was correct. Constitutional power is merely the first hurdle that must be overcome in determining that a federal court has jurisdiction over a particular controversy. For the jurisdiction of the federal courts is limited not only by the provisions of Art. III of the Constitution, but also by Acts of Congress. Palmore v. United States, 411 U. S. 389, 401; Lockerty v. Phillips, 319 U. S. 182, 187; Kline v. Burke Constr. Co., 260 U. S. 226, 234; Cary v. Curtis, 3 How. 236, 245.

That statutory law as well as the Constitution may limit a federal court's jurisdiction over nonfederal claims" is well illustrated by two recent decisions of this Court, Aldinger v. Howard, 427 U. S. 1, and Zahn v. International Paper Co., 414 U. S. 291. In Aldinger the Court held that a Federal District Court lacked jurisdiction over a state-law claim against a county, even if that claim was alleged to be pendent to one against county officials under 42 U. S. C. § 1983. In Zahn the Court held that in a diversity class action under Fed. Rule Civ. Proc. 23 (b)(3), the claim of each member of the plaintiff class must independently satisfy the minimum jurisdictional amount set by 28 U. S. C. § 1332 (a), and rejected the argument that jurisdiction existed over those claims that involved $10,000 or less as ancillary to those that involved more. In each case, despite the fact that federal and nonfederal claims arose from a "common nucleus of operative fact," the Court held that the statute conferring jurisdiction over the federal claim did not allow the exercise of jurisdiction over the nonfederal claims."

11 As used in this opinion, the term "nonfederal claim" means one as to which there is no independent basis for federal jurisdiction. Conversely, a "federal claim" means one as to which an independent basis for federal jurisdiction exists.

12 In Monell v. New York City Dept. of Social Services, 436 U. S. 658, we have overruled Monroe v. Pape, 365 U. S. 167, insofar as it held that political subdivisions are never amenable to suit under 42 U. S. C. § 1983-the basis of the holding in Aldinger that 28 U. S. C. § 1343 (3)

The Aldinger and Zahn cases thus make clear that a finding that federal and nonfederal claims arise from a "common nucleus of operative fact," the test of Gibbs, does not end the inquiry into whether a federal court has power to hear the nonfederal claims along with the federal ones. Beyond this constitutional minimum, there must be an examination of the posture in which the nonfederal claim is asserted and of the specific statute that confers jurisdiction over the federal claim, in order to determine whether "Congress in [that statute] has . . . expressly or by implication negated" the exercise of jurisdiction over the particular nonfederal claim. Aldinger v. Howard, supra, at 18.

III

The relevant statute in this case, 28 U. S. C. § 1332 (a)(1), confers upon federal courts jurisdiction over "civil actions where the matter in controversy exceeds the sum or value of $10,000... and is between . . . citizens of different States." This statute and its predecessors have consistently been held to require complete diversity of citizenship.13 That is, diversity jurisdiction does not exist unless each defendant is a citizen of a different State from each plaintiff. Over the years Congress has repeatedly re-enacted or amended the statute conferring diversity jurisdiction, leaving intact this rule of complete diversity." Whatever may have been the original

does not allow pendent jurisdiction of a state-law claim against a county. But Monell in no way qualifies the holding of Aldinger that the jurisdictional questions presented in a case such as this one are statutory as well as constitutional, a point on which the dissenters in Aldinger agreed with the Court. See 427 U. S., at 22 n. 3 (BRENNAN, J., joined by MARSHALL and BLACKMUN, JJ., dissenting).

13 E. g., Strawbridge v. Curtiss, 3 Cranch 267; Coal Co. v. Blatchford, 11 Wall. 172; Indianapolis v. Chase Nat. Bank, 314 U. S. 63, 69; American Fire & Cas. Co. v. Finn, 341 U. S. 6, 17. It is settled that State Farm Fire

complete diversity is not a constitutional requirement. & Cas. Co. v. Tashire, 386 U. S. 523, 530–531.

14 The various Acts are enumerated and described in 1 J. Moore, Federal Practice 0.71 [4] (2d ed. 1977).

purposes of diversity-of-citizenship jurisdiction,15 this subsequent history clearly demonstrates a congressional mandate that diversity jurisdiction is not to be available when any plaintiff is a citizen of the same State as any defendant. Cf. Snyder v. Harris, 394 U. S. 332, 338–339.16

Thus it is clear that the respondent could not originally have brought suit in federal court naming Owen and OPPD as codefendants, since citizens of Iowa would have been on both sides of the litigation. Yet the identical lawsuit resulted when she amended her complaint. Complete diversity was destroyed just as surely as if she had sued Owen initially. In either situation, in the plain language of the statute, the "matter in controversy" could not be "between . . . citizens of different States."

It is a fundamental precept that federal courts are courts of limited jurisdiction. The limits upon federal jurisdiction, whether imposed by the Constitution or by Congress, must be neither disregarded nor evaded. Yet under the reasoning of the Court of Appeals in this case, a plaintiff could defeat the statutory requirement of complete diversity by the simple expedient of suing only those defendants who were of diverse citizenship and waiting for them to implead nondiverse defendants." If, as the Court of Appeals thought, a "common

15 See C. Wright, Law of Federal Courts § 23 (3d ed. 1976), for a discussion of the various theories that have been advanced to explain the constitutional grant of diversity-of-citizenship jurisdiction.

16 Notably, Congress enacted § 1332 as part of the Judicial Code of 1948, 62 Stat. 930, shortly after Rule 14 was amended in 1946. When the Rule was amended, the Advisory Committee noted that "in any case where the plaintiff could not have joined the third party originally because of jurisdictional limitations such as lack of diversity of citizenship, the majority view is that any attempt by the plaintiff to amend his complaint and assert a claim against the impleaded third party would be unavailing." 28 U. S. C. App., p. 7752. The subsequent re-enactment without relevant change of the diversity statute may thus be seen as evidence of congressional approval of that "majority view."

17 This is not an unlikely hypothesis, since a defendant in a tort suit

nucleus of operative fact" were the only requirement for ancillary jurisdiction in a diversity case, there would be no principled reason why the respondent in this case could not have joined her cause of action against Owen in her original complaint as ancillary to her claim against OPPD. Congress' requirement of complete diversity would thus have been evaded completely.

It is true, as the Court of Appeals noted, that the exercise of ancillary jurisdiction over nonfederal claims has often been upheld in situations involving impleader, cross-claims or counterclaims.1 But in determining whether jurisdiction

18

such as this one would surely try to limit his liability by impleading any joint tortfeasors for indemnity or contribution. Some commentators have suggested that the possible abuse of third-party practice could be dealt with under 28 U. S. C. § 1359, which forbids collusive attempts to create federal jurisdiction. See, e. g., 3 J. Moore, Federal Practice 14.27 [1], p. 14-571 (2d ed. 1974); 6 C. Wright & A. Miller, Federal Practice and Procedure § 1444, pp. 231-232 (1971); Note, Rule 14 Claims and Ancillary Jurisdiction, 57 Va. L. Rev. 265, 274-275 (1971). The dissenting opinion today also expresses this view. Post, at 383. But there is nothing necessarily collusive about a plaintiff's selectively suing only those tortfeasors of diverse citizenship, or about the named defendants' desire to implead joint tortfeasors. Nonetheless, the requirement of complete diversity would be eviscerated by such a course of events.

18 The ancillary jurisdiction of the federal courts derives originally from cases such as Freeman v. Howe, 24 How. 450, which held that when federal jurisdiction "effectively controls the property or fund under dispute, other claimants thereto should be allowed to intervene in order to protect their interests, without regard to jurisdiction." Aldinger v. Howard, 427 U. S., at 11. More recently, it has been said to include cases that involve multiparty practice, such as compulsory counterclaims, e. g., Moore v. New York Cotton Exchange, 270 U. S. 593; impleader, e. g., H. L. Peterson Co.. v. Applewhite, 383 F. 2d 430, 433 (CA5); Dery v. Wyer, 265 F. 2d 804 (CA2); cross-claims, e. g., LASA Per L'Industria Del Marmo Soc. Per Azioni v. Alexander, 414 F. 2d 143 (CA6); Scott v. Fancher, 369 F. 2d 842, 844 (CA5); Glen Falls Indemnity Co. v. United States ex rel. Westinghouse Electric Supply Co., 229 F. 2d 370, 373–374 (CA9); or intervention as of right, e. g., Phelps v. Oaks, 117 U. S. 236, 241; Smith Petroleum Service, Inc. v. Monsanto Chemical Co., 420 F. 2d 1103, 1113-1115 (CA5).

over a nonfederal claim exists, the context in which the nonfederal claim is asserted is crucial. See Aldinger v. Howard, 427 U. S., at 14. And the claim here arises in a setting quite different from the kinds of nonfederal claims that have been viewed in other cases as falling within the ancillary jurisdiction of the federal courts.

First, the nonfederal claim in this case was simply not ancillary to the federal one in the same sense that, for example, the impleader by a defendant of a third-party defendant always is. A third-party complaint depends at least in part upon the resolution of the primary lawsuit. See n. 3, supra. Its relation to the original complaint is thus not mere factual similarity but logical dependence. Cf. Moore v. New York Cotton Exchange, 270 U. S. 593, 610. The respondent's claim against the petitioner, however, was entirely separate from her original claim against OPPD, since the petitioner's liability to her depended not at all upon whether or not OPPD was also liable. Far from being an ancillary and dependent claim, it was a new and independent one.

Second, the nonfederal claim here was asserted by the plaintiff, who voluntarily chose to bring suit upon a state-law claim in a federal court. By contrast, ancillary jurisdiction typically involves claims by a defending party haled into court against his will, or by another person whose rights might be irretrievably lost unless he could assert them in an ongoing action in a federal court." A plaintiff cannot complain if ancillary jurisdiction does not encompass all of his possible claims in a case such as this one, since it is he who has chosen the federal rather than the state forum and must thus accept its limitations. "[T]he efficiency plaintiff seeks so avidly is available without question in the state courts." Kenrose Mfg. Co. v. Fred Whitaker Co., 512 F. 2d 890, 894 (CA4).20

19 See n. 18, supra.

20 Whether Iowa's statute of limitations would now bar an action by the respondent in an Iowa court is, of course, entirely a matter of state