Royal Canin U. S. A. v. Wullschleger

(Slip Opinion)              OCTOBER TERM, 2024                                       1

                                       Syllabus

         NOTE: Where it is feasible, a syllabus (headnote) will be released, as is
       being done in connection with this case, at the time the opinion is issued.
       The syllabus constitutes no part of the opinion of the Court but has been
       prepared by the Reporter of Decisions for the convenience of the reader.
       See United States v. Detroit Timber & Lumber Co., 

200 U. S. 321, 337

.


SUPREME COURT OF THE UNITED STATES

                                       Syllabus

                 ROYAL CANIN U. S. A., INC., ET AL. v.
                     WULLSCHLEGER ET AL.

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

    No. 23–677.      Argued October 7, 2024—Decided January 15, 2025
Respondent Anastasia Wullschleger sued petitioner Royal Canin
  U. S. A., Inc., in state court, alleging that Royal Canin had engaged in
  deceptive marketing practices. Her original complaint asserted claims
  based on both federal and state law. Royal Canin removed the case to
  federal court under 

28 U. S. C. §1441

(a). That removal was premised
  on Wullschleger’s federal claim, which gave rise to federal-question ju-
  risdiction and also allowed the federal court to exercise supplemental
  jurisdiction over Wullschleger’s factually intertwined state claims.
  §§1331, 1367. But federal court is not where Wullschleger wanted the
  case to be resolved. So she amended her complaint, deleting every
  mention of federal law, and petitioned the District Court for a remand
  to state court. The District Court denied Wullschleger’s request, but
  the Eighth Circuit reversed. In the Eighth Circuit’s view, Wull-
  schleger’s amendment had eliminated any basis for federal-question
  jurisdiction. And without a federal question, the court concluded,
  there was no possibility of supplemental jurisdiction over Wull-
  schleger’s state-law claims.
Held: When a plaintiff amends her complaint to delete the federal-law
  claims that enabled removal to federal court, leaving only state-law
  claims behind, the federal court loses supplemental jurisdiction over
  the state claims, and the case must be remanded to state court. Pp. 6–
  20.
     (a) Under the text of §1367, the supplemental-jurisdiction statute, a
  post-removal amendment to a complaint that eliminates any basis for
  federal-question jurisdiction also divests a federal court of supple-
  mental jurisdiction over remaining state-law claims. Subsection (a)
  states that “in any civil action of which the district courts have original
2           ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                                   Syllabus

    jurisdiction, the district courts shall have supplemental jurisdiction
    over all other claims that are so related to claims in the action within
    such original jurisdiction that they form part of the same case or con-
    troversy.” The statute thus confers supplemental jurisdiction over
    state-law claims sharing a sufficient factual relationship with the fed-
    eral claims in a case. And in Rockwell Int’l Corp. v. United States, 

549 U. S. 457

, 473–474, this Court held that “when a plaintiff files a com-
    plaint in federal court and then voluntarily amends the complaint,
    courts look to the amended complaint to determine jurisdiction.” So
    under §1367(a), when the plaintiff in an original case amends her com-
    plaint to withdraw the federal claims, leaving only state claims behind,
    she divests the federal court of supplemental jurisdiction. And the re-
    sult must be the same in a removed case, because nothing in §1367(a)’s
    text distinguishes between cases removed to federal court and cases
    originally filed there.
       The exclusion from §1367(a) of such post-amendment state-law
    claims is reflected in the text of §1367(c). Subsection (c) provides that
    a district court “may decline to exercise supplemental jurisdiction”
    over state-law claims covered by §1367(a)’s jurisdictional grant in
    three specific situations where the state-law claims overshadow the
    federal claims in a case. If §1367(a)’s grant of jurisdiction included the
    leftover state claims in an amended complaint, they too would have
    appeared on §1367(c)’s list: Even more than the claims addressed
    there, they are ill-suited to federal adjudication. That §1367(c) makes
    no mention of such claims demonstrates that §1367(a) does not extend
    to them.
       That result accords with Congress’s usual view of how amended
    pleadings can affect jurisdiction. On that view, apparent in varied fed-
    eral statutes, an amendment can wipe the jurisdictional slate clean,
    giving rise to a new analysis with a different conclusion. E.g., §1653
    (“[d]efective allegations of jurisdiction may be amended” so a case can
    come within a federal court’s jurisdiction); §1446(b)(3) (even “if the
    case stated by the initial pleading is not removable,” the defendant can
    remove the case after receiving “an amended pleading” establishing a
    basis for federal jurisdiction); §1332(d)(7) (similar). And just the same
    here: Section 1367 contemplates that when an amended complaint is
    filed, the jurisdictional basis for the suit is reviewed anew. Pp. 7–10.
       (b) That reading of §1367 also parallels a slew of other procedural
    rules linking jurisdiction to the amended, rather than initial, com-
    plaint. In deciding which substantive claims to bring against which
    defendants, a plaintiff can establish—or not—the basis for a federal
    court’s subject-matter jurisdiction. And her control over those matters
    extends beyond the time her first complaint is filed. If a plaintiff
    amends her complaint, the new pleading supersedes the old one and
                     Cite as: 

604 U. S. ____

 (2025)                      3

                                Syllabus

  can bring the suit either newly within or newly outside a federal court’s
  jurisdiction. Thus, as Rockwell explained, if “a plaintiff files a com-
  plaint in federal court and later voluntarily amends the complaint” to
  “withdraw[ ]” the allegations supporting federal jurisdiction, that
  amendment “will defeat jurisdiction” unless the withdrawn allegations
  were “replaced by others” giving the court adjudicatory power. 549
  U. S., at 473–474.
     Rockwell’s rule has a host of variations in both original and removed
  federal cases. Adding federal claims can create original jurisdiction
  where it once was wanting. See, e.g., ConnectU LLC v. Zuckerberg,
  

522 F. 3d 82, 91

. And an amendment can either destroy or create ju-
  risdiction in an original diversity case. See Owen Equipment & Erec-
  tion Co. v. Kroger, 

437 U. S. 365

, 374–377; Newman-Green, Inc. v. Al-
  fonzo-Larrain, 

490 U. S. 826

, 832–833. Similarly, if removing a case
  was improper because the initial complaint did not contain a federal
  claim, the plaintiff’s later assertion of such a claim establishes juris-
  diction going forward. See Pegram v. Herdrich, 

530 U. S. 211

, 215–
  216, and n. 2. And by the same token, amending a complaint in a re-
  moved case to join a non-diverse party destroys diversity jurisdiction,
  and the federal court must remand the case to state court. See
  §1447(e). In removed and original cases alike, the rule that jurisdic-
  tion follows the operative pleading ensures that the case, as it will ac-
  tually be litigated, merits a federal forum. Pp. 10–15.
     (c) Royal Canin contends that this Court has twice before reached
  the opposite conclusion—first, in Carnegie-Mellon Univ. v. Cohill, 

484 U. S. 343

, and next in Rockwell, in a footnote. But in each case, the
  relied-on passage is extraneous to the Court’s holding and reasoning,
  and so cannot bear the weight of Royal Canin’s argument. The footnote
  in Rockwell does state the rule Royal Canin propounds: “[W]hen a de-
  fendant removes a case to federal court based on the presence of a fed-
  eral claim,” it says, “an amendment eliminating the original basis for
  federal jurisdiction generally does not defeat jurisdiction.” 

549 U. S., at 474, n. 6

. But Rockwell was an original federal case, not a removed
  one, so its drive-by assertion of a jurisdictional rule for removed cases
  was entirely outside the issue being decided. That dictum cannot over-
  come the Court’s analysis here or Rockwell’s own core insight that fed-
  eral courts “look to the amended complaint to determine jurisdiction.”
  

Id., at 474

. Pp. 15–20.

75 F. 4th 918

, affirmed.

KAGAN, J., delivered the opinion for a unanimous Court.
                       Cite as: 

604 U. S. ____

 (2025)                              1

                            Opinion of the Court

    NOTICE: This opinion is subject to formal revision before publication in the
    United States Reports. Readers are requested to notify the Reporter of
    Decisions, Supreme Court of the United States, Washington, D. C. 20543,
    pio@supremecourt.gov, of any typographical or other formal errors.


SUPREME COURT OF THE UNITED STATES
                                  _________________

                                  No. 23–677
                                  _________________


 ROYAL CANIN U. S. A., INC., ET AL., PETITIONERS v.
       ANASTASIA WULLSCHLEGER, ET AL.
 ON WRIT OF CERTIORARI TO THE UNITED STATES COURT OF
           APPEALS FOR THE EIGHTH CIRCUIT
                              [January 15, 2025]

   JUSTICE KAGAN delivered the opinion of the Court.
   If a complaint filed in state court asserts federal-law
claims, the defendant may remove the case to federal court.
See 

28 U. S. C. §1441

(a). And if the complaint also asserts
state-law claims arising out of the same facts, the federal
court may adjudicate those claims too, in the exercise of
what is called supplemental jurisdiction. See §1367.
   This case presents a further question: What happens if,
after removal, the plaintiff amends her complaint to delete
all the federal-law claims, leaving nothing but state-law
claims behind? May the federal court still adjudicate the
now purely state-law suit? We hold that it may not. When
an amendment excises the federal-law claims that enabled
removal, the federal court loses its supplemental jurisdic-
tion over the related state-law claims. The case must there-
fore return to state court.
                              I
                              A
  “Federal courts,” we have often explained, “are courts of
limited jurisdiction.” E.g., Kokkonen v. Guardian Life Ins.
Co. of America, 

511 U. S. 375, 377

 (1994). Limited first by
2       ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                      Opinion of the Court

the Constitution, to only the kinds of “Cases” and “Contro-
versies” listed in Article III. And for all lower federal
courts, limited as well by statute. Congress determines,
through its grants of jurisdiction, which suits those courts
can resolve. So, for example, Congress has always given
federal courts power to decide “diversity” cases, between
“citizens of different States” whose dispute involves more
than a stated sum (the so-called amount-in-controversy).
§1332(a). And of special importance here, Congress has
long conferred jurisdiction on federal courts to resolve cases
“arising under” federal law. §1331.
   “Arising under” jurisdiction—more often known as fed-
eral-question jurisdiction—enables federal courts to decide
cases founded on federal law. A suit most typically falls
within that statutory grant “when federal law creates the
cause of action asserted.” Gunn v. Minton, 

568 U. S. 251, 257

 (2013). On rare occasions, the grant also covers a suit
containing state-law claims alone, because one or more of
them “necessarily raise[s]” a “substantial” and “actually
disputed” federal question. 

Id., at 258

. Either way, the de-
termination of jurisdiction is based only on the allegations
in the plaintiff ’s “well-pleaded complaint”—not on any is-
sue the defendant may raise. Franchise Tax Bd. of Cal. v.
Construction Laborers Vacation Trust for Southern Cal.,

463 U. S. 1

, 9–10 (1983). That longstanding rule makes the
complaint—the plaintiff ’s own claims and allegations—the
key to “arising under” jurisdiction. If the complaint pre-
sents no federal question, a federal court may not hear the
suit.
   But if a complaint includes the requisite federal question,
a federal court often has power to decide state-law ques-
tions too. Suppose a complaint with two claims—one based
on federal, the other on state, law. This Court held in Mine
Workers v. Gibbs, 

383 U. S. 715, 725

 (1966), that a federal
court may exercise supplemental jurisdiction over the state
                  Cite as: 

604 U. S. ____

 (2025)             3

                      Opinion of the Court

claim so long as it “derive[s] from” the same “nucleus of op-
erative fact” as the federal one. The Gibbs Court reasoned
that when the two claims are so closely related, they make
up “but one constitutional ‘case’ ”; and the Court presumed
that Congress wanted in that situation to confer jurisdic-
tion up to the Constitution’s limit. 

Ibid.

 (quoting U. S.
Const., Art. III, §2, cl. 1); see Exxon Mobil Corp. v. Allapat-
tah Services, Inc., 

545 U. S. 546, 553

 (2005). Congress later
confirmed that view, generally codifying Gibbs’s supple-
mental-jurisdiction rule in 

28 U. S. C. §1367

 (whose text we
will soon consider, see infra, at 7–8). Under that statute,
as under Gibbs, jurisdiction over a federal-law claim brings
with it supplemental jurisdiction over a state-law claim
arising from the same facts. That derivative jurisdiction,
though, is to some extent discretionary; §1367 spells out cir-
cumstances, again derived from Gibbs, in which a federal
court may decline to hear a state claim falling within the
statute’s bounds. See §1367(c); Gibbs, 383 U. S., at 726–
727.
   And yet one more preparatory point: If a statute confers
federal jurisdiction over a suit, not only the plaintiff but
also the defendant can get it into federal court. Take the
“arising under” statute: It grants federal district courts
“original jurisdiction” over cases presenting a federal ques-
tion. §1331; see §1332 (similarly providing “original juris-
diction” over diversity suits). The plaintiff may avail her-
self of that jurisdiction (and of the opportunity §1367
affords to add supplemental state claims); but she also may
file her suit in state court. If she takes the latter route,
another statute then gives the defendant an option. Be-
cause the case falls within the federal courts’ “original ju-
risdiction,” the defendant may “remove[ ]” it from state to
federal court. §1441(a). And there the case (including sup-
plemental state claims) usually remains. Except that “[i]f
at any time before final judgment it appears that the dis-
trict court lacks subject matter jurisdiction,” the case must
4         ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                          Opinion of the Court

be “remanded” to state court. §1447(c). That is because, to
return to where we started, federal courts are courts of lim-
ited jurisdiction: When they do not have (or no longer have)
authorization to resolve a suit, they must hand it over.
                                B
   Before raising issues demanding a jurisdictional primer,
this case was all about the marketing of dog food. Petitioner
Royal Canin U. S. A., Inc., manufactures a brand of dog
food available only with a veterinarian’s prescription—and
thus sold at a premium price. Respondent Anastasia Wull-
schleger purchased the food, thinking it contained medica-
tion not found in off-the-shelf products. She later learned
it did not. Her suit, initially filed in a Missouri state court,
contends that Royal Canin’s dog food is ordinary dog food:
The company sells the product with a prescription not be-
cause its ingredients make that necessary, but solely to fool
consumers into paying a jacked-up price. Her original com-
plaint asserted claims under the Missouri Merchandising
Practices Act and state antitrust law. It also alleged viola-
tions of the Federal Food, Drug, and Cosmetic Act (FDCA),

21 U. S. C. §301

 et seq.
   And so began the procedural back-and-forth that eventu-
ally landed Wullschleger’s case in this Court. Royal Canin
went first: It removed the case to federal court based on the
asserted violations of the FDCA. 1 That removal properly
——————
  1 That first step provoked an earlier jurisdictional battle, resolved in

favor of allowing removal and not at issue here. The dispute arose be-
cause Wullschleger’s complaint alleged the FDCA violations not as inde-
pendent federal claims, but instead in support of her state claims. Did
the complaint, then, contain the needed federal question? The Court of
Appeals held that it did because the meaning of the referenced FDCA
provisions was thoroughly embedded in, and integral to the success of,
Wullschleger’s state-law claims. See Wullschleger v. Royal Canin
U. S. A., Inc., 

953 F. 3d 519, 522

 (CA8 2020) (citing Gunn v. Minton, 

568 U. S. 251, 258

 (2013)); see supra, at 2. We here treat that finding of fed-
eral-question jurisdiction as a given. And for ease of exposition, we take
                     Cite as: 

604 U. S. ____

 (2025)                   5

                         Opinion of the Court

brought to the District Court not only Wullschleger’s FDCA
claims, but also her factually intertwined state-law claims.
The parties were thus set to litigate the entire suit in fed-
eral court. But that is not where Wullschleger wanted the
case to be resolved. So she countered Royal Canin’s move:
She amended her complaint to delete its every mention of
the FDCA, leaving her state claims to stand on their own.
And with that amended, all-state-law complaint in hand,
she petitioned the District Court to remand the case to state
court.
   Although the District Court denied Wullschleger’s re-
quest, the Court of Appeals for the Eighth Circuit reversed
that decision and ordered a remand. See 

75 F. 4th 918, 924

(2023). 2 In the Eighth Circuit’s view, Wullschleger’s
amendment had eliminated any basis for federal jurisdic-
tion. An amended complaint, the court reasoned, “[super-
sedes] an original complaint and renders the original com-
plaint without legal effect.” 

Id., at 922

 (alteration in
original). And nothing in the amended complaint supported
federal-question jurisdiction: It was, after all, now based
entirely on state law. Nor could the District Court now ex-
ercise supplemental jurisdiction over Wullschleger’s state-
law claims. “[T]he possibility of supplemental jurisdiction,”
the court reasoned, “vanished right alongside the once-
present federal questions.” 

Id., at 924

. And that analysis
held good even though it was Royal Canin, rather than
Wullschleger, that had brought the suit to the District
Court: “It makes no difference,” the Eighth Circuit stated,
that the case “end[ed] up in federal court through removal.”

Id., at 922

.
——————
a slight liberty throughout this opinion, referring to the original com-
plaint’s FDCA allegations simply as federal claims.
  2 Because the denial of a remand request is not immediately appeala-

ble, see Caterpillar Inc. v. Lewis, 

519 U. S. 61, 74

 (1996), the issue
reached the Court of Appeals only after the District Court dismissed
Wullschleger’s amended complaint on the merits.
6         ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                          Opinion of the Court

  Other Courts of Appeals have reached the opposite con-
clusion, holding that a post-removal amendment cannot di-
vest a federal court of jurisdiction. 3 On that view, “[t]he
existence of subject matter jurisdiction is determined by ex-
amining the complaint as it existed at the time of removal.”
Harper v. AutoAlliance Int’l, Inc., 

392 F. 3d 195, 210

 (CA6
2004). So the District Court here would have retained sup-
plemental jurisdiction over Wullschleger’s state-law claims
even after she amended her complaint to delete all her
federal-law ones.
  We granted certiorari to resolve the Circuit split, 

601 U. S. ___

 (2024), and we now affirm the decision below.
                              II
  When a plaintiff amends her complaint following her
suit’s removal, a federal court’s jurisdiction depends on
what the new complaint says. If (as here) the plaintiff elim-
inates the federal-law claims that enabled removal, leaving
only state-law claims behind, the court’s power to decide the
dispute dissolves. With the loss of federal-question juris-
diction, the court loses as well its supplemental jurisdiction
over the state claims. That conclusion fits the text of §1367,
governing supplemental jurisdiction. And it accords with a
bevy of rules hinging federal jurisdiction on the allegations
made in an amended complaint, because that complaint has
become the operative one. Royal Canin argues that our
precedent makes an exception for when an amendment fol-
lows a lawsuit’s removal, but that is to read two bits of gra-
tuitous language for a good deal more than they are worth.



——————
  3 Ching v. Mitre Corp., 

921 F. 2d 11, 13

 (CA1 1990); Collura v. Phila-

delphia, 

590 Fed. Appx. 180, 184

 (CA3 2014) (per curiam); Harless v. CSX
Hotels, Inc., 

389 F. 3d 444, 448

 (CA4 2004); Harper v. AutoAlliance Int’l,
Inc., 

392 F. 3d 195

, 210–211 (CA6 2004); Behlen v. Merrill Lynch, 

311 F. 3d 1087, 1095

 (CA11 2002).
                  Cite as: 

604 U. S. ____

 (2025)             7

                      Opinion of the Court

                             A
  Begin with §1367, entitled “Supplemental jurisdiction.”
Subsection (a) states the basic rule:
    “Except as provided in subsections (b) and (c) or as ex-
    pressly provided otherwise by Federal statute, in any
    civil action of which the district courts have original ju-
    risdiction, the district courts shall have supplemental
    jurisdiction over all other claims that are so related to
    claims in the action within such original jurisdiction
    that they form part of the same case or controversy un-
    der Article III of the United States Constitution.”
The subsection thus takes as its starting point claims
within a federal district court’s original jurisdiction—be-
cause, say, they turn on federal law. See §1331. It then
confers authority on the court to decide certain “other”
claims in the same suit, involving only state law. That
added authority—the court’s supplemental jurisdiction—
extends to claims “so related to” the claims supporting orig-
inal jurisdiction as to form “part of the same [constitutional]
case.” And that needed relationship, Gibbs explains, is one
of fact: The federal court has supplemental jurisdiction over
state-law claims sharing a “common nucleus of operative
fact” with the federal-law ones. 

383 U. S., at 725

; see supra,
at 2–3.
   Skip down a bit and subsection (c) explains that the sup-
plemental jurisdiction just conferred is in some measure
discretionary. That subsection provides that a district
court “may decline to exercise supplemental jurisdiction” in
three specific situations: (1) if the supplemental claim
“raises a novel or complex issue of State law”; (2) if the sup-
plemental claim “substantially predominates” over the
claims within the court’s original jurisdiction; and (3) if the
district court “has dismissed all claims over which it has
8         ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                          Opinion of the Court

original jurisdiction.” 4 In all those contexts, federal law is
not where the real action is. So although supplemental ju-
risdiction persists, the district court need not exercise it: In-
stead, the court may (and indeed, ordinarily should) kick
the case to state court. See Gibbs, 383 U. S., at 726–727.
   In addressing the text of §1367, Royal Canin argues pri-
marily from the first subsection’s grant of jurisdiction. The
language there is “broad,” the company says: Section
1367(a) grants “supplemental jurisdiction over ‘all other
claims’ within the case or controversy, unless Congress ‘ex-
pressly provided otherwise.’ ” Reply Brief 2 (emphasis in
original). And Congress did not expressly provide that an
amendment deleting federal claims eliminates supple-
mental jurisdiction. See id., at 4–5. The upshot, Royal
Canin says, is the rule it espouses: The amendment of a
complaint following removal of a suit to federal court cannot
divest that court of supplemental jurisdiction.
   But that position founders on an undisputed point: Noth-
ing in §1367’s text—including in the text Royal Canin high-
lights—distinguishes between cases removed to federal
court and cases originally filed there. See Tr. of Oral Arg.
7–8. Whatever that text says about removed cases, it also
says about original ones, and vice versa. That means if (as
Royal Canin urges) §1367(a)’s language prevents an
amendment from ousting supplemental jurisdiction in re-
moved cases, then so too it does in original ones. But here
is the rub: In original cases, this Court has already reached
the opposite conclusion. The pertinent rule comes from
Rockwell Int’l Corp. v. United States, 

549 U. S. 457

, 473–
474 (2007): “[W]hen a plaintiff files a complaint in federal
court and then voluntarily amends the complaint, courts
look to the amended complaint to determine jurisdiction.”

——————
   4 A fourth, more general provision, which neither party thinks relevant

here, allows a court to decline supplemental jurisdiction “in exceptional
circumstances,” for “other compelling reasons.” 

28 U. S. C. §1367

(c)(4).
                   Cite as: 

604 U. S. ____

 (2025)              9

                       Opinion of the Court

So when the plaintiff in an original case amends her com-
plaint to withdraw the federal claims, leaving only state
claims behind, she divests the federal court of adjudicatory
power. See 

ibid.

 Royal Canin concedes that result, as it
must. See Tr. of Oral Arg. 6–7. The position it adopts—
applying only in removed cases—is indeed designed not to
collide with Rockwell’s ruling. But once §1367(a) is taken
as consistent with Rockwell, it cannot say what the com-
pany posits. Under that provision—as under Rockwell—an
amendment excising all federal claims divests a court of
supplemental jurisdiction over the remaining state claims
in an original case. And if in an original case, then also in
a removed case—because, again, §1367(a) draws no distinc-
tion between the two.
   The exclusion from §1367(a) of such post-amendment
state-law claims is reflected in the text of §1367(c). Recall
that §1367(c) describes three contexts in which state-law
claims, though covered by §1367(a)’s jurisdictional grant,
are often better given to state courts. See supra, at 7–8. If
§1367(a)’s grant included the leftover state claims in an
amended complaint, they too would have appeared on
§1367(c)’s list: Even more than the claims addressed there,
they are ill-suited to federal adjudication. The leftover
state claims, after all, are now the entirety of the plaintiff ’s
suit. Federal claims are not just subordinate, as in
§§1367(c)(1) and (2), but gone. And gone for good as well.
When federal claims are dismissed by the district court, as
in §1367(c)(3), an appellate court may yet revive them; but
that cannot happen when the plaintiff has excised them
through a proper amendment. So, again, it follows: If
§1367(a) conferred supplemental jurisdiction over the
claims here, §1367(c) would make that jurisdiction discre-
tionary. That §1367(c) does not do so—that even while it
addresses, for example, dismissals of federal claims, it
makes no mention of amendments deleting them—shows
that §1367(a) does not extend so far. Or otherwise said,
10        ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                      Opinion of the Court

there is no discretion to decline supplemental jurisdiction
here because there is no supplemental jurisdiction at all.
Once the plaintiff has ditched all claims involving federal
questions, the leftover state claims are supplemental to
nothing—and §1367(a) does not authorize a federal court to
resolve them.
   That result accords with Congress’s usual view of how
amended pleadings can affect jurisdiction. On that view,
apparent in varied federal statutes, an amendment can
wipe the jurisdictional slate clean, giving rise to a new anal-
ysis with a different conclusion. Consider 

28 U. S. C. §1653

:
It states broadly that, in both trial and appellate courts,
“[d]efective allegations of jurisdiction may be amended” to
ensure that a case can go forward. So a case falling outside
the federal court’s jurisdiction can come within it by virtue
of an amendment. Or take the statute laying out proce-
dures for removal. It provides that even “if the case stated
by the initial pleading is not removable,” an amendment
may make it so: The defendant can remove the case after
receiving “an amended pleading” establishing that the case
is newly subject to federal jurisdiction. §1446(b)(3); see
§1332(d)(7) (similarly providing that an “amended com-
plaint” in a proposed class action may create “[f]ederal ju-
risdiction”). In such statutes, Congress conceives of amend-
ments as having the potential to alter jurisdiction. And just
the same here. Section 1367 contemplates that when an
amended complaint is filed, the jurisdictional basis for the
suit is reviewed anew. If nothing in the amended complaint
now falls “within [the federal court’s] original jurisdiction,”
then neither does anything fall within the court’s “supple-
mental jurisdiction.” §1367(a). In the superseding plead-
ing, the state-law claims are just state-law claims, outside
§1367(a)’s purview.
                             B
     That reading of §1367 also parallels a slew of other,
                  Cite as: 

604 U. S. ____

 (2025)           11

                      Opinion of the Court

mainly judge-made procedural rules linking jurisdiction to
the amended, rather than initial, complaint. In multiple
contexts—involving both cases brought in federal court and
cases removed there—courts conceive of amendments to
pleadings as potentially jurisdiction-changing events. The
amended complaint becomes the operative one; and in tak-
ing the place of what has come before, it can either create
or destroy jurisdiction. Section 1367, as laid out above, fits
hand in glove with—indeed, embodies—that familiar ap-
proach. A post-removal amendment can divest a federal
court of its supplemental jurisdiction because—as the usual
procedural principle holds—jurisdiction follows from (and
only from) the operative pleading.
   Begin from the beginning: The plaintiff is “the master of
the complaint,” and therefore controls much about her suit.
Caterpillar Inc. v. Williams, 

482 U. S. 386

, 398–399 (1987).
She gets to determine which substantive claims to bring
against which defendants. And in so doing, she can estab-
lish—or not—the basis for a federal court’s subject-matter
jurisdiction. She may, for example, name only defendants
who come from a different State, or instead add one from
her own State and thereby destroy diversity of citizenship.
See §1332(a). Or in cases like this one, she may decide to
plead federal-law claims, or instead to allege state-law
claims alone and thus ensure a state forum. See §1331; su-
pra, at 2 (describing the well-pleaded complaint rule).
   And the plaintiff ’s control over those matters extends be-
yond the time her first complaint is filed. If a plaintiff
amends her complaint, the new pleading “supersedes” the
old one: The “original pleading no longer performs any func-
tion in the case.” 6 C. Wright, A. Miller, & M. Kane, Federal
Practice and Procedure §1476, pp. 636–637 (3d ed. 2010).
Or as we put the matter over a century ago: “When a peti-
tion is amended,” the “cause proceeds on the amended peti-
tion.” Washer v. Bullitt County, 

110 U. S. 558, 562

 (1884).
12        ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                          Opinion of the Court

So changes in parties, or changes in claims, effectively re-
make the suit. And that includes its jurisdictional basis:
The reconfiguration accomplished by an amendment may
bring the suit either newly within or newly outside a federal
court’s jurisdiction.
   That idea is the one Rockwell invoked, as earlier noted.
See supra, at 8–9. Recall the situation there considered:
“[A] plaintiff files a complaint in federal court and later vol-
untarily amends the complaint” to “withdraw[ ]” the allega-
tions supporting federal jurisdiction. Rockwell, 549 U. S.,
at 473–474. Should the suit proceed? “[C]ourts,” Rockwell
replied, “look to the amended complaint to determine juris-
diction.” Id., at 474. That complaint is now the operative
one; the old complaint has become irrelevant. So unless the
withdrawn allegations were “replaced by others” giving the
court adjudicatory power, the plaintiff ’s amendment “will
defeat jurisdiction.” Id., at 473. Or more specifically: If a
plaintiff files a suit in federal court based on federal claims
and later scraps those claims, the federal court cannot go
forward with a now all-state-claim suit. See id., at 473–
474. 5
   That rule for original federal cases has a host of varia-
tions, each tying jurisdiction to an amended pleading. If, as
Rockwell spelled out, eliminating federal claims in such a
suit can destroy federal jurisdiction, the opposite is also
true: Adding federal claims can create federal jurisdiction
where it once was wanting. See, e.g., ConnectU LLC v.
——————
   5 The Rockwell Court distinguished its rule from another, operating in

diversity cases, which evaluates a party’s citizenship (e.g., whether the
defendant is in fact from New York) at the time a suit is brought, and
never again later. See 

549 U. S., at 473

 (citing, e.g., Anderson v. Watt,

138 U. S. 694, 701

 (1891)). That so-called time-of-filing rule, Rockwell
explained, concerns only the actual “state of things” relevant to jurisdic-
tion—meaning, the facts on the ground, rather than (as addressed here)
the claims and parties that the plaintiff includes in a complaint. 

549 U. S., at 473

; see 

75 F. 4th 918

, 922–923 (CA8 2023) (case below) (dis-
cussing that distinction).
                      Cite as: 

604 U. S. ____

 (2025)                     13

                           Opinion of the Court

Zuckerberg, 

522 F. 3d 82

, 91 (CA1 2008) (holding that an
amended complaint, which “replaced the original complaint
lock, stock, and barrel,” conferred jurisdiction). And so too,
an amendment can either destroy or create jurisdiction in
an original diversity case. The addition of a non-diverse
party in such a case typically destroys diversity jurisdiction,
requiring the case’s dismissal. See Owen Equipment &
Erection Co. v. Kroger, 

437 U. S. 365

, 374–377 (1978) (stat-
ing that an amendment asserting claims against a non-
diverse party “destroy[s]” complete diversity “just as surely
as” joining that party in the first instance); see also, e.g.,
American Fiber & Finishing, Inc. v. Tyco Healthcare Group,
LP, 

362 F. 3d 136, 139

 (CA1 2004). 6 Conversely, the elimi-
nation of a non-diverse defendant by way of amendment en-
sures that a case can proceed in federal court, though it
could not have done so before. See Newman-Green, Inc. v.
Alfonzo-Larrain, 

490 U. S. 826

, 832–833 (1989). In short,
the rule in original cases that jurisdiction follows the
amended (i.e., now operative) pleading applies across the
board.
  And still more: Similar rules have long applied in the re-
moval context. Not across the board, of course, else this
case would not have arisen: The very issue here is whether,
in a removed case (as in an original one), an amended com-
plaint dropping federal claims destroys jurisdiction. But in
two of the other situations discussed above, the rule in re-
moved cases is the same as the rule in original ones. 7 First,
——————
   6 That general rule does not apply when an amendment merely substi-

tutes a successor-in-interest for the first-named defendant. In that situ-
ation, the former steps into the latter’s shoes, and the diversity jurisdic-
tion founded on the initial complaint thus continues. See Freeport-
McMoRan Inc. v. K N Energy, Inc., 

498 U. S. 426

, 428–429 (1991) (per
curiam).
   7 To our knowledge, no appellate decision addresses whether in the fi-

nal situation discussed—when an amendment eliminates a non-diverse
party—the rule in removed cases similarly follows the rule in original
cases.
14        ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                           Opinion of the Court

in removed cases too, amending a complaint to add a federal
claim creates federal jurisdiction when it did not previously
exist. So even if removing a case was improper because the
initial complaint did not contain a federal claim, the plain-
tiff ’s later assertion of such a claim establishes jurisdiction
going forward. See Pegram v. Herdrich, 

530 U. S. 211

, 215–
216, and n. 2 (2000); Bernstein v. Lind-Waldock & Co., 

738 F. 2d 179

, 185–186 (CA7 1984) (Posner, J.). The federal
court can thus resolve both the newly added federal-law
claim and the now supplemental state-law ones. See 

id.,

 at
186–187. And second, in removed cases too, amending a
complaint to join a non-diverse party destroys diversity ju-
risdiction. So if such a joinder occurs after removal, the fed-
eral court must remand the case to the state court it began
in. See §1447(e); Powerex Corp. v. Reliant Energy Services,
Inc., 

551 U. S. 224

, 231–232 (2007). Once again, federal ju-
risdiction—or its absence—follows from the amended com-
plaint. 8
——————
   8 Royal Canin offers up something of an exception: In both original and

removed cases, an amendment reducing the alleged amount-in-
controversy to below the statutory threshold—like a post-filing develop-
ment that makes recovering the needed amount impossible—will usually
not destroy diversity jurisdiction. See St. Paul Mercury Indemnity Co. v.
Red Cab Co., 

303 U. S. 283, 289, 292

 (1938); Brief for Petitioners 20. But
that rule is inapposite here, by virtue of its subject and function alike.
First, the rule more concerns a fact on the ground—that is, the value of
a suit—than it does the plaintiff ’s selection of claims and parties. So this
Court has viewed it as analogous to the time-of-filing rule applying to
citizenship, which also assesses a factual issue relevant to jurisdiction
only at the suit’s outset. See St. Paul Mercury, 303 U. S., at 294–295;
Rosado v. Wyman, 

397 U. S. 397, 405, n. 6

 (1970); supra, at 12, n. 5. Sec-
ond, the rule responds to the difficulties of assessing a suit’s value and
the likelihood that the calculation will change over the course of litiga-
tion. Especially given that the alleged amount-in-controversy does not
cap damages, “constant litigation” over the matter, having the potential
to alter a court’s jurisdiction, “would be wasteful.” Grupo Dataflux v.
Atlas Global Group, L. P., 

541 U. S. 567

, 580–581 (2004) (making the
same point about changes in citizenship). But as all the examples given
above show, we have never held such a concern to limit the effect of the
                     Cite as: 

604 U. S. ____

 (2025)                   15

                          Opinion of the Court

   The uniformity of that principle, as between original and
removed cases, is not surprising. The appropriateness of
federal jurisdiction—or the lack thereof—does not depend
on whether the plaintiff first filed suit in federal or state
court. Rather, it depends, in either event, on the substance
of the suit—the legal basis of the claims (federal or state?)
and the citizenship of the parties (diverse or not?). (That
focus on substance is indeed why original jurisdiction and
removal jurisdiction generally mirror each other in scope.
See §1441(a).) So in a removed no less than in an original
case, the rule that jurisdiction follows the operative plead-
ing serves a critical function. It too ensures that the case,
as it will actually be litigated, merits a federal forum.
   And with all that recognized, the answer to the disputed
question here becomes yet more certain: On top of §1367, a
panoply of procedural rules shows that a post-removal
amendment excising all federal claims destroys federal ju-
risdiction. Under those rules, the presence of jurisdiction,
in removed as in original cases, hinges on the amended, now
operative pleading. By adding or subtracting claims or par-
ties, and thus reframing the suit, that pleading can alter a
federal court’s authority. And so it is here. When a plain-
tiff, after removal, cuts out all her federal-law claims,
federal-question jurisdiction dissolves. And with any fed-
eral anchor gone, supplemental jurisdiction over the resid-
ual state claims disappears as well. The operative pleading
no longer supports federal jurisdiction, and the federal
court must remand the case to the state court where it
started.
                              C
  Royal Canin contends that this Court has twice before
reached the opposite conclusion—first, in Carnegie-Mellon
Univ. v. Cohill, 

484 U. S. 343

 (1988), and next in Rockwell,
——————
plaintiff ’s decision, as the master of her complaint, to add or subtract
claims or parties.
16      ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                      Opinion of the Court

in a footnote to the analysis we have related above. See
supra, at 8–9, 12. But in each case, the relied-on passage is
extraneous to the Court’s holding and reasoning, and so
cannot bear the weight of Royal Canin’s argument.
   Begin with Cohill, which shares the procedural posture
of this case but asked and answered a different question.
There, as here, the plaintiff filed a suit in state court, as-
serting both federal and state claims; the defendant re-
moved the suit to federal court; and the plaintiff then
dropped her federal claim and sought a remand. The Dis-
trict Court granted that request over the defendant’s objec-
tion. But in opposing that ruling, the defendant did not ar-
gue (à la Royal Canin) that the court should have held on to
the case. Rather, the defendant urged that the court should
have dismissed the case outright instead of remanding it.
(The difference mattered because the statute of limitations
had by then expired, and a dismissal would have ended the
suit.) The disputed issue was thus not about keeping the
case in federal court, but about two different ways of expel-
ling it. Or as Cohill put it: The question “present[ed] is
whether the District Court could relinquish jurisdiction
over the case only by dismissing it without prejudice or
whether the District Court could relinquish jurisdiction
over the case by remanding it to state court as well.” 

484 U. S., at 351

. We held that the federal court could remand
as well as dismiss, even though no statute then authorized
the former action. 

Id., at 357

; see §1447(c) (now filling that
vacuum). Our reasoning, in that pre-§1367 era, focused on
the values served by supplemental jurisdiction, as set out
in Gibbs. “[E]conomy, convenience, fairness, and comity,”
we stated, “support[ ] giving a district court discretion to re-
mand when the exercise of [supplemental] jurisdiction is in-
appropriate.” Cohill, 

484 U. S., at 351

. So when a plaintiff
cuts her federal claims, the court should have a choice about
how best to get rid of the case.
   In one spot, though, the Cohill Court intimated a view on
                 Cite as: 

604 U. S. ____

 (2025)           17

                     Opinion of the Court

whether the District Court also had discretion to retain the
suit. The sentence, pressed by Royal Canin, comes just be-
fore the Court’s statement of the question presented, quoted
above. See Brief for Petitioners 10–11, 19. It reads: “When
the single federal-law claim in the action was eliminated at
an early stage of the litigation, the District Court had a
powerful reason to choose not to continue to exercise juris-
diction.” Cohill, 

484 U. S., at 351

. In using the word
“choose,” Cohill suggested that the court, though having
strong cause to dismiss or remand, likewise had authority
to decide the case.
   But that slender (and somewhat backhanded) dictum
cannot make us stop in our tracks. Nowhere did Cohill an-
alyze why a federal court could retain jurisdiction once an
amendment excised all federal-law claims. Cohill simply
supposed the court could and asserted as much, without
pausing to consider the matter. And that lack of scrutiny
reflected the issue’s lack of importance—not in today’s case
of course, but in that earlier one. As just explained, the
District Court in Cohill never thought to exercise jurisdic-
tion after the amendment; the issue in dispute was only
how to get rid of the action. So Cohill’s view about keeping
jurisdiction was gratuitous, and no sooner noted than
dropped. It supported neither the decision’s result nor its
values-based reasoning. And anyway, our own analysis is
based mainly on legal authorities post-dating Cohill—most
notably, §1367 and our Rockwell decision. See supra, at 6–
10, 12. Those later materials supersede whatever Cohill
presumed about exercising federal jurisdiction in a case like
this one. So by virtue of both what it decided and when it
arose, Cohill does not matter to the question before us.
   That leaves the Rockwell footnote Royal Canin cites. As
earlier explained, the body of Rockwell examines what hap-
pens in an original case when a plaintiff amends a com-
plaint to expunge federal claims. See supra, at 8–9, 12. The
federal court, Rockwell held, loses jurisdiction. See 549
18        ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                           Opinion of the Court

U. S., at 473–474. But in a two-sentence footnote, the Rock-
well Court said that the opposite rule applies in removed
cases. “[W]hen a defendant removes a case to federal court
based on the presence of a federal claim,” the footnote
stated, “an amendment eliminating the original basis for
federal jurisdiction generally does not defeat jurisdiction.”
Id., at 474, n. 6. That is because “removal cases raise
forum-manipulation concerns that simply do not exist when
it is the plaintiff who chooses a federal forum and then
pleads away jurisdiction through amendment.” Ibid. (em-
phasis in original). The footnote thus sets out exactly the
rule Royal Canin wants—and, in so doing, gives the com-
pany its best argument.
   But still, the footnote is dictum, and does not control the
outcome here. Rockwell was an original federal case, not a
removed one. So the footnote’s assertion of a special rule
for removed cases was outside the issue being decided—or
more colloquially put, beside the point. The statement had
no bearing on the Court’s conclusion about jurisdiction in
original cases. Nor did it relate to the rationale supporting
that result. And to top it off, the footnote was itself barely
reasoned. 9 This Court has often stated that “drive-by juris-

——————
  9 The footnote’s cursory reference to “forum-manipulation concerns”

fails on multiple levels. First, and most practically, plaintiffs can usually
forum shop without any resort to amendments. Except when a statute
of limitations has expired, a plaintiff need only voluntarily dismiss her
federal suit and file a new state-claim-only action in state court. So the
forum-manipulation benefit of the Rockwell footnote’s approach to re-
moved federal-question cases is likely quite marginal. Second, that ap-
proach conflicts with the one taken in the most comparable situation:
when in a removed diversity case, a plaintiff seeks a remand to state
court by means of adding a non-diverse party. As noted earlier, the rule
in that context is the standard one: Jurisdiction follows the amended
pleading—regardless of any (probably minor) forum-manipulation con-
cerns. See §1447(e); supra, at 14. Third and most important, those
policy-based concerns, even if significant, cannot trump a federal statute.
And as we elsewhere discuss—including in the next paragraph—§1367
                      Cite as: 

604 U. S. ____

 (2025)                      19

                           Opinion of the Court

dictional rulings”—asserting or denying jurisdiction “with-
out elaboration,” or analysis of whether anything “turn[ed]
on” the ruling—should be accorded “no precedential effect.”
Wilkins v. United States, 

598 U. S. 152, 160

 (2023) (quoting
Arbaugh v. Y & H Corp., 

546 U. S. 500, 511, 512

 (2006);
alteration in original; Henderson v. Shinseki, 

562 U. S. 428, 437

 (2011)). The admonition goes double for throwaway
footnotes about jurisdictional issues neither raised in nor
conceivably relevant to a case. We therefore need not follow
the Rockwell footnote just because it exists; our adherence
instead depends on whether it withstands analysis. 10
   And it does not, for all the reasons already given. A recap
here fittingly begins with Rockwell’s own core insight,
which points the opposite way. Federal courts, Rockwell
stated, “look to the amended complaint to determine juris-
diction.” 

549 U. S., at 474

. That rule, as earlier described,
explains a host of jurisdictional outcomes. See supra, at 11–
14. It operates in federal-question cases and diversity
cases, both to destroy and to create jurisdiction. And it can-
not give way, in a case like this one, just because the case
was removed from state to federal court. When, as here, a
complaint asserts both federal and state claims, and an
amendment strips out the federal ones, a district court’s ju-
risdiction depends on §1367. And §1367, as earlier shown,
makes no distinction between cases beginning in federal
court and cases removed there. See supra, at 8–9. If in the
former the amendment “defeat[s] jurisdiction,” as Rockwell
rightly held, 

549 U. S., at 473

, then so too in the latter. Re-
gardless of removal, the plaintiff ’s excision of her federal-
——————
offers no basis for treating original and removed cases differently, as the
Rockwell footnote proposes. See supra, at 8–9.
  10 It is of course a much different thing for this Court to reach that

conclusion than for a lower court to do so. We do not at all fault any court
that relied on the Rockwell footnote to find jurisdiction in a case like this
one. Courts that did so simply took us at our word, in a way both under-
standable and appropriate.
20      ROYAL CANIN U. S. A., INC. v. WULLSCHLEGER

                      Opinion of the Court

law claims deprives the district court of its authority to de-
cide the state-law claims remaining.
                             III
  For those reasons, the District Court here should have
remanded Wullschleger’s suit to state court. The earliest
version of that suit contained federal-law claims and there-
fore was properly removed to federal court. The additional
state-law claims were sufficiently related to the federal
ones to come within that court’s supplemental jurisdiction.
But when Wullschleger amended her complaint, the juris-
dictional analysis also changed. Her deletion of all federal
claims deprived the District Court of federal-question juris-
diction. And once that was gone, the court’s supplemental
jurisdiction over the state claims dissolved too. Wull-
schleger had reconfigured her suit to make it only about
state law. And so the suit became one for a state court.
  We accordingly affirm the judgment of the Court of Ap-
peals for the Eighth Circuit.

                                             It is so ordered.