fees or deadlines for briefs. There is of course a difference of degree between those examples and class certification, but not a difference of kind; the class vehicle may have a greater practical effect on who brings lawsuits than do low filing fees, but that does not transform it into a damages "proscription," post at 1466, n. 6, 1471, or "limitation," post at 1463, n. 2, 1464, 1464-1465, 1466, 1473.^[33]

The difference of degree is relevant to the forum shopping considerations that are part of the Rules of Decision Act or Erie inquiry. If the applicable federal rule did not govern the particular question at issue (or could be fairly read not to do so), then those considerations would matter, for precisely the reasons given by the dissent. See post at 1469-1473. But that is not this case. As the Court explained in Hanna, it is an "incorrect assumption that the rule of Erie R. Co. v. Tompkins constitutes the appropriate test of . . . the applicability of a Federal Rule of Civil Procedure." 380 U.S. at 469-470, 85 S.Ct. 1136. "It is true that both the Enabling Act and the Erie rule say, roughly, that federal courts are to apply state `substantive' law and federal `procedural' law," but the tests are different and reflect the fact that "they were designed to control very different sorts of decisions." Id. at 471, 85 S.Ct. 1136.

Because Rule 23 governs class certification, the only decision is whether certifying a class in this diversity case would "abridge, enlarge or modify" New York's substantive rights or remedies. § 2072(b). Although one can argue that class certification would enlarge New York's "limited" damages remedy, see post at 1463, n. 2, 1464, 1464-1465, 1466, 1473, such arguments rest on extensive speculation about what the New York Legislature had in mind when it created § 901(b). But given that there are two plausible competing narratives, it seems obvious to me that we [1460] should respect the plain textual reading of § 901(b), a rule in New York's procedural code about when to certify class actions brought under any source of law, and respect Congress' decision that Rule 23 governs class certification in federal courts. In order to displace a federal rule, there must be more than just a possibility that the state rule is different than it appears.

Accordingly, I concur in part and concur in the judgment.

Justice GINSBURG, with whom Justice KENNEDY, Justice BREYER, and Justice ALITO join, dissenting.

The Court today approves Shady Grove's attempt to transform a $500 case into a $5,000,000 award, although the State creating the right to recover has proscribed this alchemy. If Shady Grove had filed suit in New York state court, the 2% interest payment authorized by New York Ins. Law Ann. § 5106(a) (West 2009) as a penalty for overdue benefits would, by Shady Grove's own measure, amount to no more than $500. By instead filing in federal court based on the parties' diverse citizenship and requesting class certification, Shady Grove hopes to recover, for the class, statutory damages of more than $5,000,000. The New York Legislature has barred this remedy, instructing that, unless specifically permitted, "an action to recover a penalty, or minimum measure of recovery created or imposed by statute may not be maintained as a class action." N.Y. Civ. Prac. Law Ann. (CPLR) § 901(b) (West 2006). The Court nevertheless holds that Federal Rule of Civil Procedure 23, which prescribes procedures for the conduct of class actions in federal courts, preempts the application of § 901(b) in diversity suits.

The Court reads Rule 23 relentlessly to override New York's restriction on the availability of statutory damages. Our decisions, however, caution us to ask, before undermining state legislation: Is this conflict really necessary? Cf. Traynor, Is This Conflict Really Necessary? 37 Tex. L.Rev. 657 (1959). Had the Court engaged in that inquiry, it would not have read Rule 23 to collide with New York's legitimate interest in keeping certain monetary awards reasonably bounded. I would continue to interpret Federal Rules with awareness of, and sensitivity to, important state regulatory policies. Because today's judgment radically departs from that course, I dissent.

I

A

"Under the Erie doctrine," it is long settled, "federal courts sitting in diversity apply state substantive law and federal procedural law." Gasperini v. Center for Humanities, Inc., 518 U.S. 415, 427, 116 S.Ct. 2211, 135 L.Ed.2d 659 (1996); see Erie R. Co. v. Tompkins, 304 U.S. 64, 58 S.Ct. 817, 82 L.Ed. 1188 (1938). Justice Harlan aptly conveyed the importance of the doctrine; he described Erie as "one of the modern cornerstones of our federalism, expressing policies that profoundly touch the allocation of judicial power between the state and federal systems." Hanna v. Plumer, 380 U.S. 460, 474, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965) (concurring opinion). Although we have found Erie's application "sometimes [to be] a challenging endeavor," Gasperini, 518 U.S. at 427, 116 S.Ct. 2211, two federal statutes mark our way.

The first, the Rules of Decision Act,^[34] prohibits federal courts from generating [1461] substantive law in diversity actions. See Erie, 304 U.S. at 78, 58 S.Ct. 817. Originally enacted as part of the Judiciary Act of 1789, this restraint serves a policy of prime importance to our federal system. We have therefore applied the Act "with an eye alert to ... avoiding disregard of State law." Guaranty Trust Co. v. York, 326 U.S. 99, 110, 65 S.Ct. 1464, 89 L.Ed. 2079 (1945).

The second, the Rules Enabling Act, enacted in 1934, authorizes us to "prescribe general rules of practice and procedure" for the federal courts, but with a crucial restriction: "Such rules shall not abridge, enlarge or modify any substantive right." 28 U.S.C. § 2072. Pursuant to this statute, we have adopted the Federal Rules of Civil Procedure. In interpreting the scope of the Rules, including, in particular, Rule 23, we have been mindful of the limits on our authority. See, e.g., Ortiz v. Fibreboard Corp., 527 U.S. 815, 845, 119 S.Ct. 2295, 144 L.Ed.2d 715 (1999) (The Rules Enabling Act counsels against "adventurous application" of Rule 23; any tension with the Act "is best kept within tolerable limits."); Amchem Products, Inc. v. Windsor, 521 U.S. 591, 612-613, 117 S.Ct. 2231, 138 L.Ed.2d 689 (1997). See also Semtek Int'l Inc. v. Lockheed Martin Corp., 531 U.S. 497, 503-504, 121 S.Ct. 1021, 149 L.Ed.2d 32 (2001).

If a Federal Rule controls an issue and directly conflicts with state law, the Rule, so long as it is consonant with the Rules Enabling Act, applies in diversity suits. See Hanna, 380 U.S. at 469-474, 85 S.Ct. 1136. If, however, no Federal Rule or statute governs the issue, the Rules of Decision Act, as interpreted in Erie, controls. That Act directs federal courts, in diversity cases, to apply state law when failure to do so would invite forum-shopping and yield markedly disparate litigation outcomes. See Gasperini, 518 U.S. at 428, 116 S.Ct. 2211; Hanna, 380 U.S. at 468, 85 S.Ct. 1136. Recognizing that the Rules of Decision Act and the Rules Enabling Act simultaneously frame and inform the Erie analysis, we have endeavored in diversity suits to remain safely within the bounds of both congressional directives.

B

In our prior decisions in point, many of them not mentioned in the Court's opinion, we have avoided immoderate interpretations of the Federal Rules that would trench on state prerogatives without serving any countervailing federal interest. "Application of the Hanna analysis," we have said, "is premised on a `direct collision' between the Federal Rule and the state law." Walker v. Armco Steel Corp., 446 U.S. 740, 749-750, 100 S.Ct. 1978, 64 L.Ed.2d 659 (1980) (quoting Hanna, 380 U.S. at 472, 85 S.Ct. 1136). To displace state law, a Federal Rule, "when fairly construed," must be "`sufficiently broad'" so as "to `control the issue' before the court, thereby leaving no room for the operation of that law." Burlington Northern R. Co. v. Woods, 480 U.S. 1, 4-5, 107 S.Ct. 967, 94 L.Ed.2d 1 (1987) (quoting Walker, 446 U.S. at 749-750, and n. 9, 100 S.Ct. 1978; emphasis added); cf. Stewart Organization, Inc. v. Ricoh Corp., 487 U.S. 22, 37-38, 108 S.Ct. 2239, 101 L.Ed.2d 22 (1988) (SCALIA, J., dissenting) ("[I]n deciding whether a federal ... Rule of Procedure encompasses a particular issue, a broad reading that would create significant disuniformity between state and federal courts should be avoided if the text permits.").

[1462] In pre-Hanna decisions, the Court vigilantly read the Federal Rules to avoid conflict with state laws. In Palmer v. Hoffman, 318 U.S. 109, 117, 63 S.Ct. 477, 87 L.Ed. 645 (1943), for example, the Court read Federal Rule 8(c), which lists affirmative defenses, to control only the manner of pleading the listed defenses in diversity cases; as to the burden of proof in such cases, Palmer held, state law controls.

Six years later, in Ragan v. Merchants Transfer & Warehouse Co., 337 U.S. 530, 69 S.Ct. 1233, 93 L.Ed. 1520 (1949), the Court ruled that state law determines when a diversity suit commences for purposes of tolling the state limitations period. Although Federal Rule 3 specified that "[a] civil action is commenced by filing a complaint with the court," we held that the Rule did not displace a state law that tied an action's commencement to service of the summons. Id. at 531-533, 69 S.Ct. 1233. The "cause of action [wa]s created by local law," the Court explained, therefore "the measure of it [wa]s to be found only in local law." Id. at 533, 69 S.Ct. 1233.

Similarly in Cohen v. Beneficial Industrial Loan Corp., 337 U.S. 541, 69 S.Ct. 1221, 93 L.Ed. 1528 (1949), the Court held applicable in a diversity action a state statute requiring plaintiffs, as a prerequisite to pursuit of a stockholder's derivative action, to post a bond as security for costs. At the time of the litigation, Rule 23, now Rule 23.1, addressed a plaintiff's institution of a derivative action in federal court. Although the Federal Rule specified prerequisites to a stockholder's maintenance of a derivative action, the Court found no conflict between the Rule and the state statute in question; the requirements of both could be enforced, the Court observed. See id., at 556, 69 S.Ct. 1221. Burdensome as the security-for-costs requirement may be, Cohen made plain, suitors could not escape the upfront outlay by resorting to the federal court's diversity jurisdiction.

In all of these cases, the Court stated in Hanna, "the scope of the Federal Rule was not as broad as the losing party urged, and therefore, there being no Federal Rule which covered the point in dispute, Erie commanded the enforcement of state law." 380 U.S. at 470, 85 S.Ct. 1136. In Hanna itself, the Court found the clash "unavoidable," ibid.; the petitioner had effected service of process as prescribed by Federal Rule 4(d)(1), but that "how-to" method did not satisfy the special Massachusetts law applicable to service on an executor or administrator. Even as it rejected the Massachusetts prescription in favor of the federal procedure, however, "[t]he majority in Hanna recognized ... that federal rules ... must be interpreted by the courts applying them, and that the process of interpretation can and should reflect an awareness of legitimate state interests." R. Fallon, J. Manning, D. Meltzer, & D. Shapiro, Hart and Wechsler's The Federal Courts and the Federal System 593 (6th ed.2009) (hereinafter Hart & Wechsler).

Following Hanna, we continued to "interpre[t] the federal rules to avoid conflict with important state regulatory policies." Hart & Wechsler 593. In Walker, the Court took up the question whether Ragan should be overruled; we held, once again, that Federal Rule 3 does not directly conflict with state rules governing the time when an action commences for purposes of tolling a limitations period. 446 U.S. at 749-752, 100 S.Ct. 1978. Rule 3, we said, addresses only "the date from which various timing requirements of the Federal Rules begin to run," id. at 751, 100 S.Ct. 1978, and does not "purpor[t] to displace state tolling rules," id. at 750-751, 100 S.Ct. 1978. Significant state policy interests would be frustrated, we observed, [1463] were we to read Rule 3 as superseding the state rule, which required actual service on the defendant to stop the clock on the statute of limitations. Id. at 750-752, 100 S.Ct. 1978.

We were similarly attentive to a State's regulatory policy in Gasperini. That diversity case concerned the standard for determining when the large size of a jury verdict warrants a new trial. Federal and state courts alike had generally employed a "shock the conscience" test in reviewing jury awards for excessiveness. See 518 U.S. at 422, 116 S.Ct. 2211. Federal courts did so pursuant to Federal Rule 59(a) which, as worded at the time of Gasperini, instructed that a trial court could grant a new trial "for any of the reasons for which new trials have heretofore been granted in actions at law in the courts of the United States." Fed. Rule Civ. Proc. 59(a) (West 1995). In an effort to provide greater control, New York prescribed procedures under which jury verdicts would be examined to determine whether they "deviate[d] materially from what would be reasonable compensation." See Gasperini, 518 U.S. at 423-425, 116 S.Ct. 2211 (quoting CPLR § 5501(c)). This Court held that Rule 59(a) did not inhibit federal-court accommodation of New York's invigorated test.

Most recently, in Semtek, we addressed the claim-preclusive effect of a federal-court judgment dismissing a diversity action on the basis of a California statute of limitations. The case came to us after the same plaintiff renewed the same fray against the same defendant in a Maryland state court. (Plaintiff chose Maryland because that State's limitations period had not yet run.) We held that Federal Rule 41(b), which provided that an involuntary dismissal "operate[d] as an adjudication on the merits," did not bar maintenance of the renewed action in Maryland. To hold that Rule 41(b) precluded the Maryland courts from entertaining the case, we said, "would arguably violate the jurisdictional limitation of the Rules Enabling Act," 531 U.S. at 503, 121 S.Ct. 1021, and "would in many cases violate [Erie's] federalism principle," id. at 504, 121 S.Ct. 1021.

In sum, both before and after Hanna, the above-described decisions show, federal courts have been cautioned by this Court to "interpre[t] the Federal Rules... with sensitivity to important state interests," Gasperini, 518 U.S. at 427, n. 7, 116 S.Ct. 2211, and a will "to avoid conflict with important state regulatory policies," id. at 438, n. 22, 116 S.Ct. 2211 (internal quotation marks omitted).^[35] The Court [1464] veers away from that approach—and conspicuously, its most recent reiteration in Gasperini, ante at 1441, n. 7—in favor of a mechanical reading of Federal Rules, insensitive to state interests and productive of discord.

C

Our decisions instruct over and over again that, in the adjudication of diversity cases, state interests—whether advanced in a statute, e.g., Cohen, or a procedural rule, e.g., Gasperini—warrant our respectful consideration. Yet today, the Court gives no quarter to New York's limitation on statutory damages and requires the lower courts to thwart the regulatory policy at stake: To prevent excessive damages, New York's law controls the penalty to which a defendant may be exposed in a single suit. The story behind § 901(b)'s enactment deserves telling.

In 1975, the Judicial Conference of the State of New York proposed a new class-action statute designed "to set up a flexible, functional scheme" that would provide "an effective, but controlled group remedy." Judicial Conference Report on CPLR, reprinted in 1975 N.Y. Laws pp. 1477, 1493 (McKinney). As originally drafted, the legislation addressed only the procedural aspects of class actions; it specified, for example, five prerequisites for certification, eventually codified at § 901(a), that closely tracked those listed in Rule 23. See CPLR § 901(a) (requiring, for class certification, numerosity, predominance, typicality, adequacy of representation, and superiority).

While the Judicial Conference proposal was in the New York Legislature's hopper, "various groups advocated for the addition of a provision that would prohibit class action plaintiffs from being awarded a statutorily-created penalty ... except when expressly authorized in the pertinent statute." Sperry v. Crompton Corp., 8 N.Y.3d 204, 211, 831 N.Y.S.2d 760, 863 N.E.2d 1012, 1015 (2007). These constituents "feared that recoveries beyond actual damages could lead to excessively harsh results." Ibid. "They also argued that there was no need to permit class actions ... [because] statutory penalties ... provided an aggrieved party with a sufficient economic incentive to pursue a claim." Ibid. Such penalties, constituents observed, often far exceed a plaintiff's actual damages. "When lumped together," they argued, "penalties and class actions produce overkill." Attachment to Letter from G. Perkinson, New York State Council of Retail Merchants, Inc., to J. Gribetz, Executive Chamber (June 4, 1975) (Legislative Report), Bill Jacket, L. 1975, Ch. 207.

Aiming to avoid "annihilating punishment of the defendant," the New York Legislature amended the proposed statute to bar the recovery of statutory damages in class actions. V. Alexander, Practice Commentaries, C901:11, reprinted in 7B McKinney's Consolidated Laws of New York Ann., p. 104 (2006) (internal quotation marks omitted). In his signing statement, Governor Hugh Carey stated that the new statute "empowers the court to prevent abuse of the class action device and provides a controlled remedy." Memorandum on Approving L. 1975, Ch. 207, reprinted in 1975 N.Y. Laws, at 1748 (emphasis added).

"[T]he final bill ... was the result of a compromise among competing interests." Sperry, 8 N.Y.3d at 211, 831 N.Y.S.2d 760, 863 N.E.2d at 1015. Section 901(a) allows [1465] courts leeway in deciding whether to certify a class, but § 901(b) rejects the use of the class mechanism to pursue the particular remedy of statutory damages. The limitation was not designed with the fair conduct or efficiency of litigation in mind. Indeed, suits seeking statutory damages are arguably best suited to the class device because individual proof of actual damages is unnecessary. New York's decision instead to block class-action proceedings for statutory damages therefore makes scant sense, except as a means to a manifestly substantive end: Limiting a defendant's liability in a single lawsuit in order to prevent the exorbitant inflation of penalties—remedies the New York Legislature created with individual suits in mind.^[36]

D

Shady Grove contends—and the Court today agrees—that Rule 23 unavoidably preempts New York's prohibition on the recovery of statutory damages in class actions. The Federal Rule, the Court emphasizes, states that Shady Grove's suit "may be" maintained as a class action, which conflicts with § 901(b)'s instruction that it "may not" so proceed. Ante at 1437 (internal quotation marks omitted and emphasis deleted). Accordingly, the Court insists, § 901(b) "cannot apply in diversity suits unless Rule 23 is ultra vires." Ibid. Concluding that Rule 23 does not violate the Rules Enabling Act, the Court holds that the federal provision controls Shady Grove's ability to seek, on behalf of a class, a statutory penalty of over $5,000,000. Ante at 1442-1444 (plurality opinion); ante at 1457-1460 (STEVENS, J., concurring in part and concurring in judgment).

The Court, I am convinced, finds conflict where none is necessary. Mindful of the history behind § 901(b)'s enactment, the thrust of our precedent, and the substantive-rights limitation in the Rules Enabling Act, I conclude, as did the Second Circuit and every District Court to have considered the question in any detail,^[37] that Rule 23 does not collide with § 901(b). As the Second Circuit well understood, Rule 23 prescribes the considerations relevant to class certification and postcertification proceedings—but it does not command that a particular remedy be available when a party sues in a representative capacity. See 549 F.3d 137, 143 (2008).^[38] Section 901(b), [1466] in contrast, trains on that latter issue. Sensibly read, Rule 23 governs procedural aspects of class litigation, but allows state law to control the size of a monetary award a class plaintiff may pursue.

In other words, Rule 23 describes a method of enforcing a claim for relief, while § 901(b) defines the dimensions of the claim itself. In this regard, it is immaterial that § 901(b) bars statutory penalties in wholesale, rather than retail, fashion. The New York Legislature could have embedded the limitation in every provision creating a cause of action for which a penalty is authorized; § 901(b) operates as shorthand to the same effect. It is as much a part of the delineation of the claim for relief as it would be were it included claim by claim in the New York Code.

The Court single-mindedly focuses on whether a suit "may" or "may not" be maintained as a class action. See ante at 1437-1439. Putting the question that way, the Court does not home in on the reason why. Rule 23 authorizes class treatment for suits satisfying its prerequisites because the class mechanism generally affords a fair and efficient way to aggregate claims for adjudication. Section 901(b) responds to an entirely different concern; it does not allow class members to recover statutory damages because the New York Legislature considered the result of adjudicating such claims en masse to be exorbitant.^[39] The fair and efficient conduct of class litigation is the legitimate concern of Rule 23; the remedy for an infraction of state law, however, is the legitimate concern of the State's lawmakers and not of the federal rulemakers. Cf. Ely, The Irrepressible Myth of Erie, 87 Harv. L.Rev. 693, 722 (1974) (It is relevant "whether the state provision embodies a substantive policy or represents only a procedural disagreement with the federal rulemakers respecting the fairest and most efficient way of conducting litigation.").

Suppose, for example, that a State, wishing to cap damages in class actions at $1,000,000, enacted a statute providing that "a suit to recover more than $1,000,000 may not be maintained as a class action." Under the Court's reasoning—which attributes dispositive significance to the words "may not be maintained"—Rule 23 would preempt this provision, nevermind that Congress, by authorizing the promulgation of rules of procedure for federal courts, surely did not intend to displace state-created ceilings on damages.^[40] The Court suggests [1467] that the analysis might differ if the statute "limit[ed] the remedies available in an existing class action," ante at 1439, such that Rule 23 might not conflict with a state statute prescribing that "no more than $1,000,000 may be recovered in a class action." There is no real difference in the purpose and intended effect of these two hypothetical statutes. The notion that one directly impinges on Rule 23's domain, while the other does not, fundamentally misperceives the office of Rule 23.^[41]

The absence of an inevitable collision between Rule 23 and § 901(b) becomes evident once it is comprehended that a federal court sitting in diversity can accord due respect to both state and federal prescriptions. Plaintiffs seeking to vindicate claims for which the State has provided a statutory penalty may pursue relief through a class action if they forgo statutory damages and instead seek actual damages or injunctive or declaratory relief; any putative class member who objects can opt out and pursue actual damages, if available, and the statutory penalty in an individual action. See, e.g., Mendez v. The Radec Corp., 260 F.R.D. 38, 55 (W.D.N.Y. 2009); Brzychnalski v. Unesco, Inc., 35 F.Supp.2d 351, 353 (S.D.N.Y.1999).^[42] See also Alexander, Practice Commentaries, at 105 ("Even if a statutory penalty or minimum recovery is involved, most courts hold that it can be waived, thus confining the class recovery to actual damages and eliminating the bar of CPLR 901(b)."). In this manner, the Second Circuit explained, "Rule 23's procedural requirements for class actions can be applied along with the substantive requirement of CPLR 901(b)." 549 F.3d, at 144. In sum, while phrased as responsive to the question whether certain class actions may begin, § 901(b) is unmistakably aimed at controlling how those [1468] actions must end. On that remedial issue, Rule 23 is silent.

Any doubt whether Rule 23 leaves § 901(b) in control of the remedial issue at the core of this case should be dispelled by our Erie jurisprudence, including Hanna, which counsels us to read Federal Rules moderately and cautions against stretching a rule to cover every situation it could conceivably reach.^[43] The Court states that "[t]here is no reason ... to read Rule 23 as addressing only whether claims made eligible for class treatment by some other law should be certified as class actions." Ante at 1438. To the contrary, Palmer, Ragan, Cohen, Walker, Gasperini, and Semtek provide good reason to look to the law that creates the right to recover. See supra at 1437-1439. That is plainly so on a more accurate statement of what is at stake: Is there any reason to read Rule 23 as authorizing a claim for relief when the State that created the remedy disallows its pursuit on behalf of a class? None at all is the answer our federal system should give.

Notably, New York is not alone in its effort to contain penalties and minimum recoveries by disallowing class relief; Congress, too, has precluded class treatment for certain claims seeking a statutorily designated minimum recovery. See, e.g., 15 U.S.C. § 1640(a)(2)(B) (Truth in Lending Act) ("[I]n the case of a class action... no minimum recovery shall be applicable."); § 1693m(a)(2)(B) (Electronic Fund Transfer Act) (same); 12 U.S.C. § 4010(a)(2)(B)(i) (Expedited Fund Availability Act) (same). Today's judgment denies to the States the full power Congress has to keep certain monetary awards within reasonable bounds. Cf. Beard v. Kindler, 558 U.S. ___, ___, 130 S.Ct. 612, 618-19, ___ L.Ed.2d ___ (2009) ("In light of ... federalism and comity concerns ... it would seem particularly strange to disregard state ... rules that are substantially similar to those to which we give full force in our own courts."). States may hesitate to create determinate statutory penalties in the future if they are impotent to prevent federal-court distortion of the remedy they have shaped.^[44]

By finding a conflict without considering whether Rule 23 rationally should be read to avoid any collision, the Court unwisely and unnecessarily retreats from the federalism principles undergirding Erie. Had the Court reflected on the respect for state regulatory interests endorsed in our decisions, it would have found no cause to interpret Rule 23 so woodenly—and every [1469] reason not to do so. Cf. Traynor, 37 Tex. L.Rev., at 669 ("It is bad enough for courts to prattle unintelligibly about choice of law, but unforgiveable when inquiry might have revealed that there was no real conflict.").

II

Because I perceive no unavoidable conflict between Rule 23 and § 901(b), I would decide this case by inquiring "whether application of the [state] rule would have so important an effect upon the fortunes of one or both of the litigants that failure to [apply] it would be likely to cause a plaintiff to choose the federal court." Hanna, 380 U.S. at 468, n. 9, 85 S.Ct. 1136. See Gasperini, 518 U.S. at 428, 116 S.Ct. 2211.

Seeking to pretermit that inquiry, Shady Grove urges that the class-action bar in § 901(b) must be regarded as "procedural" because it is contained in the CPLR, which "govern[s] the procedure in civil judicial proceedings in all courts of the state." Brief for Petitioner 34 (quoting CPLR § 101; emphasis in original). Placement in the CPLR is hardly dispositive. The provision held "substantive" for Erie purposes in Gasperini is also contained in the CPLR (§ 5501(c)), as are limitations periods, § 201 et seq., prescriptions plainly "substantive" for Erie purposes however they may be characterized for other purposes, see York, 326 U.S. at 109-112, 65 S.Ct. 1464. See also, e.g., 1 Restatement (Second) of Conflict of Laws § 133, Reporter's Note, p. 369 (1969) (hereinafter Restatement) ("Under the rule of Erie ... the federal courts have classified the burden of persuasion as to contributory negligence as a matter of substantive law that is governed by the rule of the State in which they sit even though the courts of that State have characterized their rule as procedural for choice-of-law purposes."); Cook, "Substance" and "Procedure" in the Conflict of Laws, 42 Yale L.J. 333 (1933).

Shady Grove also ranks § 901(b) as "procedural" because "nothing in [the statute] suggests that it is limited to rights of action based on New York state law, as opposed to federal law or the law of other states"; instead it "applies to actions seeking penalties under any statute." Brief for Petitioner 35-36. See also ante at 1457-1458 (STEVENS, J., concurring in part and concurring in judgment) (Section 901(b) cannot "be understood as a rule that... serves the function of defining New York's rights or remedies" because its "text ... expressly and unambiguously applies not only to claims based on New York law but also to claims based on federal law or the law of any other State.").

It is true that § 901(b) is not specifically limited to claims arising under New York law. But neither is it expressly extended to claims arising under foreign law. The rule prescribes, without elaboration either way, that "an action to recover a penalty... may not be maintained as a class action." We have often recognized that "general words" appearing in a statute may, in fact, have limited application; "[t]he words `any person or persons,'" for example, "are broad enough to comprehend every human being. But general words must not only be limited to cases within the jurisdiction of the state, but also to those objects to which the legislature intended to apply them." United States v. Palmer, 3 Wheat. 610, 631, 4 L.Ed. 471 (1818) (opinion for the Court by Marshall, C. J.). See also Small v. United States, 544 U.S. 385, 388, 125 S.Ct. 1752, 161 L.Ed.2d 651 (2005) ("In law, a legislature that uses the statutory phrase `any person' may or may not mean to include `persons' outside the jurisdiction of the state." (some internal quotation marks omitted)); Flora v. United States, 362 U.S. 145, 149, 80 [1470] S.Ct. 630, 4 L.Ed.2d 623 (1960) (The term "`any sum' is a catchall [phrase,] ... but to say this is not to define what it catches.").

Moreover, Shady Grove overlooks the most likely explanation for the absence of limiting language: New York legislators make law with New York plaintiffs and defendants in mind, i.e., as if New York were the universe. See Baxter, Choice of Law and the Federal System, 16 Stan. L.Rev. 1, 11 (1963) ("[L]awmakers often speak in universal terms but must be understood to speak with reference to their constituents."); cf. Smith v. United States, 507 U.S. 197, 204, n. 5, 113 S.Ct. 1178, 122 L.Ed.2d 548 (1993) (presumption against extraterritoriality rooted in part in "the commonsense notion that Congress generally legislates with domestic concerns in mind").

The point was well put by Brainerd Currie in his seminal article on governmental interest analysis in conflict-of-laws cases. The article centers on a now-archaic Massachusetts law that prevented married women from binding themselves by contract as sureties for their husbands. Discussing whether the Massachusetts prescription applied to transactions involving foreign factors (a foreign forum, foreign place of contracting, or foreign parties), Currie observed:

"When the Massachusetts legislature addresses itself to the problem of married women as sureties, the undeveloped image in its mind is that of Massachusetts married women, husbands, creditors, transactions, courts, and judgments. In the history of Anglo-American law the domestic case has been normal, the conflict-of-laws case marginal." Married Women's Contracts: A Study in Conflict-of-Laws Method, 25 U. Chi. L.Rev. 227, 231 (1958) (emphasis added).

Shady Grove's suggestion that States must specifically limit their laws to domestic rights of action if they wish their enactments to apply in federal diversity litigation misses the obvious point: State legislators generally do not focus on an interstate setting when drafting statutes.^[45]

Shady Grove also observes that a New York court has applied § 901(b) to a federal claim for relief under the Telephone Consumer Protection Act of 1991 (TCPA), 47 U.S.C. § 227, see Rudgayzer & Gratt v. Cape Canaveral Tour & Travel, Inc., 22 App. Div.3d 148, 799 N.Y.S.2d 795 (2005), thus revealing § 901(b)'s "procedural" cast. Brief for Petitioner 36. We note first that the TCPA itself calls for the application of state law. See Rudgayzer, 22 App. Div.3d, at 149-150, 799 N.Y.S.2d, at 796-797 (federal action authorized in state court "if otherwise permitted by the laws or rules of the court of [the] State" (quoting 47 U.S.C. § 227(b)(3))). See also Gottlieb v. Carnival Corp., 436 F.3d 335, 342 (2d Cir.2006) (SOTOMAYOR, J.) [1471] ("Congress sought, via the TCPA, to enact the functional equivalent of a state law."). The TCPA, the Supreme Court of Connecticut has recognized, thus "carves out an exception to th[e] general rule" that "when Erie ... is reversed ..., a state court hearing a federal case is normally required to apply federal substantive law": "Under § 227(b)(3) ... it is state substantive law that determines, as a preliminary matter, whether a federal action under the act may be brought in state court." Weber v. U.S. Sterling Securities, Inc., 282 Conn. 722, 736, 924 A.2d 816, 826 (2007) (in TCPA action governed by New York substantive law, § 901(b) applied even though the claim was pursued in Connecticut state court).

Moreover, statutes qualify as "substantive" for Erie purposes even when they have "procedural" thrusts as well. See, e.g., Cohen, 337 U.S, at 555, 69 S.Ct. 1221; cf. Woods v. Interstate Realty Co., 337 U.S. 535, 536-538, and n. 1, 69 S.Ct. 1235, 93 L.Ed. 1524 (1949) (holding diversity case must be dismissed based on state statute that, by its terms, governed only proceedings in state court). Statutes of limitations are, again, exemplary. They supply "substantive" law in diversity suits, see York, 326 U.S. at 109-112, 65 S.Ct. 1464, even though, as Shady Grove acknowledges, state courts often apply the forum's limitations period as a "procedural" bar to claims arising under the law of another State, see Reply Brief 24, n. 16; Tr. of Oral Arg. 16-17. See also Restatement §§ 142-143 (when adjudicating a foreign cause of action, State may use either its own or the foreign jurisdiction's statute of limitations, whichever is shorter). Similarly, federal courts sitting in diversity give effect to state laws governing the burden of proving contributory negligence, see Palmer v. Hoffman, 318 U.S. 109, 117, 63 S.Ct. 477, 87 L.Ed. 645 (1943), yet state courts adjudicating foreign causes of action often apply their own local law to this issue. See Restatement § 133 and Reporter's Note.

In short, Shady Grove's effort to characterize § 901(b) as simply "procedural" cannot successfully elide this fundamental norm: When no federal law or rule is dispositive of an issue, and a state statute is outcome affective in the sense our cases on Erie (pre and post-Hanna) develop, the Rules of Decision Act commands application of the State's law in diversity suits. Gasperini, 518 U.S. at 428, 116 S.Ct. 2211; Hanna, 380 U.S. at 468, n. 9, 85 S.Ct. 1136; York, 326 U.S. at 109, 65 S.Ct. 1464. As this case starkly demonstrates, if federal courts exercising diversity jurisdiction are compelled by Rule 23 to award statutory penalties in class actions while New York courts are bound by § 901(b)'s proscription, "substantial variations between state and federal [money judgments] may be expected." Gasperini, 518 U.S. at 430, 116 S.Ct. 2211 (quoting Hanna, 380 U.S. at 467-468, 85 S.Ct. 1136 (internal quotation marks omitted)). The "variation" here is indeed "substantial." Shady Grove seeks class relief that is ten thousand times greater than the individual remedy available to it in state court. As the plurality acknowledges, ante at 1448, forum shopping will undoubtedly result if a plaintiff need only file in federal instead of state court to seek a massive monetary award explicitly barred by state law. See Gasperini, 518 U.S. at 431, 116 S.Ct. 2211 ("Erie precludes a recovery in federal court significantly larger than the recovery that would have been tolerated in state court.").^[46] The "accident of diversity of [1472] citizenship," Klaxon Co. v. Stentor Elec. Mfg. Co., 313 U.S. 487, 496, 61 S.Ct. 1020, 85 L.Ed. 1477 (1941), should not subject a defendant to such augmented liability. See Hanna, 380 U.S. at 467, 85 S.Ct. 1136 ("The Erie rule is rooted in part in a realization that it would be unfair for the character or result of a litigation materially to differ because the suit had been brought in a federal court.").

It is beyond debate that "a statutory cap on damages would supply substantive law for Erie purposes." Gasperini, 518 U.S. at 428, 116 S.Ct. 2211. See also id. at 439-440, 116 S.Ct. 2211 (STEVENS, J., dissenting) ("A state-law ceiling on allowable damages ... is a substantive rule of decision that federal courts must apply in diversity cases governed by New York law."); id. at 464, 116 S.Ct. 2211 (SCALIA, J., dissenting) ("State substantive law controls what injuries are compensable and in what amount."). In Gasperini, we determined that New York's standard for measuring the alleged excessiveness of a jury verdict was designed to provide a control analogous to a damages cap. Id. at 429, 116 S.Ct. 2211. The statute was framed as "a procedural instruction," we noted, "but the State's objective [wa]s manifestly substantive." Ibid.

Gasperini's observations apply with full force in this case. By barring the recovery of statutory damages in a class action, § 901(b) controls a defendant's maximum liability in a suit seeking such a remedy. The remedial provision could have been written as an explicit cap: "In any class action seeking statutory damages, relief is limited to the amount the named plaintiff would have recovered in an individual suit." That New York's Legislature used other words to express the very same meaning should be inconsequential.

We have long recognized the impropriety of displacing, in a diversity action, state-law limitations on state-created remedies. See Woods, 337 U.S. at 538, 69 S.Ct. 1235 (in a diversity case, a plaintiff "barred from recovery in the state court ... should likewise be barred in the federal court"); York, 326 U.S. at 108-109, 65 S.Ct. 1464 (federal court sitting in diversity "cannot afford recovery if the right to recover is made unavailable by the State nor can it substantively affect the enforcement of the right as given by the State"). Just as Erie precludes a federal court from entering a deficiency judgment when a State has "authoritatively announced that [such] judgments cannot be secured within its borders," Angel v. Bullington, 330 U.S. 183, 191, 67 S.Ct. 657, 91 L.Ed. 832 (1947), so too Erie should prevent a federal court from awarding statutory penalties aggregated through a class action when New York prohibits this recovery. See also Ragan, 337 U.S. at 533, 69 S.Ct. 1233 ("Where local law qualifies or abridges [a claim], the federal court must follow suit. Otherwise there is a different measure of the cause of action in one court than in the other, and the principle of Erie ... is transgressed."). In sum, because "New York substantive law governs [this] claim for relief, New York law ... guide[s] the allowable damages." Gasperini, 518 U.S. at 437, 116 S.Ct. 2211.^[47]

[1473] III

The Court's erosion of Erie's federalism grounding impels me to point out the large irony in today's judgment. Shady Grove is able to pursue its claim in federal court only by virtue of the recent enactment of the Class Action Fairness Act of 2005 (CAFA), 28 U.S.C. § 1332(d). In CAFA, Congress opened federal-court doors to state-law-based class actions so long as there is minimal diversity, at least 100 class members, and at least $5,000,000 in controversy. Ibid. By providing a federal forum, Congress sought to check what it considered to be the overreadiness of some state courts to certify class actions. See, e.g., S.Rep. No. 109-14, p. 4 (2005) (CAFA prevents lawyers from "gam[ing] the procedural rules [to] keep nationwide or multi-state class actions in state courts whose judges have reputations for readily certifying classes." (internal quotation marks omitted)); id. at 22 (disapproving "the `I never met a class action I didn't like' approach to class certification" that "is prevalent in state courts in some localities"). In other words, Congress envisioned fewer— not more—class actions overall. Congress surely never anticipated that CAFA would make federal courts a mecca for suits of the kind Shady Grove has launched: class actions seeking state-created penalties for claims arising under state law—claims that would be barred from class treatment in the State's own courts. Cf. Woods, 337 U.S. at 537, 69 S.Ct. 1235 ("[T]he policy of Erie ... preclude[s] maintenance in ... federal court... of suits to which the State ha[s] closed its courts.").^[48]

* * *

I would continue to approach Erie questions in a manner mindful of the purposes underlying the Rules of Decision Act and the Rules Enabling Act, faithful to precedent, and respectful of important state interests. I would therefore hold that the New York Legislature's limitation on the recovery of statutory damages applies in this case, and would affirm the Second Circuit's judgment.

[1]N.Y. Civ. Prac. Law Ann. § 901 (West 2006) provides:

"(a) One or more members of a class may sue or be sued as representative parties on behalf of all if:"

"1. the class is so numerous that joinder of all members, whether otherwise required or permitted, is impracticable;"

"2. there are questions of law or fact common to the class which predominate over any questions affecting only individual members;"

"3. the claims or defenses of the representative parties are typical of the claims or defenses of the class;"

"4. the representative parties will fairly and adequately protect the interests of the class; and"

"5. a class action is superior to other available methods for the fair and efficient adjudication of the controversy."

"(b) Unless a statute creating or imposing a penalty, or a minimum measure of recovery specifically authorizes the recovery thereof in a class action, an action to recover a penalty, or minimum measure of recovery created or imposed by statute may not be maintained as a class action."

[2]Rule 23(a) provides:

"(a) Prerequisites. One or more members of a class may sue or be sued as representative parties on behalf of all members only if:"

"(1) the class is so numerous that joinder of all members is impracticable;"

"(2) there are questions of law or fact common to the class;"

"(3) the claims or defenses of the representative parties are typical of the claims or defenses of the class; and".

"(4) the representative parties will fairly and adequately protect the interests of the class."

Subsection (b) says that "[a] class action may be maintained if Rule 23(a) is satisfied and if" the suit falls into one of three described categories (irrelevant for present purposes).

[3] Shady Grove had asserted jurisdiction under 28 U.S.C. § 1332(d)(2), which relaxes, for class actions seeking at least $5 million, the rule against aggregating separate claims for calculation of the amount in controversy. See Exxon Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546, 571, 125 S.Ct. 2611, 162 L.Ed.2d 502 (2005).

[4] Contrary to the dissent's implication, post at 1466-1467 we express no view as to whether state laws that set a ceiling on damages recoverable in a single suit, see App. A to Brief for Respondent, are pre-empted. Whether or not those laws conflict with Rule 23, § 901(b) does conflict because it addresses not the remedy, but the procedural right to maintain a class action. As Allstate and the dissent note, several federal statutes also limit the recovery available in class actions. See, e.g., 12 U.S.C. § 2605(f)(2)(B); 15 U.S.C. § 1640(a)(2)(B); 29 U.S.C. § 1854(c)(1). But Congress has plenary power to override the Federal Rules, so its enactments, unlike those of the States, prevail even in case of a conflict.

[5] But see, e.g., Asher v. Abbott Labs., 290 App. Div.2d 208, 737 N.Y.S.2d 4 (2002) (treble damages under N.Y. Gen. Bus. Law § 340(5) are nonwaivable, wherefore class actions under that law are barred).

[6] Our decision in Walker v. Armco Steel Corp., 446 U.S. 740, 100 S.Ct. 1978, 64 L.Ed.2d 659 (1980), discussed by the dissent, post at 1462-1463, 1466-1467, n. 8, is not to the contrary. There we held that Rule 3 (which provides that a federal civil action is "`commenced'" by filing a complaint in federal court) did not displace a state law providing that "`[a]n action shall be deemed commenced, within the meaning of this article [the statute of limitations], as to each defendant, at the date of the summons which is served on him . . . .'" 446 U.S. at 743, n. 4, 100 S.Ct. 1978 (quoting Okla. Stat., Tit. 12, § 97 (1971); alteration in original, emphasis added). Rule 3, we explained, "governs the date from which various timing requirements of the Federal Rules begin to run, but does not affect state statutes of limitations" or tolling rules, which it did not "purpor[t] to displace." 446 U.S. at 751, 750, 100 S.Ct. 1978. The texts were therefore not in conflict. While our opinion observed that the State's actual-service rule was (in the State's judgment) an "integral part of the several policies served by the statute of limitations," id. at 751, 100 S.Ct. 1978, nothing in our decision suggested that a federal court may resolve an obvious conflict between the texts of state and federal rules by resorting to the state law's ostensible objectives.

[7] The dissent also suggests that we should read the Federal Rules "`with sensitivity to important state interests'" and "`to avoid conflict with important state regulatory policies.'" Post at 1463 (quoting Gasperini v. Center for Humanities, Inc., 518 U.S. 415, 427, n. 7, 438, n. 22, 116 S.Ct. 2211, 135 L.Ed.2d 659 (1996)). The search for state interests and policies that are "important" is just as standardless as the "important or substantial" criterion we rejected in Sibbach v. Wilson & Co.,312 U.S. 1, 13-14, 61 S.Ct. 422, 85 L.Ed. 479 (1941), to define the state-created rights a Federal Rule may not abridge.

If all the dissent means is that we should read an ambiguous Federal Rule to avoid "substantial variations [in outcomes] between state and federal litigation," Semtek Int'l Inc. v. Lockheed Martin Corp., 531 U.S. 497, 504, 121 S.Ct. 1021, 149 L.Ed.2d 32 (2001) (internal quotation marks omitted), we entirely agree. We should do so not to avoid doubt as to the Rule's validity—since a Federal Rule that fails Erie's forum-shopping test is not ipso facto invalid, see Hanna v. Plumer, 380 U.S. 460, 469-472, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965)—but because it is reasonable to assume that "Congress is just as concerned as we have been to avoid significant differences between state and federal courts in adjudicating claims," Stewart Organization, Inc. v. Ricoh Corp., 487 U.S. 22, 37-38, 108 S.Ct. 2239, 101 L.Ed.2d 22 (1988) (SCALIA, J., dissenting). The assumption is irrelevant here, however, because there is only one reasonable reading of Rule 23.

[8] The cases chronicled by the dissent, see post at 1461-1464, each involved a Federal Rule that we concluded could fairly be read not to "control the issue" addressed by the pertinent state law, thus avoiding a "direct collision" between federal and state law, Walker, 446 U.S. at 749, 100 S.Ct. 1978 (internal quotation marks omitted). But here, as in Hanna, supra at 470, 85 S.Ct. 1136, a collision is "unavoidable."

[9] The concurrence claims that in Sibbach "[t]he Court . . . had no occasion to consider whether the particular application of the Federal Rules in question would offend the Enabling Act." Post at 1454. Had Sibbach been applying the concurrence's theory, that is quite true—which demonstrates how inconsistent that theory is with Sibbach. For conformity with the Rules Enabling Act was the very issue Sibbach decided: The petitioner's position was that Rules 35 and 37 exceeded the Enabling Act's authorization, 312 U.S. at 9, 13, 61 S.Ct. 422; the Court faced and rejected that argument, id. at 13-16, 61 S.Ct. 422, and proceeded to reverse the lower court for failing to apply Rule 37 correctly, id.at 16, 61 S.Ct. 422. There could not be a clearer rejection of the theory that the concurrence now advocates.

The concurrence responds that the "the specific question of `the obligation of federal courts to apply the substantive law of a state'" was not before the Court, post at 1454 (quoting Sibbach, supra at 9, 61 S.Ct. 422). It is clear from the context, however, that this passage referred to the Erie prohibition of court-created rules that displace state law. The opinion unquestionably dealt with the Federal Rules' compliance with § 2072(b), and it adopted the standard we apply here to resolve the question, which does not depend on whether individual applications of the Rule abridge or modify state-law rights. See 312 U.S. at 13-14, 61 S.Ct. 422. To the extent Sibbach did not address the Federal Rules' validity vis- & Agrave; -vis contrary state law, Hanna surely did, see 380 U.S. at 472, 85 S.Ct. 1136, and it made clear that Sibbach's test still controls, see 380 U.S. at 464-465, 470-471, 85 S.Ct. 1136.

[10] The concurrence insists that we have misread Sibbach, since surely a Federal Rule that "in most cases" regulates procedure does not do so when it displaces one of those "rare" state substantive laws that are disguised as rules of procedure. Post at 1455 n. 13. This mistakes what the Federal Rule regulates for its incidental effects. As we have explained, supra, at 1442-1443, most Rules have some effect on litigants' substantive rights or their ability to obtain a remedy, but that does not mean the Rule itself regulates those rights or remedies.

[11] The concurrence's approach, however, is itself unfaithful to the statute's terms. Section 2072(b) bans abridgement or modification only of "substantive rights," but the concurrence would prohibit pre-emption of "procedural rules that are intimately bound up in the scope of a substantive right or remedy," post at 1458. This would allow States to force a wide array of parochial procedures on federal courts so long as they are "sufficiently intertwined with a state right or remedy." Post at 1455.

[12] The concurrence implies that Sibbach has slipped into desuetude, apparently for lack of sufficient citations. See post at 1455-1456, n. 14. We are unaware of any rule to the effect that a holding of ours expires if the case setting it forth is not periodically revalidated. In any event, the concurrence's account of our shunning of Sibbach is greatly exaggerated. Hanna did not merely cite the case, but recognized it as establishing the governing rule. 380 U.S. at 464-465, 470-471, 85 S.Ct. 1136. Mississippi Publishing Corp. v. Murphree, 326 U.S. 438, 445-446, 66 S.Ct. 242, 90 L.Ed. 185 (1946), likewise cited Sibbach and applied the same test, examining the Federal Rule, not the state law it displaced. True, Burlington Northern R. Co. v. Woods, 480 U.S. 1, 107 S.Ct. 967, 94 L.Ed.2d 1 (1987), and for that matter Business Guides, Inc. v. Chromatic Communications Enterprises, Inc., 498 U.S. 533, 111 S.Ct. 922, 112 L.Ed.2d 1140 (1991), did not cite Sibbach. But both cited and followed Hanna—which as noted held out Sibbach as setting forth the governing rule. See Burlington Northern, supra at 5-6, 8, 107 S.Ct. 967; Business Guides, supra at 552-554, 111 S.Ct. 922. Thus, while Sibbachitself may appear infrequently in the U.S. Reports, its rule—and in particular its focus on the Federal Rule as the proper unit of analysis—is alive and well.

In contrast, Hanna's obscure obiter dictum that a court "need not wholly blind itself" to a Federal Rule's effect on a case's outcome, 380 U.S. at 473, 85 S.Ct. 1136—which the concurrence invokes twice, post at 1452, 1455-1456, n. 14—has never resurfaced in our opinions in the 45 years since its first unfortunate utterance. Nor does it cast doubt on Sibbach's straightforward test: As the concurrence notes, Hanna cited Sibbach for that statement, 380 U.S. at 473, 85 S.Ct. 1136, showing it saw no inconsistency between the two.

[13] The concurrence is correct, post at 1453, n. 9, that under our disposition any rule that "really regulates procedure," Sibbach, supra at 14, 61 S.Ct. 422, will pre-empt a conflicting state rule, however "bound up" the latter is with substantive law. The concurrence is wrong, however, that that result proves our interpretation of § 2072(b) implausible, postat 1453, n. 9. The result is troubling only if one stretches the term "substantive rights" in § 2072(b) to mean not only state-law rights themselves, but also any state-law procedures closely connected to them. Neither the text nor our precedent supports that expansive interpretation. The examples the concurrence offers—statutes of limitations, burdens of proof, and standards for appellate review of damages awards—do not make its broad definition of substantive rights more persuasive. They merely illustrate that in rare cases it may be difficult to determine whether a rule "really regulates" procedure or substance. If one concludes the latter, there is no pre-emption of the state rule; the Federal Rule itself is invalid.

The concurrence's concern would make more sense if many Federal Rules that effectively alter state-law rights "bound up with procedures" would survive under Sibbach. But as the concurrence concedes, post at 1454, n. 10, very few would do so. The possible existence of a few outlier instances does not prove Sibbach's interpretation is absurd. Congress may well have accepted such anomalies as the price of a uniform system of federal procedure.

[14] The concurrence argues that its approach is no more "taxing" than ours because few if any Federal Rules that are "facially valid" under the Enabling Act will fail the concurrence's test. Post at 1453-1454, and n. 10. But that conclusion will be reached only after federal courts have considered hundreds of state rules applying the concurrence's inscrutable standard.

[15] The concurrence insists that the task will be easier if courts can "conside[r] the nature and functions of the state law," post at 1454, n. 10, regardless of the law's "form," post at 1449 (emphasis deleted), i.e., what the law actually says. We think that amorphous inquiry into the "nature and functions" of a state law will tend to increase, rather than decrease, the difficulty of classifying Federal Rules as substantive or procedural. Walking through the concurrence's application of its test to § 901(b), post at 1457-1460, gives little reason to hope that its approach will lighten the burden for lower courts.

[16] See also Gasperini v. Center for Humanities, Inc., 518 U.S. 415, 427, 116 S.Ct. 2211, 135 L.Ed.2d 659 (1996); E. Chemerinsky, Federal Jurisdiction § 5.3, p. 327 (5th ed.2007) (hereinafter Chemerinsky); 17A J. Moore et al., Moore's Federal Practice § 124.01[1] (3d ed.2009) (hereinafter Moore).

[17] The Erie choice requires that the court consider "the twin aims of the Erie rule: discouragement of forum-shopping and avoidance of inequitable administration of the laws." Hanna v. Plumer, 380 U.S. 460, 468, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965); see also Gasperini, 518 U.S. at 427-428, 116 S.Ct. 2211 (describing Erie inquiry).

[18] See Chemerinsky § 5.3, at 321 (observing that courts "have struggled to develop an approach that permits uniform procedural rules to be applied in federal court while still allowing state substantive law to govern").

[19] Cf. Milam v. State Farm Mut. Auto. Ins. Co., 972 F.2d 166, 170 (C.A.7 1992) (Posner, J.) (holding that "where a state in furtherance of its substantive policy makes it more difficult to prove a particular type of state-law claim, the rule by which it does this, even if denominated a rule of evidence or cast in evidentiary terms, will be given effect in a diversity suit as an expression of state substantive policy"); Moore § 124.09[2] (listing examples of federal courts that apply state evidentiary rules to diversity suits). Other examples include state-imposed burdens of proof.

[20] I thus agree with Justice GINSBURG, post at 1461-1463, that a federal rule, like any federal law, must be interpreted in light of many different considerations, including "sensitivity to important state interests," post at 1463, and "regulatory policies," post at 1460. See Stewart Organization, Inc. v. Ricoh Corp., 487 U.S. 22, 37-38, 108 S.Ct. 2239, 101 L.Ed.2d 22 (1988) (SCALIA, J., dissenting) ("We should assume . . . when it is fair to do so, that Congress is just as concerned as we have been to avoid significant differences between state and federal courts in adjudicating claims . . . . Thus, in deciding whether a federal. . . Rule of Procedure encompasses a particular issue, a broad reading that would create significant disuniformity between state and federal courts should be avoided if the text permits"). I disagree with Justice GINSBURG, however, about the degree to which the meaning of federal rules may be contorted, absent congressional authorization to do so, to accommodate state policy goals.

[21] See also Ortiz v. Fibreboard Corp., 527 U.S. 815, 842, 845, 119 S.Ct. 2295, 144 L.Ed.2d 715 (1999) (adopting "limiting construction" of Federal Rule of Civil Procedure 23 that, inter alia, "minimizes potential conflict with the Rules Enabling Act"); Amchem Products, Inc. v. Windsor, 521 U.S. 591, 612-613, 117 S.Ct. 2231, 138 L.Ed.2d 689 (1997) (observing that federal rules "must be interpreted in keeping with the Rules Enabling Act, which instructs that rules of procedure `shall not abridge, enlarge or modify any substantive right'").

[22] This understanding of the Enabling Act has been the subject of substantial academic criticism, and rightfully so. See, e.g., Wright § 4509, at 264, 269-270, 272; Ely, The Irrepressible Myth of Erie, 87 Harv. L.Rev. 693, 719 (1974) (hereinafter Ely); see also R. Fallon, J. Manning, D. Meltzer, & D. Shapiro, Hart and Wechsler's, The Federal Courts and the Federal System 593, n. 6 (6th ed.2009) (discussing Ely).

[23] Justice SCALIA concedes as much, see ante at 1445-1446, but argues that insofar as I allow for the possibility that a federal rule might violate the Enabling Act when it displaces a seemingly procedural state rule, my approach is itself "unfaithful to the statute's terms," which cover "substantive rights" but not "procedural rules," ante at 1446, n. 11 (internal quotation marks omitted). This is not an objection to my interpretation of the Enabling Act—that courts must look to whether a federal rule alters substantive rights in a given case—but simply to the way I would apply it, allowing for the possibility that a state rule that regulates something traditionally considered to be procedural might actually define a substantive right. JUSTICE SCALIA's objection, moreover, misses the key point: In some instances, a state rule that appears procedural really is not. A rule about how damages are reviewed on appeal may really be a damages cap. See Gasperini, 518 U.S. at 427, 116 S.Ct. 2211. A rule that a plaintiff can bring a claim for only three years may really be a limit on the existence of the right to seek redress. A rule that a claim must be proved beyond a reasonable doubt may really be a definition of the scope of the claim. These are the sorts of rules that one might describe as "procedural," but they nonetheless define substantive rights. Thus, if a federal rule displaced such a state rule, the federal rule would have altered the State's "substantive rights."

[24] The plurality's interpretation of the Enabling Act appears to mean that no matter how bound up a state provision is with the State's own rights or remedies, any contrary federal rule that happens to regulate "the manner and the means by which the litigants' rights are enforced," ante at 1442 (internal quotation marks omitted), must govern. There are many ways in which seemingly procedural rules may displace a State's formulation of its substantive law. For example, statutes of limitations, although in some sense procedural rules, can also be understood as a temporal limitation on legally created rights; if this Court were to promulgate a federal limitations period, federal courts would still, in some instances, be required to apply state limitations periods. Similarly, if the federal rules altered the burden of proof in a case, this could eviscerate a critical aspect—albeit one that deals with how a right is enforced— of a State's framework of rights and remedies. Or if a federal rule about appellate review displaced a state rule about how damages are reviewed on appeal, the federal rule might be pre-empting a state damages cap. Cf. Gasperini,518 U.S. at 427, 116 S.Ct. 2211.

Justice SCALIA responds that some of these federal rules might be invalid under his view of the Enabling Act because they may not "really regulat[e] procedure." Ante at 1447, n. 13 (internal quotation marks omitted). This response, of course, highlights how empty the plurality's test really is. See n. 10, infra. The response is also limited to those rules that can be described as "regulat[ing]" substance, ante at ___; it does not address those federal rules that alter the right at issue in the litigation, see Sibbach v. Wilson & Co., 312 U.S. 1, 13-14, 61 S.Ct. 422, 85 L.Ed. 479 (1941), only when they displace particular state laws. JUSTICE SCALIA speculates that "Congress may well have accepted" the occasional alteration of substantive rights "as the price of a uniform system of federal procedure." Ante at 1446-1447, n. 13. Were we forced to speculate about the balance that Congress struck, I might very well agree. But no speculation is necessary because Congress explicitly told us that federal rules "shall not" alter "any" substantive right. § 2072(b).

[25] It will be rare that a federal rule that is facially valid under 28 U.S.C. § 2072 will displace a State's definition of its own substantive rights. See Wright § 4509, at 272 (observing that "unusual cases occasionally might arise in which . . . because of an unorthodox state rule of law, application of a Civil Rule . . . would intrude upon state substantive rights"). JUSTICE SCALIA's interpretation, moreover, is not much more determinative than mine. Although it avoids courts' having to evaluate state law, it tasks them with figuring out whether a federal rule is really "procedural." It is hard to know the answer to that question and especially hard to resolve it without considering the nature and functions of the state law that the federal rule will displace. The plurality's "`test' is no test at all—in a sense, it is little more than the statement that a matter is procedural if, by revelation, it is procedural." Id., § 4509 at 264.

[26] The petitioner in Sibbach argued only that federal rules could not validly address subjects involving "important questions of policy," Supp. Brief of Petitioner, O.T.1940, No. 28, p. 7; see also Reply to Brief of Respondent, O.T. 1940, No. 28, p. 2 (summarizing that the petitioner argued only that "[t]he right not to be compelled to submit to a physical examination" is "a `substantive' right forbidden by Congress" to be addressed by the Federal Rules of Civil Procedure, "even though in theory the right is not of the character determinative of litigation"). In the petitioner's own words, "[t]his contention . . . [did] not in itself involve the [applicable] law of Illinois," ibid., and the petitioner in her briefing referenced the otherwise applicable state law only "to show that [she] was in a position to make the contention," ibid., that is, to show that the federal court was applying a federal rule and not, under the Rules of Decision Act, applying state law, see id. at 3.

[27] The plurality defends its view by including a long quote from two paragraphs of Sibbach. Ante at 1443-1444. But the quoted passage of Sibbach describes only a facial inquiry into whether federal rules may "deal with" particular subject matter. 312 U.S. at 13, 61 S.Ct. 422. The plurality's block quote, moreover, omits half of one of the quoted paragraphs, in which the Court explained that the term "substantive rights" in the Enabling Act "certainly embraces such rights" as "rights conferred by law to be protected and enforced," such as "the right not to be injured in one's person by another's negligence" and "to redress [such] infraction." Ibid. But whether a federal rule, for example, enlarges the right "to redress [an] infraction," will depend on the state law that it displaces.

[28] Put another way, even if a federal rule in most cases "really regulates procedure," Sibbach, 312 U.S. at 14, 61 S.Ct. 422, it does not "really regulat[e] procedure" when it displaces those rare state rules that, although "procedural" in the ordinary sense of the term, operate to define the rights and remedies available in a case. This is so because what is procedural in one context may be substantive in another. See Hanna, 380 U.S. at 471, 85 S.Ct. 1136; Guaranty Trust Co. v. York, 326 U.S. 99, 108, 65 S.Ct. 1464, 89 L.Ed. 2079 (1945).

[29] Although this Court's decision in Hanna cited Sibbach, that is of little significance. Hanna did not hold that any seemingly procedural federal rule will always govern, even when it alters a substantive state right; nor, as in Sibbach, was the argument that I now make before the Court. Indeed, in Hanna we cited Sibbach's statement that the Enabling Act prohibits federal rules that alter the rights to be adjudicated by the litigants, 312 U.S. at 13-14, 61 S.Ct. 422, for the proposition that "a court, in measuring a Federal Rule against the standards contained in the Enabling Act. . . need not wholly blind itself to the degree to which the Rule makes the character and result of the federal litigation stray from the course it would follow in state courts," 380 U.S. at 473, 85 S.Ct. 1136. And most of our subsequent decisions that have squarely addressed the framework for applying federal rules in diversity cases have not mentioned Sibbach at all but cited only Hanna. See, e.g., Burlington Northern R. Co. v. Woods,480 U.S. 1, 5, 107 S.Ct. 967, 94 L.Ed.2d 1 (1987).

Justice SCALIA notes that in Mississippi Publishing Corp. v. Murphree, 326 U.S. 438, 66 S.Ct. 242, 90 L.Ed. 185 (1946), we used language that supported his view. See ante at 1442-1443. But in that case, we contemplated only that the Federal Rule in question might have "incidental effects . . . upon the rights of litigants," explaining that "[t]he fact that the application of Rule 4(f) will operate to subject petitioner's rights to adjudication by the district court for northern Mississippi" rather than southern Mississippi "will undoubtedly affect those rights." 326 U.S. at 445-446, 66 S.Ct. 242. There was no suggestion that by affecting the method of enforcing the rights in that case, the federal rules could plausibly abridge, enlarge, or modify the rights themselves.

[30] Nor do I see how it follows from the dissent's premises that a class cannot be certified. The dissent contends that § 901(b) is a damages "limitation," post at 1463, n. 2, 1464, 1464-1465, 1466, 1473, or "proscription," post at 1466, n. 6, 1471, whereas Rule 23 "does not command that a particular remedy be available when a party sues in a representative capacity," postat 1465, and that consequently both provisions can apply. Yet even if the dissent's premises were correct, Rule 23 would still control the question whether petitioner may certify a class, and § 901(b) would be relevant only to determine whether petitioner, at the conclusion of a class-action lawsuit, may collect statutory damages.

It may be that if the dissent's interpretation of § 901(b) were correct, this class could not (or has not) alleged sufficient damages for the federal court to have jurisdiction, see 28 U.S.C. § 1332(d)(6). But that issue was not raised in respondent's motion to dismiss (from which the case comes to this Court), and it was not squarely presented to the Court. In any event, although the lead plaintiff has "acknowledged that its individual claim" is for less than the required amount in controversy, see 549 F.3d 137, 140 (C.A.2 2008), we do not know what actual damages the entire class can allege. Thus, even if the Court were to adopt all of the dissent's premises, I believe the correct disposition would be to vacate and remand for further consideration of whether the required amount in controversy has or can be met.

[31] In its Erie analysis, the dissent observes that when sovereigns create laws, the enacting legislatures sometimes assume those laws will apply only within their territory. See post at 1469-1471. That is a true fact, but it does not do very much work for the dissent's position. For one thing, as the dissent observes, this Erie analysis is relevant only if there is no conflict between Rule 23 and § 901(b), and the court can thus apply both. Post at 1469. But because, in my view, Rule 23 applies, the only question is whether it would violate the Enabling Act. See Hanna, 380 U.S. at 471, 85 S.Ct. 1136. And that inquiry is different from the Rules of Decision Act, or Erie, inquiry. See id.at 469-471, 85 S.Ct. 1136.

The dissent's citations, moreover, highlight simply that when interpreting statutes, context matters. Thus, we sometimes presume that laws cover only domestic conduct and sometimes do not, depending upon, inter alia, whether it makes sense in a given situation to assume that "the character of an act as lawful or unlawful must be determined wholly by the law of the [place] where the act is done," American Banana Co. v. United Fruit Co., 213 U.S. 347, 356, 29 S.Ct. 511, 53 L.Ed. 826 (1909). But in the context of § 901(b), a presumption against extraterritoriality makes little sense. That presumption applies almost only to laws governing what people can or cannot do. Section 901(b), however, is not directed to the conduct of persons but is instead directed to New York courts. Thus, § 901(b) is, by its own terms, not extraterritorial insofar as it states that it governs New York courts. It is possible that the New York Legislature simply did not realize that New York courts hear claims under other sources of law and that other courts hear claims under New York law, and therefore mistakenly believed that they had written a limit on New York remedies. But because New York set up § 901(b) as a general rule about how its courts operate, my strong presumption is to the contrary.

[32] To be sure, one could imagine the converse story, that a legislature would create statutory penalties but dictate that such penalties apply only when necessary to overcome the costs and inconvenience of filing a lawsuit, and thus are not necessary in a class action. But it is hard to see how that narrative applies to New York, given that New York's penalty provisions, on their face, apply to all plaintiffs, be they class or individual, and that § 901(b) addresses penalties that are created under any source of state or federal law.

[33] Justice GINSBURG asserts that class certification in this matter would "transform a $500 case into a $5,000,000 award." Post at 1460. But in fact, class certification would transform 10,000 $500 cases into one $5,000,000 case. It may be that without class certification, not all of the potential plaintiffs would bring their cases. But that is true of any procedural vehicle; without a lower filing fee, a conveniently located courthouse, easy-to-use federal procedural rules, or many other features of the federal courts, many plaintiffs would not sue.

[34] The Rules of Decision Act directs that, "[t]he laws of the several states, except where the Constitution or treaties of the United States or Acts of Congress otherwise require or provide, shall be regarded as rules of decision in civil actions in the courts of the United States, in cases where they apply." 28 U.S.C. § 1652.

[35] Justice STEVENS stakes out common ground on this point: "[F]ederal rules," he observes, "must be interpreted with some degree of `sensitivity to important state interests and regulatory policies,' ... and applied to diversity cases against the background of Congress' command that such rules not alter substantive rights and with consideration of `the degree to which the Rule makes the character and result of the federal litigation stray from the course it would follow in state courts,' Hanna [v. Plumer], 380 U.S. [460, 473, 85 S.Ct. 1136, 14 L.Ed.2d 8 (1965)]." Ante at 1449. (opinion concurring in part and concurring in judgment). See also ante at 1450 ("A `state procedural rule, though undeniably procedural in the ordinary sense of the term' may exist `to influence substantive outcomes,'... and may in some instances become so bound up with the state-created right or remedy that it defines the scope of that substantive right or remedy." (some internal quotation marks omitted)); ante at 1450 ("When a State chooses to use a traditionally procedural vehicle as a means of defining the scope of substantive rights or remedies, federal courts must recognize and respect that choice."). Nevertheless, Justice STEVENS sees no reason to read Rule 23 with restraint in this particular case; the Federal Rule preempts New York's damages limitation, in his view, because § 901(b) is "a procedural rule that is not part of New York's substantive law." Ante at 1448. This characterization of § 901(b) does not mirror reality, as I later explain. See infra at 1469-1473. But a majority of this Court, it bears emphasis, agrees that Federal Rules should be read with moderation in diversity suits to accommodate important state concerns.

[36] Even in the mine-run case, a class action can result in "potentially ruinous liability." Advisory Committee's Notes on Fed. Rule Civ. Proc. 23, 28 U.S.C.App., p. 143. A court's decision to certify a class accordingly places pressure on the defendant to settle even unmeritorious claims. See, e.g., Coopers & Lybrand v. Livesay, 437 U.S. 463, 476, 98 S.Ct. 2454, 57 L.Ed.2d 351 (1978). When representative plaintiffs seek statutory damages, pressure to settle may be heightened because a class action poses the risk of massive liability unmoored to actual injury. See, e.g., Ratner v. Chemical Bank New York Trust Co., 54 F.R.D. 412, 416 (S.D.N.Y.1972) (exercising "considerable discretion of a pragmatic nature" to refuse to certify a class because the plaintiffs suffered negligible actual damages but sought statutory damages of $13,000,000).

[37] See, e.g., In re Automotive Refinishing Paint Antitrust Litigation, 515 F.Supp.2d 544, 549-551 (E.D.Pa.2007); Leider v. Ralfe, 387 F.Supp.2d 283, 289-292 (S.D.N.Y.2005); Dornberger v. Metropolitan Life Insurance Co., 182 F.R.D. 72, 84 (S.D.N.Y.1999). See also Weber v. U.S. Sterling Securities, Inc., 282 Conn. 722, 738-739, 924 A.2d 816, 827-828 (2007) (section 901(b) applied in Connecticut state court to action governed by New York substantive law).

[38] Shady Grove projects that a dispensation in favor of Allstate would require "courts in all diversity class actions ... [to] look to state rules and decisional law rather than to Rule 23 ... in making their class certification decisions." Brief for Petitioner 55. This slippery-slope projection is both familiar and false. Cf. R. Bork, The Tempting of America 169 (1990) ("Judges and lawyers live on the slippery slope of analogies; they are not supposed to ski it to the bottom."). In this case, CPLR § 901(a) lists the state-law prerequisites for class certification, but Allstate does not contend that § 901(a) overrides Rule 23. Brief for Respondent 18 ("There is no dispute that the criteria for class certification under state law do not apply in federal court; that is the ground squarely occupied by Rule 23."). Federal courts sitting in diversity have routinely applied Rule 23's certification standards, rather than comparable state provisions. See, e.g., In re New Motor Vehicles Canadian Export Antitrust Litigation, 522 F.3d 6, 18-24 (C.A.1 2008); Order and Reasons in In re Katrina Canal Breaches Consolidated Litigation, Civ. Action No. 05-4182, 2009 WL 2447846 (E.D.La. Aug. 6, 2009).

[39] The Court disputes the strength of the evidence of legislative intent, see ante at 1440, but offers no alternative account of § 901(b)'s purpose. Perhaps this silence indicates how very hard it would be to ascribe to § 901(b) any purpose bound up with the fairness and efficiency of processing cases. On its face, the proscription is concerned with remedies, i.e., the availability of statutory damages in a lawsuit. Legislative history confirms this objective, but is not essential to revealing it.

[40] There is, of course, a difference between "justly administering [a] remedy," Sibbach v. Wilson & Co., 312 U.S. 1, 14, 61 S.Ct. 422, 85 L.Ed. 479 (1941), and prescribing the content of that remedy; if Rule 23 can be read to increase a plaintiff's recovery from $1,000,000 to some greater amount, the Rule has arguably "enlarge[d] ... [a] substantive right" in violation of the Rules Enabling Act. 28 U.S.C. § 2072(b). The plurality appears to acknowledge this point, stating that the Federal Rules we have found to be in compliance with the Act have not "altered ... available remedies." Ante at 1443. But the Court's relentless reading of Rule 23 today does exactly that: The Federal Rule, it says, authorizes the recovery of class-size statutory damages even though the New York provision instructs that such penalties shall not be available.

[41] The Court states that "[w]e cannot rewrite [a state law] to reflect our perception of legislative purpose." Ante at 1440. But we can, of course, interpret the Federal Rules in light of a State's regulatory policy to decide whether and to what extent a Rule preempts state law. See supra at 1461-1463. Just as we read Federal Rule 3 in Walker v. Armco Steel Corp., 446 U.S. 740, 751, 100 S.Ct. 1978, 64 L.Ed.2d 659 (1980), not to govern when a suit commences for purposes of tolling a state statute of limitations (although the Rule indisputably controls when an action commences for federal procedural purposes), so too we could read Rule 23 not to direct when a class action may be maintained for purposes of recovering statutory damages prescribed by state law. On this reading of Rule 23, no rewriting of § 901(b) is necessary to avoid a conflict.

[42] The New York Legislature appears to have anticipated this result. In discussing the remedial bar effected by § 901(b), the bill's sponsor explained that a "statutory class action for actual damages would still be permissible." S. Fink, [Sponsor's] Memorandum, Bill Jacket, L. 1975, Ch. 207. See also State Consumer Protection Board Memorandum (May 29, 1975), Bill Jacket, L. 1975, Ch. 207. On this understanding, New York courts routinely authorize class actions when the class waives its right to receive statutory penalties. See, e.g., Cox v. Microsoft Corp., 8 A.D.3d 39, 778 N.Y.S.2d 147 (2004); Pesantez v. Boyle Env. Servs., Inc., 251 A.D.2d 11, 673 N.Y.S.2d 659 (1998); Ridge Meadows Homeowners' Assn., Inc. v. Tara Development Co., 242 A.D.2d 947, 665 N.Y.S.2d 361 (1997); Super Glue Corp. v. Avis Rent A Car System, Inc., 132 A.D.2d 604, 517 N.Y.S.2d 764 (1987); Weinberg v. Hertz Corp., 116 A.D.2d 1, 499 N.Y.S.2d 693 (1986).

[43] The plurality notes that "we have rejected every statutory challenge to a Federal Rule that has come before us." Ante at 1442. But it omits that we have interpreted Rules with due restraint, including Rule 23, thus diminishing prospects for the success of such challenges. See Ortiz v. Fibreboard Corp., 527 U.S. 815, 842, 119 S.Ct. 2295, 144 L.Ed.2d 715 (1999); Amchem Products, Inc. v. Windsor, 521 U.S. 591, 612-613, 117 S.Ct. 2231, 138 L.Ed.2d 689 (1997); supra at 1437-1440.

[44] States have adopted a variety of formulations to limit the use of class actions to gain certain remedies or to pursue certain claims, as illustrated by the 96 examples listed in Allstate's brief. Apps. to Brief for Respondent. The Court's "one-size-fits-all" reading of Rule 23, ante at 1437, likely prevents the enforcement of all of these statutes in diversity actions—including the numerous state statutory provisions that, like § 901(b), attempt to curb the recovery of statutory damages. See, e.g., Cal. Civ.Code Ann. § 2988.5(a)(2) (West 1993); Colo.Rev.Stat. Ann. § 12-14.5-235(d) (2009); Conn. Gen.Stat. § 36a-683(a) (2009); Haw.Rev.Stat. § 489-7.5(b)(1) (2008); Ind. Code § 24-4.5-5-203(a)(2) (2004); Ky.Rev. Stat. Ann. § 367.983(1)(c) (West 2006); Mass. Gen. Laws, ch. 167B, § 20(a)(2)(B) (2008); Mich. Comp. Laws Ann. § 493.112(3)(c) (West 2005); N.M. Stat. Ann. § 58-16-15(B) (Lexis 2004); Ohio Rev.Code Ann. § 1351.08(A) (West 2004); Okla. Stat., Tit. 14A, § 5-203(1) (2007 Supp.); Wyo. Stat. Ann. § 40-19-119(a)(iii) (2009).

[45] Shady Grove's argument that § 901(b) is procedural based on its possible application to foreign claims is also out of sync with our Erie decisions, many of them involving state statutes of similarly unqualified scope. The New Jersey law at issue in Cohen v. Beneficial Industrial Loan Corp., 337 U.S. 541, 544, n. 1, 69 S.Ct. 1221, 93 L.Ed. 1528 (1949), for example, required plaintiffs to post a bond as security for costs in "any [stockholder's derivative] action." (quoting 1945 N.J. Laws ch. 131 (emphasis added)). See also, e.g., Walker, 446 U.S. at 742-743, and n. 4, 100 S.Ct. 1978 (Oklahoma statute deemed "[a]n action" commenced for purposes of the statute of limitations upon service of the summons (quoting Okla. Stat., Tit. 12, § 97 (1971))). Our characterization of a state statute as substantive for Erie purposes has never hinged on whether the law applied only to domestic causes of action. To the contrary, we have ranked as substantive a variety of state laws that the state courts apply to federal and out-of-state claims, including statutes of limitations and burden-of-proof prescriptions. See infra at 1471.

[46] In contrast, many "state rules ostensibly addressed to procedure," ante at 1441 (majority opinion)—including pleading standards and rules governing summary judgment, pre-trial discovery, and the admissibility of certain evidence—would not so hugely impact forum choices. It is difficult to imagine a scenario that would promote more forum shopping than one in which the difference between filing in state and federal court is the difference between a potential award of $500 and one of $5,000,000.

[47] There is no question that federal courts can "give effect to the substantive thrust of [§ 901(b)] without untoward alteration of the federal scheme for the trial and decision of civil cases." Gasperini, 518 U.S. at 426, 116 S.Ct. 2211. There is no risk that individual plaintiffs seeking statutory penalties will flood federal courts with state-law claims that could be managed more efficiently on a class basis; the diversity statute's amount-in-controversy requirement ensures that small state-law disputes remain in state court.

[48] It remains open to Congress, of course, to exclude from federal-court jurisdiction under the Class Action Fairness Act of 2005, 28 U.S.C. § 1332(d), claims that could not be maintained as a class action in state court.

CERTIORARI TO THE SUPREME COURT OF KANSAS

[798] Arthur R. Miller argued the cause for petitioner. With him on the briefs were Joseph W. Kennedy, Robert W. Coykendall, Kenneth Heady, William G. Paul, and T. L. Cubbage II.

Joel I. Klein argued the cause for respondents. With him on the brief were W. Luke Chapin, Ed Moore, and Harold Greenleaf.^[1]

[799] JUSTICE REHNQUIST delivered the opinion of the Court.

Petitioner is a Delaware corporation which has its principal place of business in Oklahoma. During the 1970's it produced or purchased natural gas from leased land located in 11 different States, and sold most of the gas in interstate commerce. Respondents are some 28,000 of the royalty owners possessing rights to the leases from which petitioner produced the gas; they reside in all 50 States, the District of Columbia, and several foreign countries. Respondents brought a class action against petitioner in the Kansas state court, seeking to recover interest on royalty payments which had been delayed by petitioner. They recovered judgment in the trial court, and the Supreme Court of Kansas affirmed the judgment over petitioner's contentions that the Due Process Clause of the Fourteenth Amendment prevented Kansas from adjudicating the claims of all the respondents, and that the Due Process Clause and the Full Faith and Credit Clause of Article IV of the Constitution prohibited the application of Kansas law to all of the transactions between petitioner and respondents. 235 Kan. 195, 679 P. 2d 1159 (1984). We granted certiorari to consider these claims. 469 U. S. 879 (1984). We reject petitioner's jurisdictional claim, but sustain its claim regarding the choice of law.

Because petitioner sold the gas to its customers in interstate commerce, it was required to secure approval for price increases from what was then the Federal Power Commission, and is now the Federal Energy Regulatory Commission. Under its regulations the Federal Power Commission permitted petitioner to propose and collect tentative higher gas prices, subject to final approval by the Commission. If the Commission eventually denied petitioner's proposed price increase or reduced the proposed increase, petitioner would [800] have to refund to its customers the difference between the approved price and the higher price charged, plus interest at a rate set by statute. See 18 CFR § 154.102 (1984).

Although petitioner received higher gas prices pending review by the Commission, petitioner suspended any increase in royalties paid to the royalty owners because the higher price could be subject to recoupment by petitioner's customers. Petitioner agreed to pay the higher royalty only if the royalty owners would provide petitioner with a bond or indemnity for the increase, plus interest, in case the price increase was not ultimately approved and a refund was due to the customers. Petitioner set the interest rate on the indemnity agreements at the same interest rate the Commission would have required petitioner to refund to its customers. A small percentage of the royalty owners provided this indemnity and received royalties immediately from the interim price increases; these royalty owners are unimportant to this case.

The remaining royalty owners received no royalty on the unapproved portion of the prices until the Federal Power Commission approval of those prices became final. Royalties on the unapproved portion of the gas price were suspended three times by petitioner, corresponding to its three proposed price increases in the mid-1970's. In three written opinions the Commission approved all of petitioner's tentative price increases, so petitioner paid to its royalty owners the suspended royalties of $3.7 million in 1976, $4.7 million in 1977, and $2.9 million in 1978. Petitioner paid no interest to the royalty owners although it had the use of the suspended royalty money for a number of years.

Respondents Irl Shutts, Robert Anderson, and Betty Anderson filed suit against petitioner in Kansas state court, seeking interest payments on their suspended royalties which petitioner had possessed pending the Commission's approval of the price increases. Shutts is a resident of Kansas, and the Andersons live in Oklahoma. Shutts and the Andersons [801] own gas leases in Oklahoma and Texas. Over petitioner's objection the Kansas trial court granted respondents' motion to certify the suit as a class action under Kansas law. Kan. Stat. Ann. § 60-223 et seq. (1983). The class as certified was comprised of 33,000 royalty owners who had royalties suspended by petitioner. The average claim of each royalty owner for interest on the suspended royalties was $100.

After the class was certified respondents provided each class member with notice through first-class mail. The notice described the action and informed each class member that he could appear in person or by counsel; otherwise each member would be represented by Shutts and the Andersons, the named plaintiffs. The notices also stated that class members would be included in the class and bound by the judgment unless they "opted out" of the lawsuit by executing and returning a "request for exclusion" that was included with the notice. The final class as certified contained 28,100 members; 3,400 had "opted out" of the class by returning the request for exclusion, and notice could not be delivered to another 1,500 members, who were also excluded. Less than 1,000 of the class members resided in Kansas. Only a minuscule amount, approximately one quarter of one percent, of the gas leases involved in the lawsuit were on Kansas land.

After petitioner's mandamus petition to decertify the class was denied, Phillips Petroleum v. Duckworth, No. 82-54608 (Kan., June 28, 1982), cert. denied, 459 U. S. 1103 (1983), the case was tried to the court. The court found petitioner liable under Kansas law for interest on the suspended royalties to all class members. The trial court relied heavily on an earlier, unrelated class action involving the same nominal plaintiff and the same defendant, Shutts, Executor v. Phillips Petroleum Co., 222 Kan. 527, 567 P. 2d 1292 (1977), cert. denied, 434 U. S. 1068 (1978). The Kansas Supreme Court had held in Shutts, Executor that a gas company owed interest to royalty owners for royalties suspended pending final Commission approval of a price increase. No federal statutes [802] touched on the liability for suspended royalties, and the court in Shutts, Executor held as a matter of Kansas equity law that the applicable interest rates for computation of interest on suspended royalties were the interest rates at which the gas company would have had to reimburse its customers had its interim price increase been rejected by the Commission. The court in Shutts, Executor viewed these as the fairest interest rates because they were also the rates that petitioner required the royalty owners to meet in their indemnity agreements in order to avoid suspended royalties.

The trial court in the present case applied the rule from Shutts, Executor, and held petitioner liable for prejudgment and postjudgment interest on the suspended royalties, computed at the Commission rates governing petitioner's three price increases. See 18 CFR § 154.102 (1984). The applicable interest rates were: 7% for royalties retained until October 1974; 9% for royalties retained between October 1974 and September 1979; and thereafter at the average prime rate. The trial court did not determine whether any difference existed between the laws of Kansas and other States, or whether another State's laws should be applied to non-Kansas plaintiffs or to royalties from leases in States other than Kansas. 235 Kan., at 221, 679 P. 2d, at 1180.

Petitioner raised two principal claims in its appeal to the Supreme Court of Kansas. It first asserted that the Kansas trial court did not possess personal jurisdiction over absent plaintiff class members as required by International Shoe Co. v. Washington, 326 U. S. 310 (1945), and similar cases. Related to this first claim was petitioner's contention that the "opt-out" notice to absent class members, which forced them to return the request for exclusion in order to avoid the suit, was insufficient to bind class members who were not residents of Kansas or who did not possess "minimum contacts" with Kansas. Second, petitioner claimed that Kansas courts could not apply Kansas law to every claim in the dispute. The trial court should have looked to the laws of each State [803] where the leases were located to determine, on the basis of conflict of laws principles, whether interest on the suspended royalties was recoverable, and at what rate.

The Supreme Court of Kansas held that the entire cause of action was maintainable under the Kansas class-action statute, and the court rejected both of petitioner's claims. 235 Kan. 195, 679 P. 2d 1159 (1984). First, it held that the absent class members were plaintiffs, not defendants, and thus the traditional minimum contacts test of International Shoe did not apply. The court held that nonresident class-action plaintiffs were only entitled to adequate notice, an opportunity to be heard, an opportunity to opt out of the case, and adequate representation by the named plaintiffs. If these procedural due process minima were met, according to the court, Kansas could assert jurisdiction over the plaintiff class and bind each class member with a judgment on his claim. The court surveyed the course of the litigation and concluded that all of these minima had been met.

The court also rejected petitioner's contention that Kansas law could not be applied to plaintiffs and royalty arrangements having no connection with Kansas. The court stated that generally the law of the forum controlled all claims unless "compelling reasons" existed to apply a different law. The court found no compelling reasons, and noted that "[t]he plaintiff class members have indicated their desire to have this action determined under the laws of Kansas." 235 Kan., at 222, 679 P. 2d, at 1181. The court affirmed as a matter of Kansas equity law the award of interest on the suspended royalties, at the rates imposed by the trial court. The court set the postjudgment interest rate on all claims at the Kansas statutory rate of 15%. Id., at 224, 679 P. 2d, at 1183.

I

As a threshold matter we must determine whether petitioner has standing to assert the claim that Kansas did not possess proper jurisdiction over the many plaintiffs in the [804] class who were not Kansas residents and had no connection to Kansas. Respondents claim that a party generally may assert only his own rights, and that petitioner has no standing to assert the rights of its adversary, the plaintiff class, in order to defeat the judgment in favor of the class.

Standing to sue in any Article III court is, of course, a federal question which does not depend on the party's prior standing in state court. Doremus v. Board of Education, 342 U. S. 429, 434 (1952); Baker v. Carr, 369 U. S. 186, 204 (1962). Generally stated, federal standing requires an allegation of a present or immediate injury in fact, where the party requesting standing has "alleged such a personal stake in the outcome of the controversy as to assure that concrete adverseness which sharpens the presentation of issues." Ibid. There must be some causal connection between the asserted injury and the challenged action, and the injury must be of the type "likely to be redressed by a favorable decision." Valley Forge Christian College v. Americans United for Separation of Church and State, Inc., 454 U. S. 464, 472 (1982). See Simon v. Eastern Kentucky Welfare Rights Org., 426 U. S. 26, 41-42 (1976); Arlington Heights v. Metropolitan Housing Dev. Corp., 429 U. S. 252, 261 (1977).

Additional prudential limitations on standing may exist even though the Article III requirements are met because "the judiciary seeks to avoid deciding questions of broad social import where no individual rights would be vindicated and to limit access to the federal courts to those litigants best suited to assert a particular claim." Gladstone, Realtors v. Village of Bellwood, 441 U. S. 91, 99-100 (1979). One of these prudential limits on standing is that a litigant must normally assert his own legal interests rather than those of third parties. See Singleton v. Wulff, 428 U. S. 106 (1976); Craig v. Boren, 429 U. S. 190 (1976).

Respondents claim that petitioner is barred by the rule requiring that a party assert only his own rights; they point out that respondents and petitioner are adversaries and do [805] not have allied interests such that petitioner would be a good proponent of class members' interests. They further urge that petitioner's interference is unneeded because the class members have had opportunity to complain about Kansas' assertion of jurisdiction over their claim, but none have done so. See Singleton, supra, at 113-114.

Respondents may be correct that petitioner does not possess standing jus tertii, but this is not the issue. Petitioner seeks to vindicate its own interests. As a class-action defendant petitioner is in a unique predicament. If Kansas does not possess jurisdiction over this plaintiff class, petitioner will be bound to 28,100 judgment holders scattered across the globe, but none of these will be bound by the Kansas decree. Petitioner could be subject to numerous later individual suits by these class members because a judgment issued without proper personal jurisdiction over an absent party is not entitled to full faith and credit elsewhere and thus has no res judicata effect as to that party. Whether it wins or loses on the merits, petitioner has a distinct and personal interest in seeing the entire plaintiff class bound by res judicata just as petitioner is bound. The only way a class-action defendant like petitioner can assure itself of this binding effect of the judgment is to ascertain that the forum court has jurisdiction over every plaintiff whose claim it seeks to adjudicate, sufficient to support a defense of res judicata in a later suit for damages by class members.

While it is true that a court adjudicating a dispute may not be able to predetermine the res judicata effect of its own judgment, petitioner has alleged that it would be obviously and immediately injured if this class-action judgment against it became final without binding the plaintiff class. We think that such an injury is sufficient to give petitioner standing on its own right to raise the jurisdiction claim in this Court.

Petitioner's posture is somewhat similar to the trust settlor defendant in Hanson v. Denckla, 357 U. S. 235 (1958), who we found to have standing to challenge the forum's personal [806] jurisdiction over an out-of-state trust company which was an indispensable party under the forum State's law. Because the court could not proceed with the action without jurisdiction over the trust company, we observed that "any defendant affected by the court's judgment ha[d] that `direct and substantial personal interest in the outcome' that is necessary to challenge whether that jurisdiction was in fact acquired." Id., at 245, quoting Chicago v. Atchison, T. & S. F. R. Co., 357 U. S. 77 (1958).

II

Reduced to its essentials, petitioner's argument is that unless out-of-state plaintiffs affirmatively consent, the Kansas courts may not exert jurisdiction over their claims. Petitioner claims that failure to execute and return the "request for exclusion" provided with the class notice cannot constitute consent of the out-of-state plaintiffs; thus Kansas courts may exercise jurisdiction over these plaintiffs only if the plaintiffs possess the sufficient "minimum contacts" with Kansas as that term is used in cases involving personal jurisdiction over out-of-state defendants. E. g., International Shoe Co. v. Washington, 326 U. S. 310 (1945); Shaffer v. Heitner, 433 U. S. 186 (1977); World-Wide Volkswagen Corp. v. Woodson, 444 U. S. 286 (1980). Since Kansas had no prelitigation contact with many of the plaintiffs and leases involved, petitioner claims that Kansas has exceeded its jurisdictional reach and thereby violated the due process rights of the absent plaintiffs.

In International Shoe we were faced with an out-of-state corporation which sought to avoid the exercise of personal jurisdiction over it as a defendant by a Washington state court. We held that the extent of the defendant's due process protection would depend "upon the quality and nature of the activity in relation to the fair and orderly administration of the laws . . . ." 326 U. S., at 319. We noted that the Due Process Clause did not permit a State to make a binding judgment against a person with whom the State had no contacts, [807] ties, or relations. Ibid. If the defendant possessed certain minimum contacts with the State, so that it was "reasonable and just, according to our traditional conception of fair play and substantial justice" for a State to exercise personal jurisdiction, the State could force the defendant to defend himself in the forum, upon pain of default, and could bind him to a judgment. Id., at 320.

The purpose of this test, of course, is to protect a defendant from the travail of defending in a distant forum, unless the defendant's contacts with the forum make it just to force him to defend there. As we explained in Woodson, supra, the defendant's contacts should be such that "he should reasonably anticipate being haled" into the forum. 444 U. S., at 297. In Insurance Corp. of Ireland v. Compagnie des Bauxites de Guinee, 456 U. S. 694, 702-703, and n. 10 (1982), we explained that the requirement that a court have personal jurisdiction comes from the Due Process Clause's protection of the defendant's personal liberty interest, and said that the requirement "represents a restriction on judicial power not as a matter of sovereignty, but as a matter of individual liberty." (Footnote omitted.)

Although the cases like Shaffer and Woodson which petitioner relies on for a minimum contacts requirement all dealt with out-of-state defendants or parties in the procedural posture of a defendant, cf. New York Life Ins. Co. v. Dunlevy, 241 U. S. 518 (1916); Estin v. Estin, 334 U. S. 541 (1948), petitioner claims that the same analysis must apply to absent class-action plaintiffs. In this regard petitioner correctly points out that a chose in action is a constitutionally recognized property interest possessed by each of the plaintiffs. Mullane v. Central Hanover Bank & Trust Co., 339 U. S. 306 (1950). An adverse judgment by Kansas courts in this case may extinguish the chose in action forever through res judicata. Such an adverse judgment, petitioner claims, would be every bit as onerous to an absent plaintiff as an adverse judgment on the merits would be to a defendant. [808] Thus, the same due process protections should apply to absent plaintiffs: Kansas should not be able to exert jurisdiction over the plaintiffs' claims unless the plaintiffs have sufficient minimum contacts with Kansas.

We think petitioner's premise is in error. The burdens placed by a State upon an absent class-action plaintiff are not of the same order or magnitude as those it places upon an absent defendant. An out-of-state defendant summoned by a plaintiff is faced with the full powers of the forum State to render judgment against it. The defendant must generally hire counsel and travel to the forum to defend itself from the plaintiff's claim, or suffer a default judgment. The defendant may be forced to participate in extended and often costly discovery, and will be forced to respond in damages or to comply with some other form of remedy imposed by the court should it lose the suit. The defendant may also face liability for court costs and attorney's fees. These burdens are substantial, and the minimum contacts requirement of the Due Process Clause prevents the forum State from unfairly imposing them upon the defendant.

A class-action plaintiff, however, is in quite a different posture. The Court noted this difference in Hansberry v. Lee, 311 U. S. 32, 40-41 (1940), which explained that a "class" or "representative" suit was an exception to the rule that one could not be bound by judgment in personam unless one was made fully a party in the traditional sense. Ibid., citing Pennoyer v. Neff, 95 U. S. 714 (1878). As the Court pointed out in Hansberry, the class action was an invention of equity to enable it to proceed to a decree in suits where the number of those interested in the litigation was too great to permit joinder. The absent parties would be bound by the decree so long as the named parties adequately represented the absent class and the prosecution of the litigation was within the common interest.^[2] 311 U. S., at 41.

[809] Modern plaintiff class actions follow the same goals, permitting litigation of a suit involving common questions when there are too many plaintiffs for proper joinder. Class actions also may permit the plaintiffs to pool claims which would be uneconomical to litigate individually. For example, this lawsuit involves claims averaging about $100 per plaintiff; most of the plaintiffs would have no realistic day in court if a class action were not available.

In sharp contrast to the predicament of a defendant haled into an out-of-state forum, the plaintiffs in this suit were not haled anywhere to defend themselves upon pain of a default judgment. As commentators have noted, from the plaintiffs' point of view a class action resembles a "quasi-administrative proceeding, conducted by the judge." 3B J. Moore & J. Kennedy, Moore's Federal Practice ¶ 23.45 [4.-5] (1984); Kaplan, Continuing Work of the Civil Committee: 1966 Amendments to the Federal Rules of Civil Procedure (I), 81 Harv. L. Rev. 356, 398 (1967).

A plaintiff class in Kansas and numerous other jurisdictions cannot first be certified unless the judge, with the aid of the named plaintiffs and defendant, conducts an inquiry into the common nature of the named plaintiffs' and the absent plaintiffs' claims, the adequacy of representation, the jurisdiction possessed over the class, and any other matters that will bear upon proper representation of the absent plaintiffs' interest. See, e. g., Kan. Stat. Ann. § 60-223 (1983); Fed. Rule Civ. Proc. 23. Unlike a defendant in a civil suit, a class-action plaintiff is not required to fend for himself. See Kan. Stat. Ann. § 60-223(d) (1983). The court and named plaintiffs protect his interests. Indeed, the class-action defendant itself has a great interest in ensuring that the absent plaintiffs' claims are properly before the forum. In this case, for [810] example, the defendant sought to avoid class certification by alleging that the absent plaintiffs would not be adequately represented and were not amendable to jurisdiction. See Phillips Petroleum v. Duckworth, No. 82-54608 (Kan., June 28, 1982).

The concern of the typical class-action rules for the absent plaintiffs is manifested in other ways. Most jurisdictions, including Kansas, require that a class action, once certified, may not be dismissed or compromised without the approval of the court. In many jurisdictions such as Kansas the court may amend the pleadings to ensure that all sections of the class are represented adequately. Kan. Stat. Ann. § 60-223(d) (1983); see also, e. g., Fed. Rule Civ. Proc. 23(d).

Besides this continuing solicitude for their rights, absent plaintiff class members are not subject to other burdens imposed upon defendants. They need not hire counsel or appear. They are almost never subject to counter claims or cross-claims, or liability for fees or costs.^[3] Absent plaintiff class members are not subject to coercive or punitive remedies. Nor will an adverse judgment typically bind an absent plaintiff for any damages, although a valid adverse judgment may extinguish any of the plaintiff's claims which were litigated.

Unlike a defendant in a normal civil suit, an absent class-action plaintiff is not required to do anything. He may sit back and allow the litigation to run its course, content in knowing that there are safeguards provided for his protection. In most class actions an absent plaintiff is provided at least with an opportunity to "opt out" of the class, and if he takes advantage of that opportunity he is removed from the [811] litigation entirely. This was true of the Kansas proceedings in this case. The Kansas procedure provided for the mailing of a notice to each class member by first-class mail. The notice, as we have previously indicated, described the action and informed the class member that he could appear in person or by counsel, in default of which he would be represented by the named plaintiffs and their attorneys. The notice further stated that class members would be included in the class and bound by the judgment unless they "opted out" by executing and returning a "request for exclusion" that was included in the notice.

Petitioner contends, however, that the "opt out" procedure provided by Kansas is not good enough, and that an "opt in" procedure is required to satisfy the Due Process Clause of the Fourteenth Amendment. Insofar as plaintiffs who have no minimum contacts with the forum State are concerned, an "opt in" provision would require that each class member affirmatively consent to his inclusion within the class.

Because States place fewer burdens upon absent class plaintiffs than they do upon absent defendants in nonclass suits, the Due Process Clause need not and does not afford the former as much protection from state-court jurisdiction as it does the latter. The Fourteenth Amendment does protect "persons," not "defendants," however, so absent plaintiffs as well as absent defendants are entitled to some protection from the jurisdiction of a forum State which seeks to adjudicate their claims. In this case we hold that a forum State may exercise jurisdiction over the claim of an absent class-action plaintiff, even though that plaintiff may not possess the minimum contacts with the forum which would support personal jurisdiction over a defendant. If the forum State wishes to bind an absent plaintiff concerning a claim for money damages or similar relief at law,^[4] it must provide minimal [812] procedural due process protection. The plaintiff must receive notice plus an opportunity to be heard and participate in the litigation, whether in person or through counsel. The notice must be the best practicable, "reasonably calculated, under all the circumstances, to apprise interested parties of the pendency of the action and afford them an opportunity to present their objections." Mullane, 339 U. S., at 314-315; cf. Eisen v. Carlisle & Jacquelin, 417 U. S. 156, 174-175 (1974). The notice should describe the action and the plaintiffs' rights in it. Additionally, we hold that due process requires at a minimum that an absent plaintiff be provided with an opportunity to remove himself from the class by executing and returning an "opt out" or "request for exclusion" form to the court. Finally, the Due Process Clause of course requires that the named plaintiff at all times adequately represent the interests of the absent class members. Hansberry, 311 U. S., at 42-43, 45.

We reject petitioner's contention that the Due Process Clause of the Fourteenth Amendment requires that absent plaintiffs affirmatively "opt in" to the class, rather than be deemed members of the class if they do not "opt out." We think that such a contention is supported by little, if any precedent, and that it ignores the differences between class-action plaintiffs, on the one hand, and defendants in nonclass civil suits on the other. Any plaintiff may consent to jurisdiction. Keeton v. Hustler Magazine, Inc., 465 U. S. 770 (1984). The essential question, then, is how stringent the requirement for a showing of consent will be.

We think that the procedure followed by Kansas, where a fully descriptive notice is sent first-class mail to each class member, with an explanation of the right to "opt out," satisfies due process. Requiring a plaintiff to affirmatively [813] request inclusion would probably impede the prosecution of those class actions involving an aggregation of small individual claims, where a large number of claims are required to make it economical to bring suit. See, e. g., Eisen, supra, at 161. The plaintiff's claim may be so small, or the plaintiff so unfamiliar with the law, that he would not file suit individually, nor would he affirmatively request inclusion in the class if such a request were required by the Constitution.^[5] If, on the other hand, the plaintiff's claim is sufficiently large or important that he wishes to litigate it on his own, he will likely have retained an attorney or have thought about filing suit, and should be fully capable of exercising his right to "opt out."

In this case over 3,400 members of the potential class did "opt out," which belies the contention that "opt out" procedures result in guaranteed jurisdiction by inertia. Another 1,500 were excluded because the notice and "opt out" form was undeliverable. We think that such results show that the "opt out" procedure provided by Kansas is by no means pro forma, and that the Constitution does not require more to protect what must be the somewhat rare species of class member who is unwilling to execute an "opt out" form, but whose claim is nonetheless so important that he cannot be presumed to consent to being a member of the class by his failure to do so. Petitioner's "opt in" requirement would require the invalidation of scores of state statutes and of the class-action provision of the Federal Rules of Civil Procedure,^[6] [814] and for the reasons stated we do not think that the Constitution requires the State to sacrifice the obvious advantages in judicial efficiency resulting form the "opt out" approach for the protection of the rara avis portrayed by petitioner.

We therefore hold that the protection afforded the plaintiff class members by the Kansas statute satisfies the Due Process Clause. The interest of the absent plaintiffs are sufficiently protected by the forum State when those plaintiffs are provided with a request for exclusion that can be returned within a reasonable time to the court. See Insurance Corp. of Ireland, 456 U. S., at 702-703, and n. 10. Both the Kansas trial court and the Supreme Court of Kansas held that the class received adequate representation, and no party disputes that conclusion here. We conclude that the Kansas court properly asserted personal jurisdiction over the absent plaintiffs and their claims against petitioner.

III

The Kansas courts applied Kansas contract and Kansas equity law to every claim in this case, notwithstanding that [815] over 99% of the gas leases and some 97% of the plaintiffs in the case had no apparent connection to the State of Kansas except for this lawsuit.^[7] Petitioner protested that the Kansas [816] courts should apply the laws of the States where the leases were located, or at least apply Texas and Oklahoma law because so many of the leases came from those States. The Kansas courts disregarded this contention and found petitioner liable for interest on the suspended royalties as a matter of Kansas law, and set the interest rates under Kansas equity principles.

Petitioner contends that total application of Kansas substantive law violated the constitutional limitations on choice of law mandated by the Due Process Clause of the Fourteenth Amendment and the Full Faith and Credit Clause of Article IV, § 1. We must first determine whether Kansas law conflicts in any material way with any other law which could apply. There can be no injury in applying Kansas law if it is not in conflict with that of any other jurisdiction connected to this suit.

Petitioner claims that Kansas law conflicts with that of a number of States connected to this litigation, especially Texas and Oklahoma. These putative conflicts range from the direct to the tangential, and may be addressed by the Supreme Court of Kansas on remand under the correct constitutional standard. For example, there is no recorded [817] Oklahoma decision dealing with interest liability for suspended royalties: whether Oklahoma is likely to impose liability would require a survey of Oklahoma oil and gas law. Even if Oklahoma found such liability, petitioner shows that Oklahoma would most likely apply its constitutional and statutory 6% interest rate rather than the much higher Kansas rates applied in this litigation. Okla. Const., Art XIV, § 2; Okla. Stat., Tit. 15, § 266 (Supp. 1984-1985); Rendezvous Trails of America, Inc. v. Ayers, 612 P. 2d 1384, 1385 (Okla. App. 1980); Smith v. Robinson, 594 P. 2d 364 (Okla. 1979); West Edmond Hunton Lime Unit v. Young, 325 P. 2d 1047 (Okla. 1958).

Additionally, petitioner points to an Oklahoma statute which excuses liability for interest if a creditor accepts payment of the full principal without a claim for interest, Okla. Stat., Tit. 23, § 8 (1951). Cf. Webster Drilling Co. v. Sterling Oil of Oklahoma, Inc., 376 P. 2d 236 (Okla. 1962). Petitioner contends that by ignoring this statute the Kansas courts created liability that does not exist in Oklahoma.

Petitioner also points out several conflicts between Kansas and Texas law. Although Texas recognizes interest liability for suspended royalties, Texas has never awarded any such interest at a rate greater than 6%, which corresponds with the Texas constitutional and statutory rate.^[8] Tex. Const., Art. 16, § 11; Tex. Rev. Civ. Stat. Ann., Art. 5069-1.03 (Vernon 1971). See Phillips Petroleum Co. v. Stahl Petroleum Co., 569 S. W. 2d 480 (Tex. 1978); Phillips Petroleum Co. v. Adams, 513 F. 2d 355 (CA5), cert. denied, 423 U. S. 930 (1975); cf. Maxey v. Texas Commerce Bank, 580 S. W. 2d 340, 341 (Tex. 1979). Moreover, at least one court interpreting Texas law appears to have held that Texas excuses interest [818] liability once the gas company offers to take an indemnity from the royalty owner and pay him the suspended royalty while the price increase is still tentative. Phillips Petroleum Co. v. Riverside Gas Compression Co., 409 F. Supp. 486, 495-496 (ND Tex. 1976). Such a rule is contrary to Kansas law as applied below, but if applied to the Texas plaintiffs or leases in this case, would vastly reduce petitioner's liability.

The conflicts on the applicable interest rates, alone — which we do not think can be labeled "false conflicts" without a more thoroughgoing treatment than was accorded them by the Supreme Court of Kansas — certainly amounted to millions of dollars in liability. We think that the Supreme Court of Kansas erred in deciding on the basis that it did that the application of its laws to all claims would be constitutional.

Four Terms ago we addressed a similar situation in Allstate Ins. Co. v. Hague, 449 U. S. 302 (1981). In that case we were confronted with two conflicting rules of state insurance law. Minnesota permitted the "stacking" of separate uninsured motorist policies while Wisconsin did not. Although the decedent lived in Wisconsin, took out insurance policies and was killed there, he was employed in Minnesota, and after his death his widow moved to Minnesota for reasons unrelated to the litigation, and was appointed personal representative of his estate. She filed suit in Minnesota courts, which applied the Minnesota stacking rule.

The plurality in Allstate noted that a particular set of facts giving rise to litigation could justify, constitutionally, the application of more than one jurisdiction's laws. The plurality recognized, however, that the Due Process Clause and the Full Faith and Credit Clause provided modest restrictions on the application of forum law. These restrictions required "that for a State's substantive law to be selected in a constitutionally permissible manner, that State must have a significant contact or significant aggregation of contacts, creating state interests, such that choice of its law is neither arbitrary nor fundamentally unfair." Id., at 312-313. The [819] dissenting Justices were in substantial agreement with this principle. Id., at 332 (opinion of POWELL, J., joined by BURGER, C. J., and REHNQUIST, J.). The dissent stressed that the Due Process Clause prohibited the application of law which was only casually or slightly related to the litigation, while the Full Faith and Credit Clause required the forum to respect the laws and judgments of other States, subject to the forum's own interests in furthering its public policy. Id., at 335-336.

The plurality in Allstate affirmed the application of Minnesota law because of the forum's significant contacts to the litigation which supported the State's interest in applying its law. See id., at 313-329. Kansas' contacts to this litigation, as explained by the Kansas Supreme Court, can be gleaned from the opinion below.

Petitioner owns property and conducts substantial business in the State, so Kansas certainly has an interest in regulating petitioner's conduct in Kansas. 235 Kan., at 210, 679 P. 2d, at 1174. Moreover, oil and gas extraction is an important business to Kansas, and although only a few leases in issue are located in Kansas, hundreds of Kansas plaintiffs were affected by petitioner's suspension of royalties; thus the court held that the State has a real interest in protecting "the rights of these royalty owners both as individual residents of [Kansas] and as members of this particular class of plaintiffs." Id., at 211-212, 679 P. 2d, at 1174. The Kansas Supreme Court pointed out that Kansas courts are quite familiar with this type of lawsuit, and "[t]he plaintiff class members have indicated their desire to have this action determined under the laws of Kansas." Id., at 211, 222, 679 P. 2d, at 1174, 1181. Finally, the Kansas court buttressed its use of Kansas law by stating that this lawsuit was analogous to a suit against a "common fund" located in Kansas. Id., at 201, 211-212, 679 P. 2d, at 1168, 1174.

We do not lightly discount this description of Kansas' contacts with this litigation and its interest in applying its law. There is, however, no "common fund" located in Kansas that [820] would require or support the application of only Kansas law to all these claims. See, e. g., Hartford Life Ins. Co. v. Ibs, 237 U. S. 662 (1915). As the Kansas court noted, petitioner commingled the suspended royalties with its general corporate accounts. 235 Kan., at 201, 679 P. 2d, at 1168. There is no specific identifiable res in Kansas, nor is there any limited amount which may be depleted before every plaintiff is compensated. Only by somehow aggregating all the separate claims in this case could a "common fund" in any sense be created, and the term becomes all but meaningless when used in such an expansive sense.

We also give little credence to the idea that Kansas law should apply to all claims because the plaintiffs, by failing to opt out, evinced their desire to be bound by Kansas law. Even if one could say that the plaintiffs "consented" to the application of Kansas law by not opting out, plaintiff's desire for forum law is rarely, if ever controlling. In most cases the plaintiff shows his obvious wish for forum law by filing there. "If a plaintiff could choose the substantive rules to be applied to an action . . . the invitation to forum shopping would be irresistible." Allstate, supra, at 337 (opinion of POWELL, J.). Even if a plaintiff evidences his desire for forum law by moving to the forum, we have generally accorded such a move little or no significance. John Hancock Mut. Life Ins. Co. v. Yates, 299 U. S. 178, 182 (1936); Home Ins. Co. v. Dick, 281 U. S. 397, 408 (1930). In Allstate the plaintiff's move to the forum was only relevant because it was unrelated and prior to the litigation. 449 U. S., at 318-319. Thus the plaintiffs' desire for Kansas law, manifested by their participation in this Kansas lawsuit, bears little relevance.

The Supreme Court of Kansas in its opinion in this case expressed the view that by reason of the fact that it was adjudicating a nationwide class action, it had much greater latitude in applying its own law to the transactions in question than might otherwise be the case:

[821] "The general rule is that the law of the forum applies unless it is expressly shown that a different law governs, and in case of doubt, the law of the forum is preferred.. . . Where a state court determines it has jurisdiction over a nationwide class action and procedural due process guarantees of notice and adequate representation are present, we believe the law of the forum should be applied unless compelling reasons exist for applying a different law. . . . Compelling reasons do not exist to require this court to look to other state laws to determine the rights of the parties involved in this lawsuit." 235 Kan., at 221-222, 679 P. 2d, at 1181.

We think that this is something of a "bootstrap" argument. The Kansas class-action statute, like those of most other jurisdictions, requires that there be "common issues of law or fact." But while a State may, for the reasons we have previously stated, assume jurisdiction over the claims of plaintiffs whose principal contacts are with other States, it may not use this assumption of jurisdiction as an added weight in the scale when considering the permissible constitutional limits on choice of substantive law. It may not take a transaction with little or no relationship to the forum and apply the law of the forum in order to satisfy the procedural requirement that there be a "common question of law." The issue of personal jurisdiction over plaintiffs in a class action is entirely distinct from the question of the constitutional limitations on choice of law; the latter calculus is not altered by the fact that it may be more difficult or more burdensome to comply with the constitutional limitations because of the large number of transactions which the State proposes to adjudicate and which have little connection with the forum.

Kansas must have a "significant contact or significant aggregation of contacts" to the claims asserted by each member of the plaintiff class, contacts "creating state interests," in order to ensure that the choice of Kansas law is not arbitrary [822] or unfair. Allstate, 449 U. S., at 312-313. Given Kansas' lack of "interest" in claims unrelated to that State, and the substantive conflict with jurisdictions such as Texas, we conclude that application of Kansas law to every claim in this case is sufficiently arbitrary and unfair as to exceed constitutional limits.^[9]

When considering fairness in this context, an important element is the expectation of the parties. See Allstate, supra, at 333 (opinion of POWELL, J.). There is no indication that when the leases involving land and royalty owners outside of Kansas were executed, the parties had any idea that Kansas law would control. Neither the Due Process Clause nor the Full Faith and Credit Clause requires Kansas "to substitute for its own [laws], applicable to persons and events within it, the conflicting statute of another state," Pacific Employees Ins. Co. v. Industrial Accident Comm'n, 306 U. S. 493, 502 (1939), but Kansas "may not abrogate the rights of parties beyond its borders having no relation to anything done or to be done within them." Home Ins. Co. v. Dick, supra, at 410.

Here the Supreme Court of Kansas took the view that in a nationwide class action where procedural due process guarantees [823A] of notice and adequate representation were met, "the law of the forum should be applied unless compelling reasons exist for applying a different law." 235 Kan., at 221, 679 P. 2d, at 1181. Whatever practical reasons may have commended this rule to the Supreme Court of Kansas, for the reasons already stated we do not believe that it is consistent with the decisions of this Court. We make no effort to determine for ourselves which law must apply to the various transactions involved in this lawsuit, and we reaffirm our observation in Allstate that in many situations a state court may be free to apply one of several choices of law. But the constitutional limitations laid down in cases such as Allstate and Home Ins. Co. v. Dick, supra, must be respected even in a nationwide class action.

We therefore affirm the judgment of the Supreme Court of Kansas insofar as it upheld the jurisdiction of the Kansas courts over the plaintiff class members in this case, and reverse its judgment insofar as it held that Kansas law was applicable to all of the transactions which it sought to adjudicate. We remand the case to that court for further proceedings not inconsistent with this opinion.

It is so ordered.

JUSTICE POWELL took no part in the decision of this case.

[823B] JUSTICE STEVENS, concurring in part and dissenting in part.

For the reasons stated in Parts I and II of the Court's opinion, I agree that the Kansas courts properly exercised jurisdiction over this class action. I also recognize that the use of the word "compelling" in a portion of the Kansas Supreme Court's opinion, when read out of context, may create an inaccurate impression of that court's choice-of-law holding. See ante, at 821. Our job, however, is to review judgments, not to edit opinions, and I am firmly convinced that there is no constitutional defect in the judgment under review.

As the Court recognizes, there "can be no [constitutional] injury in applying Kansas law if it is not in conflict with that [824] of any other jurisdiction connected to this suit." Ante, at 816. A fair reading of the Kansas Supreme Court's opinion in light of its earlier opinion in Shutts v. Phillips Petroleum Co., 222 Kan. 527, 567 P. 2d 1292 (1977) (hereinafter Shutts I), cert. denied, 434 U. S. 1068 (1978), reveals that the Kansas court has examined the laws of connected jurisdictions and has correctly concluded that there is no "direct" or "substantive" conflict between the law applied by Kansas and the laws of those other States. Cf. ante, at 816, 821-822. Kansas has merely developed general common-law principles to accommodate the novel facts of this litigation — other state courts either agree with Kansas or have not yet addressed precisely similar claims. Consequently, I conclude that the Full Faith and Credit Clause of the Constitution^[10] did not require Kansas to apply the law of any other State, and the Fourteenth Amendment's Due Process Clause^[11] did not prevent Kansas from applying its own law in this case.

The Court errs today because it applies a loose definition of the sort of "conflict" of laws required to state a constitutional claim, allowing Phillips a tactical victory here merely on allegations of "putative" or "likely" conflicts. Ante, at 816, 817. The Court's choice-of-law analysis also treats the two relevant constitutional provisions as though they imposed the same constraints on the forum court. In my view, however, the potential impact of the Kansas choice on the interests of other sovereign States and the fairness of its decision to the litigants should be separately considered. See Allstate Insurance Co. v. Hague, 449 U. S. 302, 320 (1981) (STEVENS, J., concurring in judgment). For both inquiries, it [825] is essential to have a better understanding of the merits of the underlying dispute than can be gleaned from the Court's opinion. I therefore begin with an explanation of the background of this litigation.

I

Petitioner (Phillips) is a large independent producer, purchaser, and seller of natural gas. Beginning in 1954, the prices at which it sold natural gas to interstate pipeline companies were regulated by the Federal Power Commission (Commission).^[12]Phillips Petroleum Co. v. Wisconsin, 347 U. S. 672 (1954). As a party to a large number of producing oil and gas leases, Phillips is obligated to pay a percentage of the value of the production, usually one-eighth, to persons owning an interest in the leased areas, so-called "royalty owners." Some royalty owners are due monthly royalties by contractual agreements made directly with Phillips. See Shutts I, supra, at 532, 567 P. 2d, at 1298. Others are due royalties under contracts made with other gas producers who then sell their gas to Phillips — by separate contract with those producers, Phillips has "assumed the producer's responsibility to distribute the royalties . . . to the royalty owners." 235 Kan. 195, 218, 679 P. 2d 1159, 1178 (1984). The relationship between Phillips and the royalty owners is not regulated by the Commission although it is, of course, materially affected by the Commission's control over the pricing relationship between Phillips and its customers.

In a series of orders entered after 1954, the Commission established a practice of suspending price increases proposed by Phillips until approved by the Commission, but allowing Phillips to collect the higher proposed prices upon the filing by Phillips with the Commission of a corporate undertaking to refund to its customers any portion of an increase [826] that is ultimately disapproved by the Commission. Pursuant to Commission regulation, Phillips agrees that unapproved prices it collects are subject to refund "with interest at seven percent (7%) per annum from the date of receipt until September 18, 1970, and eight percent (8%) per annum thereafter until paid out, if the FPC [does] not approve the sales price." Shutts I, supra, at 533, 567 P. 2d, at 1299 (emphasis deleted) (citing 18 CFR § 154.102(c) (1977) and Commission opinion No. 586, 44 F. P. C. 761, 791 (1970)). Phillips' receipts during periods when its proposed price increases have not yet received final approval therefore include two components — the "firm" proceeds and the "FPC suspense money." For example, while an increase in price from 11 cents per Mcf (thousand cubic feet) to 13 cents is under consideration, the collection of the higher price would include firm proceeds of 11 cents and 2 cents of FPC suspense money.

In July 1961, while a price increase applicable to the tristate Hugoton-Anadarko area (Kansas, Oklahoma, and Texas) was pending, Phillips sent a notice to the royalty owners for that area advising them that "until further notice" they would be paid royalties on the basis of firm proceeds only and that royalties based on suspense money would be paid only after it was "determined that the sums collected are no longer subject to refund." The notice also advised the royalty owners that they could receive ongoing payment of royalties on the suspense money as well if they furnished Phillips with an "acceptable indemnity to cover their proportionate part of any required refunds, plus the required interest." Shutts I, 222 Kan., at 534, 567 P. 2d, at 1299 (emphasis added).^[13] The indemnity which Phillips required was a corporate [827] security bond covering a principal amount based on estimated production for a 2-year period, plus the 7% interest rate Phillips would be required to pay to its customers if the price increase were not approved. Only 17 royalty owners provided Phillips with such an indemnity; approximately 6,400 royalty owners who did not do so did not receive royalties on the suspense proceeds until 11 years later, after the price increase was finally approved. The situation was succinctly summarized by the Kansas Supreme Court in Shutts I:

"From June 1, 1961, to October 1, 1970, Phillips deposited the increased rate monies collected in its general account and commingled it with its other funds, without ever giving notice of this fact to royalty owners during the time it was holding money. It is important to note that during this period of time Phillips had no entitlement to the gas royalty owners' share of the `suspense royalties,' whether or not the rates were approved by the FPC. Phillips never owned this money. While Phillips collected eight-eighths (8/8) of the increased rates, under no condition was the one-eighth (1/8) of the increase attributable to the royalty owners ever to go to Phillips. That royalty share, according to eventual FPC ruling, was either to go to Phillips' royalty owners, or back to Phillips' gas purchasers with interest, or part to one and part to the other." Id., at 535, 567 P. 2d, at 1300 (emphasis in original).

[828] In 1970, the Commission entered an order approving Phillips' Hugoton-Anadarko price increases to the extent of approximately $153,000,000 and disapproving them to the extent of approximately $29,000,000. Thus, over 18% of the suspense money had to be refunded to Phillips' customers, with interest at the rates to which Phillips had agreed under Commission regulation. Having no jurisdiction over the relationship between Phillips and the royalty owners, however, the Commission's order was silent on the subject of royalties on the $153 million of suspense money that did not have to be refunded. After the Commission's order was finally affirmed by the Ninth Circuit in 1972, In re Hugoton-Anadarko Area Rate Case, 466 F. 2d 974, Phillips mailed checks to the royalty owners for their share of the suspense moneys based on the approved higher prices that had been collected since 1961. However, "Phillips neither paid nor offered to pay any interest for the use of the money, nor did Phillips say anything about interest or how long the money had been held or used by Phillips." Shutts I, supra, at 537, 567 P. 2d, at 1301.

The foregoing facts gave rise to Shutts I. This case (Shutts II) involves suspense royalties due on similar price increases approved in 1976, 1977, and 1978 to a larger number of royalty owners (28,100) with interests in leased areas located in 11 States, including Kansas. Otherwise, however, "[w]ith a few exceptions this case is similar in legal issues and factual situation to that presented in Shutts [I]." 235 Kan., at 198, 679 P. 2d, at 1165. Both cases involve what the Kansas Supreme Court has characterized as a "common fund" consisting of the suspense royalties undeniably owed by Phillips [829] but not paid for periods of several years while Commission approval of rate increases were pending.^[14] It is undisputed that Phillips enjoyed the unfettered use of that money. See 222 Kan., at 560, 567 P. 2d, at 1316 (testimony of Phillips' Treasurer). It is also undisputed that when the Commission proceedings ended, none of the money could be retained by Phillips. To the extent that a price increase was disapproved, a refund to the purchasing pipelines, plus interest at the rate set by the Commission, would be required; to the extent that the increases were approved, the money was contractually owned to the royalty owners. As the Kansas court noted: "What is significant is these gas royalty suspense monies never did nor could belong to Phillips." Ibid. (emphasis deleted).^[15]

[830] In Shutts I, the Kansas Supreme Court held that general equitable principles required the award of interest on royalties owned to royalty owners but used by Phillips for a number of years. In support of that conclusion it relied on general statements in two Kansas cases^[16] and a long line of federal cases applying Texas law and concluding that equity requires "the award of interest on suspense royalties under similar circumstances." Id., at 561, 567 P. 2d, at 1317.^[17] The court noted that Oklahoma had no decisions allowing interest on suspense royalties, but concluded that "several Oklahoma decisions hold that interest may be awarded on equitable grounds where necessary to arrive at a fair compensation. (Smith v. Owens, 397 P. 2d 673 [Okla. 1963]; and First Nat. Bank & T. Co. v. Exchange Nat. Bank and T. Co., 517 P. 2d 805 [Okla. App. 1973])."^[18] Finally, the court construed the royalty agreements at issue as containing a "contractual [831] obligation" to pay interest on the royalties "for the period of time the suspense money was held and used by Phillips." Id., at 562, 567 P. 2d, at 1317. Thus the Kansas court also found its result consistent with the only Texas state-court decision on point, Stahl Petroleum Co. v. Phillips Petroleum Co., 550 S. W. 2d 360 (Tex. Civ. App. 1977), which had "awarded interest on suspended royalties" based on "the terms of the royalty agreement . . . rather than unjust enrichment." 222 Kan., at 561, 567 P. 2d, at 1317. Significantly, when the Texas Supreme Court subsequently affirmed the Stahl judgment, it relied on the Kansas Supreme Court's decision in Shutts I to decide that equity as well as contract law requires interest on suspense royalties. Phillips Petroleum Co. v. Stahl Petroleum Co., 569 S. W. 2d 480, 485-488, and n. 5 (1978).

After determining that Phillips was liable for interest on the suspense royalties, the court reversed the trial court's decision that the rate should be 6% because that was the statutory interest rate in Kansas, Oklahoma, and Texas. The Kansas Supreme Court noted that the statutory rate in all three States expressly applied only when no other rate had been agreed upon,^[19] and that in this case Phillips had made an express agreement, evidenced by its corporate undertaking, to pay interest at the rate set by the Commission on suspense moneys found refundable. 222 Kan., at 564, 567 P. 2d, at 1319. The Kansas court therefore declined to apply any State's interest statute, including its own. "[E]quitable principles require, and contractual principles dictate, that the royalty owners receive the same treatment" as refunded purchasers, [832] that is, payment at the same FPC rate of interest.^[20]Id., at 563, 567 P. 2d, at 1318.

Finally, the Kansas Supreme Court rejected Phillips' contention that royalty owners had "waived" their claims to interest by accepting payment of the royalties later or by failing to post an indemnity "acceptable" to Phillips in order to receive contemporaneous payment of suspense royalties. The court noted that the "conditions imposed by Phillips were far more stringent than the corporate undertaking Phillips filed with the FPC," id., at 567, 567 P. 2d, at 1320, and concluded that it was "apparent [that] Phillips' previous imposition of burdensome conditions upon royalty owners . . . was designed to accomplish precisely what the facts disclose. Virtually none of the royalty owners complied with the conditions, thereby leaving the suspense royalties in the hands of Phillips as stakeholder to use at its pleasure . . . ." Id., at 566, 567 P. 2d, at 1320. The court found the rule that "payment of the principal sum is a legal bar to a subsequent action for interest" inapplicable on these facts. Id., at 567, 567 P. 2d, at 1321. Instead, because "payment of [the royalties due] to the plaintiff class members, instead of extinguishing the debt, constituted only a partial payment on an interest-bearing debt[,] [t]his situation invokes application of the so-called `United States Rule,' which provides that in applying partial payments to an interest-bearing debt which is due, in [833] the absence of an agreement or statute to the contrary, the payment should be first applied to the interest due." Ibid.^[21]

In Shutts II, the case now under review, the Kansas Supreme Court adopted its earlier analysis in Shutts I without repeating it. "Although a larger class is involved than in Shutts I, the legal issues presented are substantially the same. While these issues are complex they were thoroughly reviewed in Shutts I." 235 Kan., at 211, 679 P. 2d, at 1174.^[22] Noting that "Phillips has not satisfactorily established why this court should not apply the rule enunciated in Shutts I," the Kansas court went on to state that once jurisdiction over [834] a "nationwide class action" is properly asserted, "the law of the forum should be applied unless compelling reasons exist for applying a different law." Id., at 221, 679 P. 2d, at 1181.

II

This Court, of course, can have no concern with the substantive merits of common-law decisions reached by state courts faithfully applying their own law or the law of another State. When application of purely state law is at issue, "[t]he power delegated to us is for the restraint of unconstitutional [action] by the States, and not for the correction of alleged errors committed by their judiciary." Commercial Bank of Cincinnati v. Buckingham's Executors, 5 How. 317, 343 (1847). The Constitution does not expressly mandate particular or correct choices of law. Rather, a state court's choice of law can invoke constitutional protections, and hence our jurisdiction, only if it contravenes some explicit constitutional limitation.^[23]

Thus it has long been settled that "a mere misconstruction by the forum of the laws of a sister State is not a violation of the Full Faith and Credit Clause." Carroll v. Lanza, 349 U. S. 408, 414, n. 1 (1955) (Frankfurter, J., dissenting).^[24] That Clause requires only that States accord "full faith and credit" to other States' laws — that is, acknowledge the validity and finality of such laws and attempt in good faith to apply them when necessary as they would be applied by home state [835] courts.^[25] But as Justice Holmes explained, when there is "nothing to suggest that [one State's court] was not candidly construing [another State's law] to the best of its ability, . . . even if it was wrong something more than an error of construction is necessary" to invoke the Constitution. Pennsylvania Fire Ins. Co. v. Gold Issue Mining & Milling Co., 243 U. S. 93, 96 (1917).

Merely to state these general principles is to refute any argument that Kansas' decision below violated the Full Faith and Credit Clause. As the opinion in Shutts I indicates, the Kansas court made a careful survey of the relevant laws of Oklahoma and Texas, the only other States whose law is proffered as relevant to this litigation. But, as the Court acknowledges, ante, at 816-818, no other State's laws or judicial decisions were precisely on point, and, in the Kansas court's judgment, roughly analogous Texas and Oklahoma cases supported the results the Kansas court reached. The Kansas court expressly declared that, in a multistate action, a "court should also give careful consideration, as we have attempted to do, to any possible conflict of law problems." 222 Kan., at 557, 567 P. 2d, at 1314.^[26] While a common-law judge might disagree with the substantive legal determinations made by the Kansas court (although nothing in its opinion seems erroneous to me), that court's approach to the possible choices of law evinces precisely the "full faith and credit" that the Constitution requires.

[836] It is imaginable that even a good-faith review of another State's law might still "unjustifiably infring[e] upon the legitimate interests of another State" so as to violate the Full Faith and Credit Clause. Allstate, 449 U. S., at 323 (STEVENS, J., concurring in judgment). If, for example, a Texas oil company or a Texas royalty owner with an interest in a Texas lease were treated directly contrary to a stated policy of the State of Texas by a Kansas court through some honest blunder, the Constitution might bar such "parochial entrenchment" on Texas' interests. Thomas v. Washington Gas Light Co., 448 U. S. 261, 272 (1980) (plurality opinion).^[27] But this case is so distant from such a situation that I need not pursue this theoretical possibility. Even Phillips does not contend that any stated policies of other States have been plainly contravened, and the Court's discussion is founded merely on an absence of reported decisions and the Court's speculation of what Oklahoma or Texas courts might "most likely" do in a case like this. Ante, at 817. There is simply no demonstration here that the Kansas Supreme Court's decision has impaired the legitimate interests of any other States or infringed on their sovereignty in the slightest.

[837] III

It is nevertheless possible for a State's choice of law to violate the Constitution because it is so "totally arbitrary or. . . fundamentally unfair" to a litigant that it violates the Due Process Clause. Allstate, 449 U. S., at 326 (STEVENS, J., concurring in judgment). If the forum court has no connection to the lawsuit other than its jurisdiction over the parties, a decision to apply the forum State's law might so "frustrat[e] the justifiable expectations of the parties" as to be unconstitutional. Id., at 327.^[28]

Again, however, a constitutional claim of "unfair surprise" cannot be based merely upon an unexpected choice of a particular State's law — it must rest on a persuasive showing of an unexpected result arrived at by application of that law. Thus, absent any conflict of laws, in terms of the results they produce, the Due Process Clause simply has not been violated. This is because the underlying theory of a choice-of-law due process claim must be that parties plan their conduct and contractual relations based upon their legitimate expectations [838] concerning the subsequent legal consequences of their actions. For example, they might base a decision on the belief that the law of a particular State will govern. But a change in that State's law in the interim between the execution and the performance of the contract would not violate the Due Process Clause. Nor would the Constitution be violated simply because a state court made an unanticipated ruling on a previously unanswered question of law — perhaps a choice-of-law question.

In this case it is perfectly clear that there has been no due process violation because this is a classic "false conflicts" case.^[29] Phillips has not demonstrated that any significant conflicts exist merely because Oklahoma and Texas state case law is silent concerning the equitable theories developed by the Kansas courts in this litigation, or even because the language of some Oklahoma and Texas statutes suggests that those States would "most likely" reach different results. Ante, at 816-818. The Court's heavy reliance on the characterization of the law provided by Phillips is not an adequate substitute for a neutral review. Ante, at 816, 817 ("Petitioner claims," "petitioner shows," "petitioner points to," "Petitioner also points out . . ."). As is unmistakable from a review of Shutts I, the Kansas Supreme Court has examined the same laws cited by the Court today as indicative of "direct" conflicts, and construed them as supportive of the [839] Kansas result.^[30] Our precedents, to say nothing of the Constitution and our statutory jurisdiction to review state-court judgments, do not permit the Court to second-guess these substantive judgments. Moreover, an independent examination demonstrates solid support for the Kansas court's conclusions.^[31]

[840] The crux of my disagreement with the Court is over the standard applied to evaluate the sufficiency of allegations of choice-of-law conflicts necessary to support a constitutional [841] claim. Rather than potential, "putative," or even "likely" conflicts, I would require demonstration of an unambiguous conflict with the established law of another State as an essential element of a constitutional choice-of-law claim. Arguments that a state court has merely applied general common-law principles in a novel manner, or reconciled arguably [842] conflicting laws erroneously in the face of unprecedented factual circumstances should not suffice to make out a constitutional issue.

In this case, the Kansas Supreme Court's application of general principles of equity, its interpretation of the agreements, its reliance on the Commission's regulations,^[32] and its construction of general statutory terms contravened no established legal principles of other States and consequently cannot be characterized as either arbitrary or fundamentally unfair to Phillips. I therefore can find no due process violation in the Kansas court's decision.^[33]

[843] IV

In final analysis, the Court today may merely be expressing its disagreement with the Kansas Supreme Court's statement that in a "nationwide class action . . . the law of the forum should be applied unless compelling reasons exist for applying a different law." 235 Kan., at 221, 679 P. 2d, at 1181. Considering this statement against the background of the Kansas Supreme Court's careful analysis in Shutts I, however, I am confident that court would agree that every state court has an obligation under the Full Faith and Credit Clause to "respect the legitimate interests of other States and avoid infringement upon their sovereignty." Allstate, 449 U. S., at 322 (STEVENS, J., concurring in judgment); see Nevada v. Hall, 440 U. S. 410, 421, 424, n. 24 (1979).

It is also agreed that "the fact that a choice-of-law decision may be unsound . . . does not necessarily implicate the federal concerns embodied in the Full Faith and Credit Clause." Allstate, 449 U. S., at 323 (STEVENS, J., concurring in judgment); see ante, at 823 ("in many situations a state court may be free to apply one of several choices of law"); Allstate, 449 U. S., at 307 (plurality opinion). When a suit involves claims connected to States other than the forum State, the Constitution requires only that the relevant laws of other States that are brought to the attention of the forum court be examined fairly prior to making a choice of law.^[34] Because this Court "reviews judgments, not opinions," Chevron U. S. A. Inc. v. Natural Resources Defense Council, Inc., 467 U. S. 837, 842 (1984), criticism of a portion of the Kansas [844] court's opinion taken out of context provides an insufficient basis for reversing its judgment. Unless the actual choice of Kansas law violated substantial constitutional rights of the parties, see 28 U. S. C. § 2111, our power to review judgments of state law — including the state law of choice of law — does not extend to reversal based on disagreement with the law's application. A review of the record and the underlying litigation here convincingly demonstrates that, despite Phillips' protestations regarding Kansas' development of common-law principles, no disregard for the laws of other States nor unfair application of Kansas law to the litigants has occurred.^[35] Phillips has no constitutional right to avoid judgment in Kansas because it might have convinced a court in another State to develop its law differently.

I do not believe the Court should engage in detailed evaluations of various States' laws. To the contrary, I believe our limited jurisdiction to review state-court judgments should foreclose such review.^[36] Accordingly, I trust that today's [845] decision is no more than a momentary aberration, and that the Court's opinion will not be read as a decision to constitutionalize novel state-court developments in the common law whenever a litigant can claim that another State connected to the litigation "most likely" would reach a different result. The Court long ago decided that state-court choices of law are unreviewable here absent demonstration of an unambiguous conflict in the established laws of connected States. See n. 15, supra. "To hold otherwise would render it possible to bring to this court every case wherein the defeated party claimed that the statute of another State had been construed to his detriment." Johnson v. New York Life Ins. Co., 187 U. S. 491, 496 (1903). Having ignored this admonition today, the Court may be forced to renew its turn-of-the-century efforts to convince the bar that state-court judgments based on fair evaluations of other States' laws are final.

Accordingly, while I join Parts I and II of the Court's opinion, I respectfully dissent from Part III and from the judgment.

[1] Briefs of amici curiae urging reversal were filed for the Legal Foundation of America by David Crump; and for Amoco Production Co. by Lucas A. Powe, Jr., R. H. Landt, and Glenn D. Young, Jr.

Alan B. Morrison and David C. Vladeck filed a brief for the Public Citizen as amicus curiae urging affirmance.

David B. Kahn filed a brief for the Consumer Coalition as amicus curiae.

[2] The holding in Hansberry, of course, was that petitioners in that case had not a sufficient common interest with the parties to a prior lawsuit such that a decree against those parties in the prior suit would bind the petitioners. But in the present case there is no question that the named plaintiffs adequately represent the class, and that all members of the class have the same interest in enforcing their claims against the defendant.

[3] Petitioner places emphasis on the fact that absent class members might be subject to discovery, counterclaims, cross-claims, or court costs. Petitioner cites no cases involving any such imposition upon plaintiffs, however. We are convinced that such burdens are rarely imposed upon plaintiff class members, and that the disposition of these issues is best left to a case which presents them in a more concrete way.

[4] Our holding today is limited to those class actions which seek to bind known plaintiffs concerning claims wholly or predominantly for money judgments. We intimate no view concerning other types of class actions, such as those seeking equitable relief. Nor, of course, does our discussion of personal jurisdiction address class actions where the jurisdiction is asserted against a defendant class.

[5] In this regard the Reporter for the 1966 amendments to the Federal Rules of Civil Procedure stated:

"[R]equiring the individuals affirmatively to request inclusion in the lawsuit would result in freezing out the claims of people — especially small claims held by small people — who for one reason or another, ignorance, timidity, unfamiliarity with business or legal matters, will simply not take the affirmative step." Kaplan, Continuing Work of the Civil Committee: 1966 Amendments of the Federal Rules of Civil Procedure (I), 81 Harv. L. Rev. 356, 397-398 (1967).

[6] The following statutes or procedural rules permit "opt out" notice in some types of class actions:

Fed. Rule Civ. Proc. 23(c)(2)(A); Ala. Rule Civ. Proc. 23(c)(2)(A); Alaska Rule Civ. Proc. 23(c)(2)(A); Ariz. Rule Civ. Proc. 23(c)(2)(A); Cal. Civ. Code Ann. § 1781(e)(1) (West 1973) (consumer class action); Colo. Rule Civ. Proc. 23(c)(2)(A); Del. Ch. Ct. Rule 23(c)(2)(A); D. C. Super. Ct. Rule Civ. Proc. 23(c)(2)(A); Fla. Rule Civ. Proc. 1.220(d)(2)(A); Idaho Rule Civ. Proc. 23(c)(2)(A); Ind. Rule Trial Proc. 23(C)(2)(A); Iowa Rule Civ. Proc. 42.8(b); Kan. Stat. Ann. § 60-223(c)(2) (1983); Ky. Rule Civ. Proc. 23.03(2)(a); Me. Rule Civ. Proc. 23(c)(2)(A); Md. Rule Civ. Proc. 2-231(e)(1); Mich. Ct. Rule 3.501(C)(5)(b); Minn. Rule Civ. Proc. 23.03 (2)(A); Mo. Rule Civ. Proc. 52.08; Mont. Rule Civ. Proc. 23(c)(2)(A); Nev. Rule Civ. Proc. 23(c)(2)(A); N. J. Civ. Prac. Rule 4:32-2; N. Y. Civ. Prac. Law § 904 (McKinney 1976); N. D. Rule Civ. Proc. 23(g)(2)(B); Ohio Rule Civ. Proc. 23(C)(2)(a); Okla. Stat., Tit. 12, § 2023(C)(2)(a) (Supp. 1984-1985); Ore. Rule Civ. Proc. 32F(1)(b)(ii); Pa. Rule Civ. Proc. 1711(a); Tenn. Rule Civ. Proc. 23.03(2)(a); Vt. Rule Civ. Proc. 23(c)(2)(A); Wash. Ct. Rule 23(C)(2)(i); Wyo. Rule Civ. Proc. 23(c)(2)(A).

OPINION 770_________________________________________________________________________________________________ No. royalty States No. leases Royalties to owners in state state leases in state_________________________________________________________________________________________________Oklahoma ............... 1,430 $ 471,122.53 2,684Texas................... 3,702 2,615,744.46 8,550Kansas.................. 4 115.10 504Arkansas................ 2 552.83 162Louisiana............... 26 516,248.13 361New Mexico.............. 591 194,799.95 469Illinois ............... 1 .01 353Wyloming................ 476 945,441.95 272Mississippi............. ____ ____ 36Utah.................... ____ ____ 18West Virginia........... ____ ____ 22No State Code........... ____ ____ 1,046 _____ __________ 6,232 $4,744,024.10

[7] The Commission approved petitioner's price increases in Opinion Nos. 699, 749 and 770. Petitioner reimbursed royalty owners $3.7, $2.9, and $4.7 million in suspended royalties, respectively. The States where the leases were located and their resident plaintiffs are as follows.

                              OPINION 699_________________________________________________________________________________________________                                                                            No. royalty      States          No. leases    Royalties to   owners                                in state     state leases  in state_________________________________________________________________________________________________Oklahoma ...............          1,266                  $   83,711.35           2,653Texas...................          4,414                     839,152.73           9,591Kansas..................              3                         152.88             496Arkansas................              6                       3,228.22             173Louisiana...............             68                   2,187,548.06           1,244New Mexico..............            941                     433,574.85             621Illinois ...............           ____                           ____             397Wyoming................             690                     148,906.93             413Mississippi.............           ____                           ____              67Utah....................           ____                           ____              29West Virginia...........           ____                           ____              20No State Code...........              1                          [.05]           1,025                                  _____                   ____________                                  7,389                  $3,696,274.97

                            OPINION 749_________________________________________________________________________________________________                                                                             No. royalty       States         No. leases     Royalties to   owners                                in state      state leases  in state_________________________________________________________________________________________________Oklahoma ...............         1,948                   $   243,163.49         3,591Texas...................         3,479                     2,171,217.36         7,881Kansas..................            15                         2,619.24           553Arkansas................            32                         1,769.33           171Louisiana...............           178                       352,539.45           740New Mexico..............           350                        22,670.27           339Illinois ...............             1                             1.30           357Wyloming................            68                        67,570.01            37Mississippi.............             3                           694.93            88Utah....................             1                           184.60            18West Virginia...........            32                        10,364.61           246No State Code...........             2                         1,032.59         1,553                                 ______                   _____________                                 6,109                    $2,873,827.18

[8] The Kansas interest rate also conflicts with the rate which is applicable in Louisiana. At the time this suit was filed that rate was 7%. See La. Civ. Code Ann., Art. 1938 (1977) (amended in 1982); Wurzlow v. Placid Oil Co., 279 So. 2d 749, 772-774 (La. App. 1973) (applying Art. 1938 to oil and gas royalties).

[9] In this case the Kansas Supreme Court held that "[t]he trial court did not determine whether any difference existed between the laws of Kansas and other states or whether another state's law should be applied." 235 Kan. 195, 221, 679 P. 2d 1159, 1180 (1984). Respondents contend that the trial court and the Supreme Court actually incorporated by reference the opinion in Shutts, Executor, 222 Kan. 527, 567 P. 2d 1292 (1977), where the court looked to the Texas and Oklahoma interest rate statutes and found them inapplicable. We do not think that the Kansas Supreme Court fully adopted the choice-of-law discussion in Shutts, Executor as its holding in this case. But even if we agreed that Shutts, Executor was somehow incorporated below, that would be insufficient. Shutts, Executor was a pre-Allstate case involving only 2 other States, rather than the 10 present here. Moreover, the gas region involved in Shutts, Executor was primarily within Kansas borders. Shutts, Executor only considered the conflict involving interest rate liability and state statutes, and in finding the 6% Texas rate inapplicable it cited but did not follow contrary Texas precedent. 222 Kan., at 562-565, 567 P. 2d, at 1317-1319.

[10] "Full Faith and Credit shall be given in each State to the public Acts, Records, and judicial Proceedings of every other State. And the Congress may by general Laws prescribe the Manner in which such Acts, Records and Proceedings shall be proved, and the Effect thereof." U. S. Const., Art. IV, § 1. See also 28 U. S. C. § 1738.

[11] "No State shall . . . deprive any person of life, liberty, or property, without due process of law . . . ." U. S. Const., Amdt. 14, § 1.

[12] The responsibilities of the Federal Power Commission were transferred to the Federal Energy Regulatory Commission in 1977. See 91 Stat. 578, 582-584.

[13]The relevant portion of the 1961 notice provided in full:

"Effective June 1, 1961, and until further notice, royalties paid you will be computed by excluding that portion of any price being collected subject to refund which exceeds 11 [cents] per Mcf (presently the maximum area price level for increased rates as recently announced by the Federal Power Commission in its Statement of General Policy). Payment of royalty based on the balance of the sums collected will be made at such time as it is determined that the sums collected are no longer subject to refund.

"Interest owners desiring to receive payments computed currently on the full sums being collected may arrange to do so by furnishing Phillips Petroleum Company acceptable indemnity to cover their proportionate part of any required refunds, plus the required interest." Shutts I, 222 Kan., at 534, 567 P. 2d, at 1299.

The practice of withholding suspense royalties pending final Commission price approval was sustained in Ashland Oil & Refining Co. v. Staats, Inc., 271 F. Supp. 571, 579 (Kan. 1967), and Boutte v. Chevron Oil Co., 316 F. Supp. 524 (ED La. 1970), aff'd, 442 F. 2d 1337 (CA5 1971) (per curiam).

[14] "Had Phillips put the `suspense royalties' into a common trust fund, separate from its operating funds, to be used solely to pay either the pipeline companies or the gas royalty owners once the FPC ultimately decided the rate increase question, this case would dovetail nicely into the `common fund' cases." Shutts I, 222 Kan., at 552, 567 P. 2d, at 1311. Accord, 235 Kan., at 201, 212, 679 P. 2d, at 1168, 1174. The Court criticizes Kansas' use of the "common fund" concept as applied to these funds. Ante, at 819-820. Kansas is not alone, however, in applying the common fund concept in a class action to a pool of readily identifiable moneys placed within the court's power by a liability determined by the lawsuit itself. See, e. g., Perlman v. First National Bank of Chicago, 15 Ill. App. 3d 784, 799-802, 305 N. E. 2d 236, 247-250 (1973) (cited in Shutts I, 222 Kan., at 553, 567 P. 2d, at 1311-1312); see also Sprague v. Ticonic National Bank, 307 U. S. 161, 166-167 (1939) (common fund may be "recovered" in litigation); Dawson, Lawyers and Involuntary Clients: Attorney Fees From Funds, 87 Harv. L. Rev. 1597, 1615 (1974) ("Funds can also be created by the litigation itself"). Moreover, it is of course no concern of this Court how Kansas chooses to develop its state common-law doctrines. Absent some constitutional foundation plainly lacking here, the Court's criticism of Kansas' substantive state law is entirely gratuitous.

[15] Phillips argued below that some distinction should be made for purposes of interest liability between royalties owed on gas sold to pipeline companies who paid the higher "suspense" price and royalties owned on gas used by Phillips itself rather than sold. Yet "Phillips acknowledges . . . that its obligation to pay royalties under the various . . . contracts exists without regard to the actual disposition of the gas." 235 Kan., at 215, 679 P. 2d, at 1177 (emphasis added). Thus, "[b]y choosing to withhold payment Phillips was allowed the use of the suspense monies during the suspense period which rightfully belonged to the royalty owners, and the royalty owners, in turn, were deprived of receiving and using those monies during that time." Id., at 216, 679 P. 2d, at 1177. Applying the same unjust enrichment theory developed in Shutts I, the Kansas Supreme Court accordingly rejected Phillips' proffered distinction. 235 Kan., at 217, 679 P. 2d, at 1178. Significantly, Phillips does not claim here that even a "putative" conflict of laws might turn on this distinction. Phillips pursues the argument only to contend in a footnote that, because it never actually collected higher prices on gas that it used itself, no "fund" actually existed. Brief for Petitioner 21, n. 18. As the Kansas court noted, however, the fund at issue is the "easily computed" amount of royalties that were due the royalty owners in any case, not the moneys collected by Phillips in return for sales. 235 Kan., at 217, 679 P. 2d, at 1178.

[16] Lightcap v. Mobil Oil Corp., 221 Kan. 448, 562 P. 2d 1, cert. denied, 434 U. S. 876 (1977); Shapiro v. Kansas Public Employees Retirement System, 216 Kan. 353, 357, 532 P. 2d 1081, 1084 (1975).

[17] The court cited six cases, four from the Fifth Circuit and two from the Northern District of Texas, in all of which Phillips was a named party.

[18] The Kansas court also pointed out that "the United States Supreme Court has noted the imposition of interest on refunds ordered by the FPC is not an inappropriate means of preventing unjust enrichment. (United Gas v. Callery Properties, 382 U. S. 223)." 222 Kan., at 562, 567 P. 2d, at 1317-1318.

[19] See Kan. Stat. Ann. § 16-201 (1974) ("Creditors shall be allowed to receive interest at the rate of six percent per annum, when no other rate of interest is agreed upon"); Okla. Stat., Tit. 15, § 266 (1971) ("The legal rate of interest shall be six per cent in the absence of any contract as to the rate of interest"); Tex. Rev. Civ. Stat. Ann., Art. 5069-1.03 (Vernon 1971) ("When no specified rate of interest is agreed upon by the parties, interest at the rate of 6% per annum shall be allowed") (all emphasis added).

[20] The court also held that interest accruing after the entry of judgment should be determined by Kansas' postjudgment interest statute. Kan. Stat. Ann. § 16-204 (1974). Phillips does not and could not contend that the Constitution bars a Kansas court from applying the Kansas postjudgment interest statute to judgments entered by Kansas courts. Such statutes demonstrate an irrefutable state interest in the force carried by judgments entered by a State's own courts. See also Klaxon Co. v. Stentor Electric Mfg. Co., 313 U. S. 487, 498 (1941) (State interest statutes concern "an incidental item of damages, interest, with respect to which courts at the forum have commonly been free to apply their own or some other law as they see fit").

[21] The court noted that the " `United States Rule' is also followed in Oklahoma and Texas," and that Phillips had "raised and lost" its contention of waiver in a similar case in Texas. 222 Kan., at 568, 567 P. 2d, at 1321, citing Phillips Petroleum Co. v. Riverview Gas Compression Co., 409 F. Supp. 486 (ND Tex. 1976). Moreover, because the relevant Oklahoma statute expressly stated that payment of a principal sum must be accepted "as such" to support a finding of waiver, Okla. Stat., Tit. 23, § 8 (1971), the statute was inapplicable here inasmuch as the royalty payments were not so accepted. 222 Kan., at 568, 567 P. 2d, at 1321.

[22] The only apparently new argument raised by Phillips in Shutts II was that it should not be liable for interest to a subclass of the affected royalty owners whose direct contractual agreement for royalties was with other producers who sold their gas to Phillips under a separate agreement. Although Phillips assumed the obligation to pay royalties directly to the royalty owners in these separate agreements, the separate agreements also stated that if a suspended price increase were ultimately approved by the Commission, Phillips would pay the other producers additional money "without interest." Phillips argued that this "without interest" clause barred interest to the royalty owners as well as to the other producers. The Kansas Supreme Court rejected this argument, however, because the royalty owners were not parties to the separate agreements and because no consideration was paid to the royalty owners by Phillips in return for this purported waiver of interest. 235 Kan., at 220, 679 P. 2d, at 1180. "[T]hese provisions, entered into between Phillips and the producers, cannot unilaterally deprive royalty owners of interest which they would otherwise be entitled to receive under casing head gas contracts in which the provisions do not appear." Ibid.

[23] See 28 U. S. C. § 1257: "Final judgments or decrees rendered by the highest court of a State . . . may be reviewed by the Supreme Court . . . (3) [b]y writ of certiorari . . . where any title, right, privilege or immunity is specially set up or claimed under the Constitution" (emphasis added).

[24] This principle was settled in a number of cases decided on either side of the turn of this century. See, e. g., Pennsylvania Fire Ins. Co. v. Gold Issue Mining & Milling Co., 243 U. S. 93, 96 (1917); Western Life Indemnity Co. v. Rupp, 235 U. S. 261, 275 (1914); Louisville & Nashville R. Co. v. Melton, 218 U. S. 36, 51, 52 (1910); Allen v. Alleghany Co., 196 U. S. 458, 464-465 (1905); Johnson v. New York Life Ins. Co., 187 U. S. 491, 496 (1903); Glenn v. Garth, 147 U. S. 360, 367-370 (1893).

[25] Cf. Guaranty Trust Co. v. New York, 326 U. S. 99, 109 (1945) (federal courts should apply state law in furtherance of the goal that "the outcome of the litigation in the federal court should be substantially the same . . . as it would be if tried in a State court").

[26] The Kansas court also stated that Kansas' statutory class-action requirements would "not be fulfilled" if "liability is to be determined according to varying and inconsistent state laws." 222 Kan., at 557, 567 P. 2d, at 1314. This belies any notion that the Kansas court plans to "boot-strap," ante, at 821, its choice-of-law decisions onto its assertion of jurisdiction over multistate actions; precisely the opposite is suggested.

[27] As I noted in Allstate, however, the litigant challenging a court's choice of law clearly "bears the burden of establishing" a constitutional infringement. 449 U. S., at 325, n. 13. "Prima facie every state is entitled to enforce in its own courts its own statutes . . . . One who challenges that right . . . assumes the burden of showing, upon some rational basis, that of the conflicting interests involved those of the foreign state are superior to those of the forum." Alaska Packers Assn. v. Industrial Accident Comm'n, 294 U. S. 532, 547 (1935). See Western Life Indemnity Co. v. Rupp, 235 U. S., at 275 ("It does not appear that the court's attention was called to any decision by the courts of Illinois placing a different construction, or indeed any construction, upon the section in question. If such decision existed, it was incumbent upon defendant to prove it"). Thus, if a litigant has failed to call a state court's attention to relevant law in other jurisdictions, it cannot raise that law here to create a constitutional issue.

[28] I noted in Allstate that choice of forum law might also violate the Due Process Clause in other ways, such as by irrationally favoring residents over nonresidents or representing a "dramatic departure from the rule that obtains in most American jurisdictions." 449 U. S., at 327. The first possibility is not applicable here; all royalty owners were treated exactly alike in the Kansas court's analysis. As for the second possibility, a "dramatic departure" must be distinguished from the application of general equitable principles to address new situations. Phillips may criticize Kansas' allegedly "unique notions of contract and oil and gas law," Brief for Petitioner 33, but such is not a constitutional objection. State courts, like this Court, constantly must apply and develop general legal principles to accommodate novel factual circumstances with the overarching goal of achieving a just result. Today's decision, for example, newly establishes lawful jurisdiction over a multistate plaintiffs' class action that Phillips likely could not have anticipated 15 years ago. Absent some demonstration of a departure from some clear rule obtaining in other States, an argument merely that "[n]o other state ever has hinted" at Kansas' result, id., at 32, is unavailing.

[29] " `[F]alse conflict' really means `no conflict of laws.' If the laws of both states relevant to the set of facts are the same, or would produce the same decision in the lawsuit, there is no real conflict between them." R. Leflar, American Conflicts Law § 93, p. 188 (3d ed. 1977). See also E. Scoles & P. Hay, Conflict of Laws § 2.6, p. 17 (1982) ("A `false conflict' exists when the potentially applicable laws do not differ"). The absence of any direct conflicts here distinguishes this case from decisions such as Home Ins. Co. v. Dick, 281 U. S. 397 (1930), and John Hancock Mutual Life Ins. Co. v. Yates, 299 U. S. 178 (1936), where the interstate legal conflicts were clear, conceded, and dispositive.

[30] In Shutts II the Kansas Supreme Court noted that "the legal issues presented are substantially the same" as in Shutts I, and that "[w]hile these issues are complex they were thoroughly reviewed in Shutts I." 235 Kan., at 211, 679 P. 2d, at 1174. The court then addressed the award and rate of interest as "damages to compensate the plaintiffs for the unjust enrichment derived by Phillips from the use of the plaintiffs' money," and concluded that "[i]n the instant case Phillips has not satisfactorily established why this court should not apply the rule enunciated in Shutts I" respecting this claim. Id., at 221, 679 P. 2d, at 1181. Two sentences later in the same paragraph, the court made the broad statement that its forum law should apply absent "compelling reason." The only fair reading of this statement in context is that the Kansas court in Shutts II adopted its multistate choice-of-law survey performed in Shutts I, and properly placed the burden on Phillips, see n. 18, supra, to show why the Shutts I conclusions should be reexamined. Even if this were ambiguous, this Court should give the Kansas Supreme Court the benefit of the doubt when reviewing its judgment. Thus, I frankly do not understand the Court's summary rejection of that court's attempt to incorporate Shutts I. Ante, at 822, n. 8. As for the implication in that same footnote that the choice-of-law discussion in Shutts I may have been erroneous on the merits, the statement that the Kansas court "did not follow contrary Texas precedent" (emphasis added), is simply wrong. See n. 22, infra.

[31] The Court provides a list of "putative conflicts" ante,at 816-818. The errors and omissions apparent in the Court's discussion demonstrate the dangers of relying on characterizations of state law provided by an interested party.

1. Although there technically may be "no recorded Oklahoma decision dealing with interest liability for suspended royalties," ante, at 816-817 (emphasis added), Oklahoma law expressly provides that the damages "caused by the breach of an obligation to pay money only is deemed to be the amount due by the terms of the obligation, with interest thereon." Okla. Stat., Tit. 23, § 22 (1981) (emphasis added); see also § 6 ("Any person who is entitled to recover damages certain, or capable of being made certain by calculation, . . . is entitled also to recover interest thereon"). The Oklahoma Supreme Court has specifically held that oil field royalty owners may sue as a class to recover royalties due them and may recover interest on the amount of recovery. West Edmond Hunton Line Unit v. Young, 325 P. 2d 1047 (1958).

2. No authority in the Court's string citation regarding Oklahoma's 6% statutory interest rate supports the statement that Oklahoma would "most likely" impose that rate in a suit such as this. Ante, at 817. The constitutional and statutory provisions merely provide that "in the absence of any contract" the rate is indeed 6%. Okla. Stat. Ann., Tit. 15, § 266 (1981). The cited judicial decisions merely hold that interest is recoverable on certain obligations, including royalties due to oil field royalty owners, without discussing applicable limitations on the rate.

After examining these Oklahoma authorities, the Kansas Supreme Court found the Oklahoma statutory rate, as well as that of Texas and Kansas, inapplicable by its own terms, because here Phillips had contractually agreed to the higher federal rate. 235 Kan., at 220-221, 679 P. 2d, at 1180; 222 Kan., at 563-565, 567 P. 2d, at 1318-1319. No reported Oklahoma decision contradicts this judgment, and the express terms of the Oklahoma statute permit it. See also McAnally v. Ideal Federal Credit Union, 428 P. 2d 322, 326 (Okla. 1967) (where federal law provides for interest in excess of 12% per year, that rate "must govern" over Oklahoma statutory rate).

3. The Kansas court similarly reviewed Texas' 6% interest statute and found that Phillips' contractual agreement to the FPC rate rendered the statute inapplicable. 235 Kan., at 220, 679 P. 2d, at 1180; 222 Kan., at 563-565, 567 P. 2d, at 1318-1319. It is true that Texas has not awarded suspense royalty interest at a rate higher than 6% — it is equally plain from the cited cases that no higher rate has been sought. Texas courts have, however, specifically permitted recovery at higher rates when a contract, even an implied or oral contract, evidences agreement to such rates. Preston Farm & Ranch Supply, Inc. v. Bio-Zyme Enterprises, 625 S. W. 2d 295 (Tex. 1981); Moody v. Main Bank of Houston, 667 S. W. 2d 613 (Tex. App. 1984).

4. While noting Phillips' reliance on an Oklahoma statute stating that "accepting payment of the whole principal, as such, waives all claim to interest," Okla. Stat. Ann., Tit. 23, § 8 (1981), the Court itself demonstrates that this statute's application here is open to question, by citing as "cf." Webster Drilling Co. v. Sterling Oil of Okla., Inc., 376 P. 2d 236, 238 (Okla. 1962). In that case, the Oklahoma Supreme Court held that when a right to interest is "based upon a contract, the interest has become `a substantive part of the debt itself,' " and Title 23, § 8, "is not applicable." Id., at 238 (citation omitted). The claim to interest upheld in Webster Drilling was based on an implied contract, exactly as the Kansas Supreme Court found in Shutts I. 222 Kan., at 562, 565, 567 P. 2d, at 1317, 1319. The Kansas Supreme Court explicitly considered Title 23, § 8, and relied on Webster Drilling to find it inapplicable. 222 Kan., at 568, 567 P. 2d, at 1321. It is therefore impossible to suggest, as the Court does, that the Kansas court "ignor[ed]" the Oklahoma statute. Ante, at 817.

5. Finally, the Court plainly misconstrues Texas law by suggesting that a mere "offer" to pay suspended royalties in return for an indemnity agreement would, by itself, excuse interest. In the federal decision cited by the Court, which mentions no Texas cases at the relevant pages, Phillips Petroleum Co. v. Riverside Gas Co., 409 F. Supp., at 495-496, indemnity agreements were actually entered into. Id., at 490. The Fifth Circuit case relied on for authority, which did cite Texas cases, states that an "unconditional offer to give up possession of a disputed fund" is necessary before a bar to interest is created. Phillips Petroleum Co. v. Adams, 513 F. 2d 355, 370 (1975) (emphasis added). The Texas Supreme Court has subsequently agreed that Adams correctly stated Texas law. Phillips Petroleum Co. v. Stahl Petroleum Co., 569 S. W. 2d 480, 487 (1978). See also Fuller v. Phillips Petroleum Co., 408 F. Supp. 643, 646 (ND Tex. 1976) (entering indemnity agreement terminates interest liability because Phillips "lost the reasonably free use of the money"). No indemnity agreements were entered into by the plaintiffs here, however, and as the Kansas Supreme Court found, Phillips' indemnity offer was not "unconditional" — to the contrary, it was "far more stringent than the corporate undertaking Phillips filed with the FPC." 222 Kan., at 567, 567 P. 2d, at 1320. It is also uncontested that Phillips continued to use freely the unpaid suspense royalties long after its "burdensome" conditions were not accepted by the royalty owners. Id., at 566, 567 P. 2d, at 1320. The Court errs drastically by relying on what one Federal District Court "appears" to have held to sustain a constitutional choice-of-law claim.

[32] The fact that the Kansas court rejected its own State's statute in favor of the uniform federal interest rate, to which it found Phillips had contractually agreed, demonstrates the absence of parochialism from its decision. There is absolutely no indication that Texas or Oklahoma courts would have decided differently had the same claim been presented there.

[33] Neither Phillips nor the Court contends that Kansas cannot constitutionally apply its own laws to the claims of Kansas residents, even though the leased land may lie in other States and no other apparent connection to Kansas may exist. Phillips has done business in Kansas throughout the years relevant to this litigation and it seems unarguable that application of Kansas law, or indeed the law of any of the 50 States where royalty owners reside, to the claims of at least some of the plaintiff class members was thus "perceived as possible" by Phillips "at the time of contracting." Allstate, 449 U. S., at 331, n. 24 (STEVENS, J., concurring in judgment); see id., at 316-318, and n. 22. It was also possible, of course, that any number of royalty owners might have moved to Kansas in the years Phillips held their suspense royalties, and that Kansas has a substantial interest in seeing its residents treated fairly when they invoke the jurisdiction of its courts. See Weinberg, Conflicts Cases and the Problem of Relevant Time, 10 Hofstra L. Rev. 1023, 1040-1043 (1982). Because Phillips must have anticipated application of Kansas law to some claims, the eventual geographic distribution of royalty owners' residences goes only to "likelihood" and not to fairness of the application of Kansas law. Allstate, 449 U. S., at 331, n. 24 (STEVENS, J., concurring in judgment). Additionally, it is easy enough for national firms like Phillips to make clear their expectations by placing express choice-of-law clauses in their contracts. See Allstate, 449 U. S., at 318, n. 24; id., at 324, 328 (STEVENS, J., concurring in judgment); Clay v. Sun Ins. Office, Ltd., 377 U. S. 179, 182 (1964). No such clauses are present here, however.

[34] See Allstate, 449 U. S., at 326 (STEVENS, J., concurring in judgment) (footnote omitted): "I question whether a judge's decision to apply the law of his own State could ever be described as wholly irrational. For judges are presumably familiar with their own state law and may find it difficult and time consuming to discover and apply correctly the law of another State. The forum State's interest in fair and efficient administration of justice is therefore sufficient, in my judgment, to attach a presumption of validity to a forum State's decision to apply its own law to a dispute over which it has jurisdiction."

[35] Accord, 3 H. Newberg, Newberg on Class Actions § 13.28, p. 63 (2d ed. 1985) ("the Kansas court in Shutts II may have committed only harmless error in applying its own law because there appears to be no significant conflict of laws among the states involved").

[36] The Court's decision in Allstatehas been criticized on the ground that there may well have been no true conflict of laws present, and, therefore, no need for extended constitutional discussion. See Weintraub, Who's Afraid of Constitutional Limitations on Choice of Law?, 10 Hofstra L. Rev. 17, 18-24 (1981). As I have demonstrated, the Court is once again open to this criticism.

Indeed, unless our review is restricted to cases in which conflicts are unambiguous, the Court will constantly run the risk of misconstruing the common law of any number of States. For example, the Kansas Supreme Court has already decided that Oklahoma would not apply its statutory interest rates where there is evidence of a contractual agreement to a different rate, and that such an agreement is present here. 235 Kan., at 220, 679 P. 2d, at 1180; 222 Kan., at 562-565, 567 P. 2d, at 1318-1319. Yet today the Court speculates that Oklahoma "would most likely apply" its statutory rates in this lawsuit. Ante, at 817. Since this Court has no more authority to resolve such issues of Oklahoma law than does the Kansas Supreme Court, however, the latter court remains free to abide by its former judgment.

Jonathan S. Massey, Washington, DC, for Petitioner.

Christopher M. Curran, Washington, DC, for Respondents.

Jonathan Massey, Massey & Gail LLP, Counsel of Record, Washington, DC, Jim Hood, Attorney General for the State of Mississippi, Geoffrey Morgan, George W. Neville, Office of the Mississippi, Attorney General, Jackson, MS, A. Lee Abraham, Jr., Preston Rideout, Abraham & Rideout, Greenwood, MS, Carolyn G. Anderson, David M. Cialkowski, Patricia A. Bloodgood, June P. Hoidal, Zimmerman Reed PLLP, Minneapolis, MN, for Petitioner.

Martin M. Toto, John H. Chung, Ross E. Elfand, White & Case LLP, New York, NY, Christopher M. Curran, Counsel of Record, Eric Grannon, Kristen J. McAhren, White & Case LLP, Washington, DC, for the Toshiba Respondents, Toshiba Corporation, Toshiba America Information Systems, Inc., Toshiba America Electronic Components, Inc., and Toshiba Mobile Display Co., Ltd.

Charles E. Ross, Michael B. Wallace, Rebecca Hawkins, Wise Carter Child & Caraway, P.A., Jackson, MS, Additional Counsel for the Toshiba Respondents.

Christopher A. Nedeau, Carl L. Blumenstein, Nossaman, LLP, San Francisco, CA, James W. Shelson, Phelps Dunbar LLP, Jackson, MS, for Respondents AU Optronics Corporation and AU Optronics Corporation America.

Robert E. Freitas, Jason S. Angell, Jessica N. Leal, Freitas Tseng & Kaufman LLP, Redwood Shores, CA, for Respondent HannStar Display Corporation.

Christopher B. Hockett, Neal A. Potischman, Davis Polk & Wardwell LLP, Menlo Park, CA, Stephen L. Thomas, Bradley Arant Boult, Cummings LLP, Jackson, MS, for Respondents Chi Mei Corporation, Chimei Innolux Corporation, Chi Mei Optoelectronics USA, Inc., and CMO Japan Co., Ltd.

Stephen B. Kinnaird, Kevin C. McCann, Lee F. Berger, Sean D. Unger, Paul Hastings LLP, Washington, DC, Robert A. Miller, P. Ryan Beckett, Butler, Snow, O'Mara, Stevens and Cannada, PLLC, Ridgeland, MS, Henry L. Parr, Jr., Wyche, P.A., Greenville, SC, for Respondents LG Display Co., Ltd. and LG Display America, Inc.

Robert A. Long, Robert D. Wick, Covington & Burling LLP, Washington, DC, for Respondents Samsung Electronics America, Inc., Samsung Electronics Co., Ltd., and Samsung Semiconductor, Inc.

John M. Grenfell, Jacob R. Sorensen, Pillsbury Winthrop Shaw Pittman LLP, San Francisco, CA, for Respondents Sharp Corporation and Sharp Electronics Corporation.

SOTOMAYOR delivered the opinion of the Court.

Under the Class Action Fairness Act of 2005 (CAFA or Act), defendants in civil suits may remove “mass actions” from state to federal court. CAFA defines a “mass action” as “any civil action ... in which monetary relief claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact.” 28 U.S.C. § 1332(d)(11)(B)(i). The question presented is whether a suit filed by a State as the sole plaintiff constitutes a “mass action” under CAFA where it includes a claim for restitution based on injuries suffered by the State's citizens. We hold that it does not. According to CAFA's plain text, a “mass action” must involve monetary claims brought by 100 or more persons who propose to try those claims jointly as named plaintiffs. Because the State of Mississippi is the only named plaintiff in the instant action, the case must be remanded to state court.

I

A

Congress enacted CAFA in order to “amend the procedures that apply to consideration of interstate class actions.” 119 Stat. 4. In doing so, Congress recognized that “[c]lass action lawsuits are an important and valuable part of the legal system.” CAFA § 2. It was concerned, however, that certain requirements of federal diversity jurisdiction, 28 U.S.C. § 1332<, had functioned to “kee[p] cases of national importance” in state courts rather than federal courts. CAFA § 2.

CAFA accordingly loosened the requirements for diversity jurisdiction for two types of cases—“class actions” and “mass actions.” The Act defines “class action” to mean “any civil action filed under rule 23 of the Federal Rules of Civil Procedure or similar State statute or rule of judicial procedure.” 28 U.S.C. § 1332(d)(1)(B). And it defines “mass action” to mean “any civil action ... in which monetary relief claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact.” § 1332(d)(11)(B)(i).

For class and mass actions, CAFA expanded diversity jurisdiction in two key ways. First, it replaced the ordinary requirement of complete diversity of citizenship among all plaintiffs and defendants, see State Farm Fire & Casualty Co. v. Tashire, 386 U.S. 523, 530–531, 87 S.Ct. 1199, 18 L.Ed.2d 270 (1967), with a requirement of minimal diversity. Under that requirement, a federal court may exercise jurisdiction over a class action if “any member of a class of plaintiffs is a citizen of a State different from any defendant.” § 1332(d)(2)(A). The same rule applies to mass actions. See § 1332(d)(11)(A) ( “[A] mass action shall be deemed ... removable under [§§ 1332(d)(2) through (d)(10) ]”). Second, whereas § 1332(a) ordinarily requires each plaintiff's claim to exceed the sum or value of $75,000, see Exxon Mobil Corp. v. Allapattah Services, Inc., 545 U.S. 546, 554–555, 125 S.Ct. 2611, 162 L.Ed.2d 502 (2005), CAFA grants federal jurisdiction over class and mass actions in which the aggregate amount in controversy exceeds $5 million. §§ 1332(d)(2), (d)(6), (d)(11)(A). Class and mass actions filed in state court that satisfy CAFA's requirements may be removed to federal court, 28 U.S.C. § 1453, but federal jurisdiction in a mass action, unlike a class action, “shall exist only over those plaintiffs” whose claims individually satisfy the $75,000 amount in controversy requirement, § 1332(d)(11)(B)(i).^[1]

B

Respondents manufacture liquid crystal displays, or LCDs. In March 2011, the State of Mississippi sued them in state court, alleging that they had formed an international cartel to restrict competition and raise prices in the LCD market. The State claimed that these actions violated two Mississippi statutes: the Mississippi Antitrust Act, Miss.Code Ann. § 75–21–1 et seq. (2009), and the Mississippi Consumer Protection Act, § 75–24–1 et seq. (2009 and Cum.Supp.2013). The State sought injunctive relief and civil penalties under both statutes, along with punitive damages, costs, and attorney's fees. It also sought restitution for its own purchases “of LCD products and the purchases of its citizens.” App. to Brief in Opposition 65a; § 75–24–11.

Respondents filed a notice to remove the case from state to federal court, arguing that the case was removable under CAFA as either a “class action” or a “mass action.” The District Court ruled that the suit did not qualify as a “class action” because it was “not brought pursuant to Federal Rule of Civil Procedure 23 or a ‘similar State statute or rule of judicial procedure.’ “ 876 F.Supp.2d 758, 769 (S.D.Miss.2012). But it held that the suit did qualify as a “mass action,” because “[i]t is a civil action ‘in which monetary relief claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact.’ Id., at 771. The District Court reached that conclusion on the basis of Fifth Circuit precedent in Louisiana ex rel. Caldwell v. Allstate Ins. Co., 536 F.3d 418 (C.A.5 2008), which it understood to “stan[d] for the proposition that the words ‘persons' and ‘plaintiffs' in [the mass action definition] are to be defined as ‘real parties in interest.’ “ 876 F.Supp.2d, at 771. Applying that rule, the court found that 100 or more unidentified Mississippi consumers had purchased LCD screens and were therefore real parties in interest to the State's restitution claim. Ibid. The court noted the “possibility that a ‘mass action’ should be thought of as a ‘mass joinder,’ “—that is,as a suit involving 100 or more “named plaintiffs.” Ibid., n. 9. But it deemed that interpretation to be foreclosed by Caldwell.

The District Court nonetheless remanded the case to state court on the basis of CAFA's “general public exception,” which excludes from the “mass action” definition “any civil action in which ... all of the claims in the action are asserted on behalf of the general public (and not on behalf of individual claimants or members of a purported class) pursuant to a State statute specifically authorizing such action.” 28 U.S.C. § 1332(d)(11)(B)(ii)(III).

The Court of Appeals reversed. 701 F.3d 796 (C.A.5 2012). It agreed with the District Court's determination that Mississippi's suit is not a “class action” under CAFA.^[2] Id., at 799. It also agreed that, under Caldwell, the suit qualifies as a “mass action” because “[t]he real parties in interest in Mississippi's suit are those more than 100 ... individual citizens who purchased the [LCD] products within Mississippi.” 701 F.3d, at 800. It disagreed, however, with the District Court's ruling that the suit falls within the general public exception. Id., at 802–803.^[3] Judge Elrod concurred in the judgment, noting that after the Fifth Circuit's decision in Caldwell, three Courts of Appeals had deemed similar lawsuits not to be mass actions removable under CAFA.⁴ We granted certiorari to resolve this split of authority, 569 U.S. –––– (2013), and now reverse.

II

A

Our analysis begins with the statutory text. Sebelius v. Cloer, 569 U.S. ––––, –––– (2013) (slip op., at 6). The statute provides:

“[T]he term mass action means any civil action (except a [class action] ) in which monetary relief claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact, except that jurisdiction shall exist only over those plaintiffs whose claims in a mass action satisfy the jurisdictional amount requirements under subsection (a).” § 1332(d)(11)(B)(i).

The parties do not dispute that this provision encompasses suits that are brought jointly by 100 or more named plaintiffs who propose to try their claims together. The question is whether the provision also includes suits brought by fewer than 100 named plaintiffs on the theory that there may be 100 or more unnamed persons who are real parties in interest as beneficiaries to any of the plaintiffs' claims. Respondents argue that the provision covers such suits because “claims of 100 or more persons” refers to “the persons to whom the claim belongs, i.e., the real parties in interest to the claims,” regardless of whether those persons are named or unnamed. Brief for Respondents 19 (emphasis in original). We disagree.

To start, the statute says “100 or more persons,” not “100 or more named or unnamed real parties in interest.” Had Congress intended the latter, it easily could have drafted language to that effect. Indeed, when Congress wanted a numerosity requirement in CAFA to be satisfied by counting unnamed parties in interest in addition to named plaintiffs, it explicitly said so: CAFA provides that in order for a class action to be removable, “the number of members of all proposed plaintiff classes” must be 100 or greater, § 1332(d)(5)(B), and it defines “class members” to mean “the persons (named or unnamed) who fall within the definition of the proposed or certified class,” § 1332(d)(1)(D). Congress chose not to use the phrase “named or unnamed” in CAFA's mass action provision, a decision we understand to be intentional. See Dean v. United States, 556 U.S. 568, 573, 129 S.Ct. 1849, 173 L.Ed.2d 785 (2009) (“ ‘[W]here Congress includes particular language in one section of a statute but omits it in another section of the same Act, it is generally presumed that Congress acts intentionally and purposely in the disparate inclusion or exclusion’ ”).

More fundamentally, respondents' interpretation cannot be reconciled with the fact that the “100 or more persons” referred to in the statute are not unspecified individuals who have no actual participation in the suit, but instead the very “plaintiffs” referred to later in the sentence—the parties who are proposing to join their claims in a single trial. Congress made this understanding evident in two key ways.

First, we presume that “ ‘Congress is aware of existing law when it passes legislation.’ “ Hall v. United States, 566 U.S. ––––, –––– (2012) (slip op., at 9). Here, Congress used the terms “persons” and “plaintiffs” just as they are used in Federal Rule of Civil Procedure 20, governing party joinder. Where § 1332(d)(11)(B)(i) requires that the “claims of 100 or more persons [must be] proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions of law or fact,” Rule 20 provides that “[p]ersons may join in one action as plaintiffs if they assert any right to relief jointly ... and any question of law or fact common to all plaintiffs will arise in the action.” Thus, just as it is used in Rule 20, the term “persons” in § 1332(d)(11)(B)(i) refers to the individuals who are proposing to join as plaintiffs in a single action.

Second, respondents' interpretation of “persons” cannot square with the statute's requirement that the claims of the “100 or more persons” must be proposed for joint trial “on the ground that the plaintiffs' claims involve common questions of law or fact.” § 1332(d)(11)(B)(i). It is difficult to imagine how the claims of one set of unnamed individuals could be proposed for joint trial on the ground that the claims of some completely different group of named plaintiffs share common questions. The better understanding is that Congress meant for the “100 or more persons” and the proposed “plaintiffs” to be one and the same.

Recognizing that the statute's use of the term “persons” could be a reference to proposed plaintiffs, respondents assert that “plaintiffs,” like “persons,” should be construed to “includ[e] both named and unnamed real parties in interest.” Brief for Respondents 24. But that stretches the meaning of “plaintiff” beyond recognition. The term “plaintiff” is among the most commonly understood of legal terms of art: It means a “party who brings a civil suit in a court of law.” Black's Law Dictionary 1267 (9th ed.2009); see also Webster's Third New International Dictionary 1729 (1961) (defining “plaintiff” to mean “one who commences a personal action or lawsuit,” or “the complaining party in any litigation”). It certainly does not mean “anyone, named or unnamed, whom a suit may benefit,” as respondents suggest.^[5]

Moreover, Congress used the term “plaintiffs” twice in the mass action provision. The provision encompasses actions in which monetary “claims of 100 or more persons are proposed to be tried jointly on the ground that the plaintiffs' claims involve common questions,” and it then provides that “jurisdiction shall exist only over those plaintiffs whose claims in a mass action satisfy the jurisdictional amount requiremen[t]” of $75,000. § 1332(d)(11)(B)(i). If respondents are correct that “plaintiffs” means unnamed parties in interest where it is used the first time, then so too the second. After all, the “presumption that a given term is used to mean the same thing throughout a statute” is “at its most vigorous when a term is repeated within a given sentence.” Brown v. Gardner, 513 U.S. 115, 118, 115 S.Ct. 552, 130 L.Ed.2d 462 (1994).

Yet if the term “plaintiffs” is stretched to include all unnamed individuals with an interest in the suit, then § 1332(d)(11)(B)(i)'s requirement that “jurisdiction shall exist only over those plaintiffs whose claims [exceed $75,000]” becomes an administrative nightmare that Congress could not possibly have intended, see Griffin v. Oceanic Contractors, Inc., 458 U.S. 564, 575, 102 S.Ct. 3245, 73 L.Ed.2d 973 (1982). How is a district court to identify the unnamed parties whose claims in a given case are for less than $75,000? Would the court in this case, for instance, have to hold an evidentiary hearing to determine the identity of each of the hundreds of thousands of unnamed Mississippi citizens who purchased one of respondents' LCD products between 1996 and 2006 (the period alleged in the complaint)? Even if it could identify every such person, how would it ascertain the amount in controversy for each individual claim? Respondents suggest that “[i]n some circumstances, defendants may be able to identify from their payment records any persons who may have claims for overpayments,” but they stop notably short of claiming to possess such decades-old records themselves. Brief for Respondents 25.

Furthermore, what would happen with individuals whose claims were valued at less than $75,000? The District Court in this case suggested that if the suit were deemed a mass action, it would sever the claim for “restitution for losses incurred by individuals claiming less than or equal to $75,000 each” and remand that claim back to state court, while allowing the other claims (including the restitution claims exceeding $75,000) to proceed in federal court. 876 F.Supp.2d, at 775. Even respondents do not defend that outcome, presumably because it would mean that much of the State's lawsuit could proceed in state court after all, simultaneously with the newly severed parallel federal action.^[6]

We think it unlikely that Congress intended that federal district courts engage in these unwieldy inquiries. By contrast, interpreting “plaintiffs” in accordance with its usual meaning—to refer to the actual named parties who bring an action—leads to a straightforward, easy to administer rule under which a court would examine whether the plaintiffs have pleaded in good faith the requisite amount. See Horton v. Liberty Mut. Ins. Co., 367 U.S. 348, 353, 81 S.Ct. 1570, 6 L.Ed.2d 890 (1961). Our decision thus comports with the commonsense observation that “when judges must decide jurisdictional matters, simplicity is a virtue.” See Standard Fire Ins. Co. v. Knowles, 568 U.S. ––––, –––– (2013) (slip op., at 6).

B

Our reading of the mass action provision's text is reinforced by the statutory context. See Mohamad v. Palestinian Authority, 566 U.S. ––––, –––– (2012) (slip op., at 5–6).

First, the provision of CAFA governing transfer motions confirms our view that the term “plaintiffs” refers to actual named parties as opposed to unnamed real parties in interest. That provision, § 1332(d)(11)(C)(i), provides that once a mass action has been removed to federal court, it “shall not thereafter be transferred to any other court ... unless a majority of the plaintiffs in the action request transfer.” If respondents are correct that “plaintiffs” means “unnamed parties in interest,” it will be surpassingly difficult for a court to decide in a case like this one whether an action may be transferred. The District Court itself acknowledged this problem, noting that it would have to identify and communicate with “hundreds of thousands if not millions of real parties in interest” to “pol[l] [them] about their preferred forum” if respondents' interpretation were correct. 876 F.Supp.2d, at 777.

The context in which the mass action provision was enacted lends further support to our conclusion. Congress' overriding concern in enacting CAFA was with class actions. See Preamble, 119 Stat. 4 (describing CAFA as an “[a]ct to amend the procedures that apply to consideration of interstate classactions”); CAFA § 2 (Congress' findings with respect to class actions). The mass action provision thus functions largely as a backstop to ensure that CAFA's relaxed jurisdictional rules for class actions cannot be evaded by a suit that names a host of plaintiffs rather than using the class device. Respondents' argument fails to recognize this key distinction. Their position is ultimately that “[t]his action is similar to a class action,” such that it should be removed. Brief for Respondents 27. But if Congress had wanted representative actions brought by States as sole plaintiffs to be removable under CAFA on the theory that they are in substance no different from class actions, it would have done so through the class action provision, not the one governing mass actions.^[7]

III

Rather than relying on the text of CAFA as the source of its real party in interest inquiry, the Court of Appeals appeared to find such an inquiry necessary on the basis of what it understood to be a background principle: that “federal courts look to the substance of the action and not only at the labels that the parties may attach.” Caldwell, 536 F.3d, at 424. This was error.

We have interpreted the diversity jurisdiction statute to require courts in certain contexts to look behind the pleadings to ensure that parties are not improperly creating or destroying diversity jurisdiction. We have held, for example, that a plaintiff may not keep a case out of federal court by fraudulently naming a nondiverse defendant. Wecker v. National Enameling & Stamping Co., 204 U.S. 176, 185–186, 27 S.Ct. 184, 51 L.Ed. 430 (1907). Nor may a plaintiff create diversity by collusively assigning his interest in an action. Kramer v. Caribbean Mills, Inc., 394 U.S. 823, 825–830, 89 S.Ct. 1487, 23 L.Ed.2d 9 (1969); see also 28 U.S.C. § 1359. And in cases involving a State or state official, we have inquired into the real party in interest because a State's presence as a party will destroy complete diversity. Missouri, K. & T.R. Co. v. Missouri Railroad and Warehouse Comm'rs, 183 U.S. 53, 58–59, 22 S.Ct. 18, 46 L.Ed. 78 (1901).

But the question in this case is not simply whether there exists some background principle of analyzing the real parties in interest to a suit; the question is whether Congress intended that courts engage in that analysis when deciding whether a suit is a mass action. Recognizing this fact, respondents do not argue that the real party in interest inquiry employed in the above cases somehow supersedes the text of CAFA; they instead argue that we should read CAFA in light of those cases because “ ‘Congress expects its statutes to be read in conformity with this Court's precedents.’ “ Brief for Respondents 19 (quoting United States v. Wells, 519 U.S. 482, 495, 117 S.Ct. 921, 137 L.Ed.2d 107 (1997)). For two reasons, however, we conclude that Congress did not intend the background inquiry to apply to the mass action provision.

First, it makes sense to infer Congress' intent to incorporate a background principle into a new statute where the principle has previously been applied in a similar manner. But that is not the case here. The background real party in interest inquiry identifies what party's (or parties') citizenship should be considered in determining diversity. The inquiry that respondents urge is quite different: It is an attempt to count up additional unnamed parties in order to satisfy the mass action provision's numerosity requirement. Respondents offer no reason to believe that Congress intended to extend the real party inquiry to this new circumstance, and so any presumption that Congress wanted to incorporate the inquiry, if it exists in this case at all, would be comparatively weak. Cf. Meyer v. Holley, 537 U.S. 280, 286, 123 S.Ct. 824, 154 L.Ed.2d 753 (2003) (“Congress' silence, while permitting an inference that Congress intended to apply ordinary background tort principles, cannot show that it intended to apply an unusual modification of those rules”).^[8]

Second, even if the background principle had previously been applied in the manner sought by respondents, Congress provided express indications that it did not want the principle to apply to the mass action provision. It specified that “the term ‘mass action’ shall not include any civil action in which ... the claims are joined upon motion of a defendant.” § 1332(d)(11)(B)(ii)(II). By prohibiting defendants from joining unnamed individuals to a lawsuit in order to turn it into a mass action, Congress demonstrated its focus on the persons who are actually proposing to join together as named plaintiffs in the suit. Requiring district courts to pierce the pleadings to identify unnamed persons interested in the suit would run afoul of that intent. Moreover, as already discussed, Congress repeatedly used the word “plaintiffs” to describe the 100 or more persons whose claims must be proposed for a joint trial. That word refers to actual, named parties—a concept inherently at odds with the background inquiry into unnamed real parties in interest, who by definition are never plaintiffs. Congress thus clearly displaced a background real party in interest inquiry, even assuming one might otherwise apply. Cf. Barnhart v. Sigmon Coal Co., 534 U.S. 438, 459, n. 16, 122 S.Ct. 941, 151 L.Ed.2d 908 (2002).

For the foregoing reasons, the judgment of the United States Court of Appeals for the Fifth Circuit is reversed, and the case is remanded for further proceedings consistent with this opinion.

It is so ordered.

[1] CAFA provides certain exceptions for class actions that involve matters of principally local or state concern. See 28 U.S.C. §§ 1332(d)(3)-(5). None of them are at issue in this case.

[2] Respondents do not challenge this ruling before this Court.

[3] The Court of Appeals did so on the rationale that because individual Mississippi consumers are real parties in interest to the State's restitution claim, the general public exception's requirement that “all of the claims” must be “asserted on behalf of the general public (and not on behalf of individual claimants)” was not satisfied. 28 U.S.C. § 1332(d)(11)(B)(ii)(III).

[4] See AU Optronics Corp. v. South Carolina, 699 F.3d 385 (C.A.4 2012); Nevada v. Bank of Am. Corp., 672 F.3d 661 (C.A.9 2012); LG Display Co. v. Madigan, 665 F.3d 768 (C.A.7 2011).

[5] Congress could of course require a real party in interest inquiry in a statute that uses the term “plaintiff” simply by saying so. But it has not done that here.

[6] Respondents suggest that a district court might be able to exercise supplemental jurisdiction over the claims that fall beneath $75,000, thereby avoiding the problem of identifying and remanding such claims to the state court. We need not decide the issue here, but we note that at least one Court of Appeals has rejected that view. See Lowery v. Alabama Power Co., 483 F.3d 1184, 1206, n. 51 (C.A.11 2007) (holding that because supplemental jurisdiction does not apply where a federal statute “ ‘expressly provide[s] otherwise,’ “ 28 U.S.C. § 1367(a), the mass action provision's explicit exclusion of jurisdiction over claims beneath $75,000 negates supplemental jurisdiction over such claims).

[7] The parties both point to the “general public exception,” § 1332(d)(11)(B)(ii)(III), in support of their respective positions. But because the foregoing arguments resolve this case, we need not construe that provision here.

[8] We have also applied a real party in interest inquiry in contexts other than that of determining citizenship for purposes of diversity jurisdiction. See North Dakota v. Minnesota, 263 U.S. 365, 374–376, 44 S.Ct. 138, 68 L.Ed. 342 (1923) (state sovereign immunity); Oklahoma ex rel. Johnson v. Cook, 304 U.S. 387, 392–393, 58 S.Ct. 954, 82 L.Ed. 1416 (1938) (original jurisdiction). But even if we were to indulge in a presumption that Congress somehow intended to import the inquiry applied in those particular contexts into the mass action provision's distinct numerosity requirement, we would find any such presumption overridden by CAFA's text.