                                        PRECEDENTIAL
             UNITED STATES COURT OF APPEALS
                  FOR THE THIRD CIRCUIT
                       _____________

                           No. 18-1831
                          _____________

                  T MOBILE NORTHEAST LLC,
                                Appellant

                                 v.

         CITY OF WILMINGTON, DELAWARE;
CITY OF WILMINGTON ZONING BOARD OF ADJUSTMENT
                   _____________

           On Appeal from the United States District Court
                     for the District of Delaware
                      (D.C. No. 1-16-cv-01108)
             District Judge: Hon. Eduardo C. Robreno
                          _______________

                             Argued
                        September 12, 2018

Before: JORDAN, NYGAARD, and VANASKIE, * Circuit Judge
                (Filed: January 10, 2019)


       *
         The Honorable Thomas I. Vanaskie retired from the
Court on January 1, 2019 after the argument and conference
in this case, but before the filing of the opinion. This opinion
is filed by a quorum of the panel pursuant to 28 U.S.C.
§ 46(d) and Third Circuit I.O.P. Chapter 12.
                        _______________

Thomas S. Thompson [ARGUED]
Davis Wright Tremaine
1919 Pennsylvania Avenue, NW
Ste. 800
Washington, DC 20006

Counsel for Appellant

Joseph Van Eaton [ARGUED]
Best Best & Krieger
2000 Pennsylvania Avenue
Ste. 5300
Washington, DC 20006

Counsel for Appellees
                        _______________

                  OPINION OF THE COURT
                      _______________


JORDAN, Circuit Judge.

      No one likes bad cell phone reception or slow
streaming data on their smartphone, but that does not mean
anyone wants a cellular antenna in their neighborhood, which
is why there are zoning battles like the one central to this
case.

      T Mobile Northeast LLC (“T Mobile”), a wireless
telecommunications service provider, applied to the Zoning
Board of Adjustment (“ZBA”) of the City of Wilmington,
Delaware for permission to erect an antenna in the City. The




                              2
ZBA said no. So, relying on a provision of federal law that
allows a disappointed wireless service provider like T Mobile
to seek review in a district court “within 30 days after” a
zoning     authority’s     “final     action,”   47    U.S.C.
§ 332(c)(7)(B)(v), T Mobile filed suit. After the case had
proceeded for over a year, however, the District Court
concluded that it lacked jurisdiction. The Court reasoned that
because T Mobile filed its complaint before the ZBA released
a written decision confirming an earlier oral rejection of the
zoning application, the claim was not ripe. And, since
T Mobile did not supplement its complaint to include the
ZBA’s written decision within 30 days of its issuance, the
Court also concluded that relation back could not remedy the
ripeness defect. The District Court thus granted the City’s
motion for summary judgment.

       T Mobile now appeals. It argues that its complaint
was not premature or, in the alternative, that its supplemental
pleading cured any ripeness problem. We agree that the grant
of summary judgment was improper and, for the reasons that
follow, will remand the case for further proceedings
consistent with this opinion.

I.    BACKGROUND

      A.     Statutory Framework

       This dispute is governed by the Telecommunications
Act of 1996 (“TCA”), which amended the Federal
Communications Act of 1934 and includes provisions on
mobile phone services. Pub. L. No. 104-104, §§ 1, 704, 110
Stat. 56, 56, 151 (1996); 47 U.S.C. § 332. Passed to
“encourage the rapid deployment of new telecommunications




                              3
technologies,” Preamble, 110 Stat. at 56, the TCA provides
for expedited review in federal court of a denial of permission
to build a cell phone antenna, id. § 704, 110 Stat. at 151-52.
Such review is a “benefit Congress expressly intended to
confer on wireless providers[.]” Nextel W. Corp. v. Unity
Twp., 282 F.3d 257, 264 (3d Cir. 2002). At the same time,
the TCA also serves to preserve local zoning authority. 47
U.S.C. § 332(c)(7).

        At issue here are three key sections of the statute.
First, the TCA mandates that “[a] State or local government
or instrumentality thereof shall act on any request for
authorization to place, construct, or modify personal wireless
service facilities within a reasonable period of time after the
request is duly filed[.]” Id. § 332(c)(7)(B)(ii). The Federal
Communications Commission (“FCC”) has interpreted
“reasonable period of time” in that statutory provision to
mean that zoning authorities have a “shot clock” 1 and must
act within 90 days of an application to attach an antenna to an
existing structure or 150 days of an application where a new
support structure is to be built. Petition for Declaratory

       1
          “Shot clock” is a term borrowed from basketball. In
that game, it signifies a time limit to make a shot attempt,
beginning once a team has possession of the basketball. See,
e.g., Nat’s Basketball Ass’n, NBA Rulebook Rule No. 7: Shot
Clock (2018-2019), http://official.nba.com/rule-no-7-24-
second-clock/. If the team has not made a shot attempt, i.e.,
acted, within the prescribed time limit, it forfeits possession
of the ball. Id. Here, the permitting authority has exclusive
jurisdiction over an application until it fails to act within a
“reasonable period of time.” 47 U.S.C. §§ 332(c)(7)(A),
332(c)(7)(B)(ii).




                              4
Ruling to Clarify Provisions of Section 332(c)(7)(B), 24 FCC
Rcd. 13994, 14008, 14012 (2009). Second, in what we will
call the “review provision” of the statute, the TCA grants
“[a]ny person adversely affected by any final action or failure
to act by a State or local government or any instrumentality
thereof” a right to have that locality’s decision reviewed by
“commenc[ing] an action” “within 30 days” in district court.
47 U.S.C. § 332(c)(7)(B)(v). Third, in the statute’s “denial
provision,” the TCA states that “[a]ny decision by a State or
local government or instrumentality thereof to deny a request
to place, construct, or modify personal wireless service
facilities shall be in writing and supported by substantial
evidence contained in a written record.”                    Id.
§ 332(c)(7)(B)(iii). Notably, the terms “act,” “final action,”
and “decision … to deny” are not defined in the TCA.
Furthermore, the statute does not make clear whether “final
action” should be read to encompass all decisions to deny,
including oral ones, nor does it address whether there is a
difference between an “act” for purposes of the shot clock
and a “final action” for purposes of judicial review.

      B.     Factual Background

       T Mobile is a telecommunications service provider. It
says that it needs to erect a cellular antenna to fill “a
significant gap” in coverage for its customers in Wilmington,
Delaware, (Opening Br. at 3) presumably where there has
been an increase in phone calls and data usage. T Mobile
wants to put its antenna on top of a senior living high-rise in
the City, but, because a special exception to local zoning laws
is needed, it first had to go to the ZBA. It filed an initial
application and then, on August 25, 2016, a final amended
application, seeking the exception.




                              5
       The ZBA held a hearing on October 26, 2016, to
consider T Mobile’s request, some two months after the final
amended application was submitted. During the hearing,
T Mobile presented evidence of the need for the antenna and
discussed proposals to address aesthetic concerns. The ZBA
also received objections from members of the local
community, some of whom were outspoken in worrying
about the effects of radio frequency emissions. At the end of
the hearing, the ZBA denied T Mobile’s application in a
unanimous oral decision.

       The Board gave several reasons for the denial. One
board member said the ZBA should not encourage the use of
a senior living community rooftop as the base for an antenna
because of the potential adverse effect on the properties in the
neighborhood. Another board member said there was not
enough proof of a need for additional coverage to support the
application. The Chairman said there was not enough
evidence that T Mobile needed the antenna and that it did not
appear to satisfy the zoning code in terms of placement and
height restrictions.

       The ZBA’s oral decision to deny the application was
not put in writing on October 26 or anytime soon thereafter.
According to T Mobile, that fits a “pattern and practice of
[the ZBA] not issuing a written decision of land use denials
unless or until the City is sued.” (Opening Br. at 7.) Only
after T Mobile had filed its initial complaint in the District
Court, and after the City filed its answer, did the ZBA issue
its written decision and explanation of its reasoning for
denying the application.




                               6
        T Mobile asserts that the denial of its application
violates the TCA. Under the statute, such a denial is invalid
if it has the “effect of prohibiting the provision of personal
wireless services[,]” 47 U.S.C. § 332(c)(7)(B)(i)(II), or is “on
the basis of the environmental effects of radio frequency
emissions[,]” id. at § 332(c)(7)(B)(iv). T Mobile claims that
Wilmington’s denial was improper on both of those grounds. 2
But those assertions go to the merits and are not actually
before us on this appeal. At issue now is whether T Mobile’s
claim can be heard at all.

       C.     Procedural History

        Evidently with its eye on the 30-day deadline in the
TCA’s review provision, T Mobile filed a lawsuit in the
United States District Court for the District of Delaware
within 30 days of the ZBA’s oral decision, challenging that
denial. 3 In addition to its claims on the merits, T Mobile’s
initial complaint alleged that the City violated procedures
mandated in the TCA, specifically those in the denial
provision, by failing to provide a written decision

       2
          T Mobile also raised a Delaware state law claim.
That claim is not at issue here and does not impact
T Mobile’s claims under federal law.
       3
           For reasons discussed herein, the 30-day filing
deadline was not triggered by the oral decision. See infra pp.
12-20. If it were, however, T Mobile’s complaint would have
been timely. The oral decision was delivered at the
October 26, 2016 hearing. Suit was filed on November 28,
2016, but because the thirtieth day from October 26 fell on a
weekend, the November 28 filing was within the 30-day
window. Fed. R. Civ. P. 6(a)(1).




                               7
contemporaneous with its oral decision and by not supporting
the denial with substantial evidence.

        The parties entered into a stipulation asking the
District Court for an expedited case schedule, as provided for
in the review provision of the TCA.                47 U.S.C.
§ 332(c)(7)(B)(v). That request was granted. Wilmington
then answered the complaint, asserting a number of
affirmative defenses, including that the complaint was not
ripe because the ZBA had not yet issued a final written
decision. Nevertheless, the City did not, at that time, file a
motion to dismiss for failure to state a claim or for lack of
jurisdiction. Two days after the City filed its answer, the
ZBA issued a written decision on T Mobile’s application.
The parties pressed forward with the suit and prepared a
discovery plan, which specifically mentioned the written
decision. T Mobile filed a motion for summary judgment,
which the City met with a cross-motion for summary
judgment. The City’s motion was styled in the alternative as
a motion to dismiss the complaint as unripe because it was
filed prematurely, i.e., before the written decision had been
issued.

       Not until December 21, 2017, nearly a year after the
ZBA issued its written denial, did T Mobile file a motion
seeking leave to amend or supplement the initial complaint to
note the issuance of that written decision. 4 The District Court

       4
         When “[a] claim or defense set out in a pleading [is]
affected by events that occur after the pleading is filed ….
Rule 15(d) allows a court,” to permit a supplemental
pleading. 3 James Wm. Moore et al., Moore’s Federal
Practice ¶ 15.30 (3d ed. 2018). Supplemental pleadings




                               8
granted the motion to supplement.            Wilmington then
responded by moving to dismiss the supplemental complaint
as untimely because it failed to cure the defect.

        Ultimately, the District Court granted Wilmington’s
cross-motion for summary judgment for want of jurisdiction,
without ruling on the City’s motion to dismiss. The Court
first concluded that the initial complaint was irreparably
unripe because both the TCA and Delaware law require the
ZBA to issue a written decision before the agency’s action
could be considered final, and T Mobile had thus filed its
initial complaint too soon. Second, the Court said that the
supplemental complaint could not fix the ripeness problem
because it was filed past the 30-day window for seeking
review of the ZBA’s final action. Because the Court reached



under Rule 15(d) differ from amended pleadings made under
Rule 15(a). First, amended pleadings “relate to matters that
occurred prior to the filing of the original pleading and
entirely replace the earlier pleading; [supplemental pleadings]
deal with events subsequent to the pleading to be altered and
represent additions to or continuations of the earlier
pleadings.” 6A Charles Alan Wright et al., Federal Practice
& Procedure § 1504 (3d ed. 2018). Second “certain
amendments may be made as a matter of course within stated
time periods, whereas all supplemental pleadings require
leave of court under Rule 15(d).” Id. “Parties and courts
occasionally confuse supplemental pleadings with amended
pleadings and mislabeling is common.” Id. Here, T Mobile’s
complaint was filed as an amended complaint but it is
properly categorized as a supplemental complaint, and we
will refer to it as such herein.




                              9
that determination, it found it unnecessary to conclude
whether T Mobile’s supplemental complaint was entitled to
the benefit of the relation-back doctrine under Rule 15(c).

       This appeal followed.
II.    DISCUSSION 5

        T Mobile challenges the District Court’s grant of
summary judgment in favor of Wilmington, contending that
there is jurisdiction to hear its case. It advances two
alternative grounds for reversal: that its complaint was ripe
because the ZBA’s oral decision qualifies as a “final action”
under the review provision of the TCA, and, in the
alternative, that the supplemental complaint relates back to
and cures any ripeness problem with its initial complaint.
Those arguments in turn raise three questions for determining
whether the District Court’s jurisdictional ruling was proper.
First, whether the oral decision of the ZBA was a final action.
Second, whether the timing requirement in the TCA’s review
provision is jurisdictional. And third, whether an untimely

       5
           The District Court had jurisdiction to consider its
jurisdiction under 28 U.S.C. §§ 1331 and 1367(a), but
determined the complaint contained incurable jurisdictional
defects and declined to reach the merits. We have jurisdiction
pursuant to 28 U.S.C. § 1291. We review all the issues
presented in this case de novo, as they involve only legal
issues, i.e., interpretation of a federal statute and of a Federal
Rule of Civil Procedure. Giles v. Campbell, 698 F.3d 153,
155 (3d Cir. 2012); Viera v. Life Ins. Co. of N. Am., 642 F.3d
407, 413 (3d Cir. 2011); DIRECTV Inc. v. Seijas, 508 F.3d
123, 125 (3d Cir. 2007).




                               10
supplemental complaint can relate back and cure an unripe
initial complaint. Although we disagree with T Mobile that
an oral decision of the ZBA qualifies as a “final action,” we
agree that jurisdiction was proper in the District Court
because the timing requirement in the TCA’s review
provision is non-jurisdictional, and T Mobile’s supplemental
complaint therefore relates back and cures the ripeness
problem with the initial complaint. The District Court should
thus have reached the merits of the dispute.

       A.     The Oral Decision Was Not a Final Action of
              the ZBA.

       The ripeness of T Mobile’s initial complaint depends
upon whether the ZBA’s oral decision was a “final action”
within the meaning of the TCA. Consideration of that issue
uncovers another: whether the TCA requires a locality to
render its decision in writing for that decision to qualify as a
final action. The District Court held that, under both federal
and Delaware law, only a written decision can serve as a final
action of the ZBA. Because traditional hallmarks of agency
action and the statutory text and structure of the TCA favor
that approach, we agree that only a written decision can serve
as a locality’s final action when denying an application.

        In Delaware Riverkeeper Network v. Secretary
Pennsylvania Department of Environmental Protection,
(Riverkeeper III), we determined that, when reviewing
finality under the Natural Gas Act, “[a]lthough the
decisionmaking process we are reviewing is defined by [state]
law, we nevertheless apply a federal finality standard to
determine whether Congress has made the results of that
process reviewable[.]” 903 F.3d 65, 72 (3d Cir. 2018). The




                              11
same reasoning holds true here, since, for the TCA just as for
the Natural Gas Act, “the finality requirement itself, along
with the presumption that Congress intended us to apply it,
are creatures of federal, not state, law.” Id. at 71.

        Under federal law, not all agency determinations are
final actions. Bacon v. Sullivan, 969 F.2d 1517, 1519 (3d Cir.
1992).     Final agency actions bear certain “traditional
hallmarks” that demonstrate “[t]here is nothing left for the
agency to do[,]” Del. Riverkeeper Network v. Sec’y of Pa.
Dep’t of Envtl. Prot., (Riverkeeper II), 870 F.3d 171, 178 (3d
Cir. 2017). We noted those hallmarks on an earlier occasion
when we said that, “[f]inal agency action must mark the
consummation of the agency’s decisionmaking process, must
not be of a merely tentative or interlocutory nature, and must
be one by which rights or obligations have been determined,
or from which legal consequences will flow.” Riverkeeper
III, 903 F.3d at 72, 75 (citation and internal quotation marks
omitted).

       To decide what the TCA requires for finality, we
begin, of course, with the text. See, e.g., Ross v. Blake, 136 S.
Ct. 1850, 1856 (2016) (“Statutory interpretation … begins
with the text[.]”) Here, the statutory text makes it clear that,
if a denial is not in writing, there is something left for the
agency to do. The denial provision of the TCA states that
“[a]ny decision … to deny … shall be in writing and
supported by substantial evidence contained in a written
record.” 47 U.S.C. § 332(c)(7)(B)(iii). We see no reason
why the same should not be true for actions besides denial, 6

       6
        For instance, it is not apparent why community
members aggrieved by a decision to grant some permit to a




                               12
but we need not decide that today. It is enough to say that, in
those zoning decisions governed by the TCA, a locality’s oral
declaration of a denial is “of a merely tentative or
interlocutory nature.” Riverkeeper III, 903 F.3d at 72
(citation omitted) (speaking in reference to the Natural Gas
Act); cf. Athens Cellular, Inc. v. Oconee Cty., 886 F.3d 1094,
1104-05, 1107 (11th Cir. 2018) (noting that a zoning board
could have approved the minutes, revised them, or rejected
them, and thus until the board approved the minutes its
decision was not final).

       Moreover, an oral decision is not an action from which
legal consequences flow. Federal law governs finality, but
Delaware’s procedures still matter, and the Delaware
Superior Court has concluded that a written document must
be filed for a ZBA action to be final. McDonald’s Corp. v.
Zoning Bd. of Adjustment for the City of Wilmington, No.
CIV. A. 01A-05-011CG, 2002 WL 88944, at *1 (Del. Super.
Ct. Jan. 10, 2002). The court reasoned that Section 328 of
Title 22 of the Delaware Code, the section that governs
appeals from ZBA proceedings, requires a written document
to be filed because the statute “provides that [s]uch petition
shall be presented to the Court within 30 days after the filing
of the decision in the office of the board.” Id. (internal
quotation marks omitted). That reasoning is persuasive and




wireless provider, assuming those members have standing to
sue, would not be equally entitled to a zoning authority’s
written decision before the time limit in the TCA’s review
provision is triggered.




                              13
shows that, under Delaware law, the ZBA’s oral decision is
without legal consequences. 7

       There are distinct policy advantages to forestalling
judicial scrutiny until a written denial is issued. Requiring a
written decision focuses review on a particular, documented
statement of reasons. See USCOC of Greater Mo. v. City of
Ferguson, 583 F.3d 1035, 1042 (8th Cir. 2009) (“Because the
written decision is the central object of our scrutiny under the
TCA, the process of judicial review is best served by delaying
the ripening of a TCA claim until the local authority has
issued its written decision.”). It also prevents ambiguity with
respect to when a claim can be brought. As the District Court
here stated, to hold otherwise “would promote a pernicious
ambiguity as to when that short period of time begins to run.”
(App. at 7.) And it promotes uniformity of federal procedures
by clarifying when, across all jurisdictions, an action becomes
final.

       7
         T Mobile cites to a different opinion, Schmalhofer v.
Board of Adjustment of Newark, to advance a contrary
position. No. C.A. 99A-05-010-WTQ, 2000 WL 703510
(Del. Super. Ct. May 9, 2000). Schmalhofer states in a
footnote that “a written decision is not required or expressly
contemplated by this section.” Id. at *3 n.3. But T Mobile is
stretching the Schmalhofer court’s language too far. In that
case, the City of Newark had issued a verbatim transcript of
the hearing, so there was a writing. Id. at *3; see infra note
11. There is no indication of any written decision in this case,
prior to December 22, 2016, when the City issued the written
denial bearing the date of December 21, 2016.




                              14
        The Supreme Court’s decision in T-Mobile South, LLC
v. City of Roswell, Georgia, also adds support to the
conclusion that only a written denial can constitute final
action, triggering a party’s right to review. 135 S. Ct. 808
(2015). In that case, the Court held that the “substantial
evidence” supporting a locality’s decision to deny must be
released contemporaneously with the written decision to
deny. 8 Id. at 811-12. In doing so, the Court tied together a
local zoning authority’s final action, which triggers judicial
review, and its decision to deny, which must be in writing.
Indeed, the Supreme Court said in no uncertain terms that,
“[t]he relevant ‘final action’ [in that case, was] the issuance of
the written notice of denial[.]” Id. at 817 n.4. The Court
linked the locality’s decision to deny to the 30-day time limit
to file a complaint after a final action has been taken. Id. at
817 (“Only once the denial is issued would the 30-day
commencement-of-suit clock begin.”); id. at 813 (“[N]ow 29
days after the City denied petitioner’s application—petitioner
filed suit in Federal District Court.”).

        The Court went on to discuss timing, saying, “the
locality must provide or make available its written reasons at
essentially the same time as it communicates its denial[,]”
“[b]ecause an entity may not be able to make a considered

       8
           The Court was interpreting the denial provision,
which, as we noted earlier, states that, “[a]ny decision by a
State or local government or instrumentality thereof to deny a
request to place, construct, or modify personal wireless
service facilities shall be in writing and supported by
substantial evidence contained in a written record.” 47
U.S.C. § 332(c)(7)(B)(iii), City of Roswell, 135 S. Ct. at 811.




                               15
decision whether to seek judicial review without knowing the
reasons for the denial of its application, and because a court
cannot review the denial without knowing the locality’s
reasons[.]” Id. at 816. The majority opinion was critical of
the dissent for attempting to “fashion a world in which a
locality can wait until a lawsuit is commenced and a court
orders it to state its reasons[,] … [leaving the challenging
entity to] risk being sandbagged by the written reasons that
the locality subsequently provides in litigation after the
challenging entity has shown its cards.” Id. at 816 n.3. That
critique is premised on the written decision being the final
action that starts the 30-day time limit for commencing suit. 9

       The Supreme Court anticipated that localities might
need to delay issuing a written denial if they are not ready to
release their substantial reasons. See id. at 817 (noting that

       9
          T Mobile asserts that Wilmington has a “pattern and
practice of not issuing a written decision of land use denials
unless or until the City is sued.” (Opening Br. at 7.) But if
only a written denial is a final action, the shot clock requires
the City to issue that written decision within a given time
period. 24 FCC Rcd. 13994, 14012 (2009). T Mobile also
asserts that when a locality has a pattern and practice of not
releasing written decisions, that practice delays the overall
process, since a cellular service provider would be required to
initiate two causes of action: one to compel a written decision
and another to challenge that written decision. That,
however, is precisely what Congress envisioned by providing
separate remedies for a failure to “act” within a reasonable
time period and for an improper denial.              47 U.S.C.
§ 332(c)(7)(B)(iii).




                              16
“[i]f a locality is not in a position to provide its reasons
promptly, the locality can delay the issuance of its denial
within this 90– or 150–day window, and instead release it
along with its reasons once those reasons are ready to be
provided.”). That further counsels against treating an oral
determination as a final action since, if an oral determination
is deemed a final action, localities will be unable to take
advantage of the permissible delay afforded by the shot clock
for publishing their reasoning.

       Two of our sister courts of appeals agree that only a
written decision can constitute final action. The Eighth
Circuit in USCOC of Greater Missouri v. City of Ferguson
stated that “[t]he plain language of the TCA indicates that
‘final action’ does not occur until issuance of a written
decision.” 583 F.3d at 1041. The Eleventh Circuit in
Preferred Sites LLC v. Troup County likewise held a
complaint to be timely when it was filed within 30 days of a
written decision, even though it was filed more than 30 days
after an oral decision. 10 296 F.3d 1210, 1217-18 (11th Cir.

       10
          T Mobile attempts to distinguish Preferred Sites by
stating that, unlike here, the case did “not address a city that
does not issue a written decision close in time to when it
makes the decision to deny.” (Opening Br. at 37.) But that
argument is irrelevant to whether the statutory text requires a
writing for an agency decision to be final. T Mobile also cites
to Preferred Sites to argue that it should not matter if there is
a writing requirement since the oral denial could be seen as
akin to a court announcing a decision. It explains that “when
an appeal is filed after the court announces a decision, but
before the entry of the judgment, it is treated as being filed on
the date of entry.” (Opening Br. at 28-29 (citing Preferred




                               17
2002) (concluding that, “[b]ased on the plain language of the
statute,” that “a ‘final action’ occurs when the state or local
authority issues its written decision. The statute expressly
mandates a … decision … committed to writing. Until the
state or local authority issues its written notification, its task
under the statute is not complete.”). No circuit has held
otherwise.

        Persuasive authority thus indicates that any action, and
certainly a denial, must be in writing to be final. But, there is
another possible interpretation of the statutory text. The
words “shall be in writing” could be read not as a condition of
finality, but instead as a simple directive to state and local
governments to place their final action in writing. “The TCA
provides no express answer to … when a local government’s
permitting decision becomes a ‘final action,’ which starts the
thirty-day clock.” Athens Cellular, 886 F.3d at 1102-03. The
statute only states that denials must be in writing. 47 U.S.C.
§ 332(c)(7)(b)(iii). Decisions to grant are not limited in the
same way. Id. And, Congress used the words “decision to
deny” in one statutory subsection and “final action” in
another, which could evince an intent to give those terms
different meanings. As the Supreme Court has “recognized
… Congress’s use of certain language in one part of the
statute and different language in another can indicate that
different meanings were intended.” Sebelius v. Auburn Reg’l
Med. Ctr., 568 U.S. 145, 156 (2013) (citation and quotation



Sites, 296 F.3d at 1217 n.7).) That analogy did appear in
Preferred Sites, but it was only contained in a footnote. No
other court has followed that line of reasoning, and we
decline to follow it here.




                               18
marks omitted). Thus, it could be argued, if Congress wanted
to mandate a writing for zoning denials to constitute final
action, it could have been more explicit, providing, for
instance, that a “decision must be in writing to qualify as a
final action.”

       But, of course, one can almost always fault legislative
drafting, like other kinds of writing, after the fact. That
something might have been said even more clearly does not
mean it is not clear enough. So, “[r]ather than expecting (let
alone demanding) perfection in drafting,” we can “construe[]
statutes to have a particular meaning even as we
acknowledge[] that Congress could have expressed itself
more clearly.” Torres v. Lynch, 136 S. Ct. 1619, 1633
(2016).

       The text and structure of the statute, Delaware
procedures, Supreme Court reasoning, our sister circuits’
decisions, and policy arguments all support the conclusion
that a writing is in fact a requirement for a denial to be final. 11
In light of that conclusion, the ZBA’s oral determination on

       11
           What constitutes a “writing” has some flexibility,
though. See, e.g., Omnipoint Holdings, Inc. v. City of
Southfield, 355 F.3d 601, 605-07 (6th Cir. 2004) (approving
minutes by written resolution was a final action that bound
the parties). In City of Roswell, for example, the Supreme
Court indicated that minutes of an oral meeting could be
sufficient. 135 S. Ct. at 816. Here, however, there is no
evidence that the ZBA’s oral determination was noted in the
minutes of the October 26th meeting and issued by the City as
its formal decision.




                                19
October 26, 2016, was not a final action ripe for judicial
review. Therefore, as that oral determination was not reduced
to writing until December 22, 2016, preceding the filing of
T Mobile’s initial complaint, that complaint’s cause of action
was not ripe.




                             20
       B.     No Separate Time Limit Exists Following an
              Oral Determination.

       As an alternative to its argument that the ZBA’s oral
decision was a final action, T Mobile asks us to consider
whether a “local government must issue the ‘writing’ close in
time to the ‘decision … to deny’ to establish a ‘final action’
that will be subject to expedited review.” 12 (Opening Br. at
41.) Essentially, T Mobile is asserting that the “shot clock”
governing the time to act, which allows a wireless carrier to
sue for a locality’s failure to act, is insufficient, and that a
new requirement, albeit not in the statute, should be imposed
on localities. Under T Mobile’s proposed rule, an oral
decision would have to be reduced to writing within a
specified time period. That argument assumes that an oral
determination can serve to satisfy the requirement to “act” on
a request within the limits of the shot clock, and that, without
a separate judicially created time limit, there would be no
deadline for the locality to release its written decision to deny,
despite City of Rowell’s contemporaneous writing
requirement. Because we conclude that a denial must be in
writing to be a final action, the issuance of that writing is the
government “act” ruled by the shot clock. 13 Aside from the

       12
          Wilmington argues that T Mobile has waived that
issue, but we need not address that argument because we
conclude that no such requirement exists.
       13
          Again, the Supreme Court held in City of Roswell
that a locality’s decision to deny must be accompanied by
substantial reasons. 135 S. Ct. at 811-12. Otherwise, if a
locality were able to withhold its reasoning for its decision,
those aggrieved by the locality’s actions would “be left to




                               21
time limits associated with the “shot clock,” there is no other
deadline governing the issuance of a written decision
following an oral determination. 47 U.S.C. § 332(c)(7)(b).
Any time limit we fabricated would be inappropriate.

        T Mobile argues that, without a requirement for
localities to issue a written decision within a set amount of
time following an oral determination, wireless carriers are left
“to wait until the FCC ‘shot clock’ expires – which could be
90 or 150 days depending on the type of installation involved
– and then [to] file an action alleging that the City has failed
to act in a reasonable time[.]” (Opening Br. at 45.) It also
contends that a “failure to act” lawsuit is insufficient because
the remedy for a successful suit is simply an order telling the
City to issue a written decision. In T Mobile’s view, forcing
wireless providers to sue both to compel a written decision
once the shot clock is violated and again to contest the written
decision serves only to “create yet further delay.” (Opening
Br. at 46.)




guess at what the locality’s written reasons will be, write a
complaint that contains those hypotheses, and risk being
sandbagged by the written reasons that the locality
subsequently provides in litigation after the challenging entity
has shown its cards.” Id. at 816 n.3. If an applicant cannot
file suit, however, because the locality’s “final action” has not
yet occurred, those concerns vanish. The ZBA’s decision
here, when reduced to writing, was both its decision to deny
and its final action.




                               22
       Those concerns are overstated and, in any case,
irrelevant. The shot clock begins to run once a wireless
provider files its application, so it is already ticking before
any oral decision is made. If the locality fails to meet that
deadline by not issuing a written decision before the shot
clock expires, the wireless provider can bring a claim for a
“failure to act.” 14 24 FCC Rcd. 13994, 14012 (2009). T
Mobile asserts that requiring a separate failure-to-act suit, in
addition to a suit on the merits, undercuts the statutory
purpose of expedited judicial review, particularly in cases
where the locality has a “pattern and practice of not issuing a
written decision of land use denials unless or until [it] is
sued.” (Opening Br. at 7.) But the statute’s own remedies
cannot possibly undercut its purpose. A separate failure-to-
act claim is the very remedy Congress chose for shot clock
violations. 24 FCC Rcd. 14013 at ¶ 4 (2009). Whether or not
T Mobile likes that policy choice, it is the one Congress
made, and we are not free to change it.

       C.     The Timing Requirement Is Not
              Jurisdictional.

       Because we hold that a writing is required for a denial
to constitute a final action, T Mobile’s initial complaint was
not ripe for review when filed.              And, T Mobile’s
supplemental complaint was filed more than 30 days after the
ZBA issued its written decision and was therefore untimely
under the TCA’s review provision.                  47 U.S.C.
§ 332(c)(7)(B)(v).     Thus, the District Court only had
jurisdiction if T Mobile’s supplemental complaint cured the

       14
          It is not clear which time limit would have applied in
this case and whether it would have been violated.




                              23
ripeness flaw in its initial complaint by relating back to the
original filing date. If the 30-day time limit in the TCA’s
review provision is nonjurisdictional, we can safely say that
relation back is possible and allows a supplemental complaint
to cure a defective premature filing. 15 At the outset, then, we
must determine whether that 30-day time limit is
jurisdictional, being mindful both of the Supreme Court’s
counsel to exercise caution before holding timing
requirements to be jurisdictional and of its guidance regarding
what constitutes a jurisdictional limit. 16 Sebelius, 568 U.S. at
149, 153-54. Caution is indeed warranted because statutes of
limitations and other filing deadlines “ordinarily are not
jurisdictional.” Id. at 154; see also United States v. Kwai Fun
Wong, 135 S. Ct. 1625, 1632 (2015) (“[M]ost time bars are
nonjurisdictional.”).


       15
         We do not reach the issue of whether an unripe
complaint can be cured by a supplemental or amended
pleading over which the Court lacked jurisdiction.
       16
          The City claims that our decision in Nextel Partners
Inc. v. Kingston Township, 286 F.3d 687 (3d Cir. 2002) is
effectively determinative. Not so. In Kingston Township,
then-Judge Alito noted that the District Court had held the
timing requirement in the TCA’s review provision was
jurisdictional. Id. at 695. But we did not address whether
that determination was correct, nor did we rely on it. Instead,
we concluded that there could be no “failure to act” towards
an application that was not submitted. Id. at 692. Since our
decision in that case, the Supreme Court has clarified the
process for determining if a time limit is jurisdictional.
Sebelius, 568 U.S. at 149.




                               24
        “[T]o ward off profligate use of the term ‘jurisdiction,’
[the Supreme Court has] adopted a readily administrable
bright line for determining whether to classify a statutory
limitation as jurisdictional.” Sebelius, 568 U.S. at 153 (citing
Arbaugh v. Y & H Corp., 546 U.S. 500, 516 (2006))
(quotation marks omitted). We are to ask “whether Congress
has clearly state[d] that the rule is jurisdictional; absent such a
clear statement, we … should treat the restriction as
nonjurisdictional in character.” Id. (alteration in original)
(citation and quotation marks omitted); see also Musacchio v.
United States, 136 S. Ct. 709, 716 (2016) (Thus, “[w]e treat a
time bar as jurisdictional only if Congress has ‘clearly stated’
that it is.”). In deciding whether Congress has made such a
clear statement, “we evaluate the ‘text, context, and relevant
historical treatment.’” United States v. Kalb, 891 F.3d 455,
460 (2018) (quoting Reed Elsevier, 559 U.S. 154, 166
(2010)).

       Referencing that last test, Wilmington asserts that
“[s]ection 332’s statutory grant of jurisdiction to district
courts, the text of the statute, the placement of the filing
window in that same section, and the well-established
treatment of the filing window as jurisdictional, [all
demonstrate] that the filing window is jurisdictional.”
(Answering Br. at 15.) We disagree. The differences
between the review provision’s timing requirement and the
timing requirement we held to be jurisdictional in Kalb, and
the similarities between the review provision’s timing
requirements and those at issue in Sebelius and Musacchio,
which the Supreme Court held to be nonjurisdictional,
actually support treating the timing requirement in the TCA’s
review provision as nonjurisdictional.




                                25
        First, although Wilmington says that the text of the
statute indicates Congress’s desire to make the 30-day timing
requirement jurisdictional, the text does not use the term
“jurisdictional” or any variation of it to describe the timing
requirement. 47 U.S.C. § 332(c)(7)(B)(v). To the contrary,
the statute uses permissive rather than mandatory language.
Unlike the timing requirement we held to be jurisdictional in
Kalb, which mandated that an action would be barred if not
filed in time, the TCA’s review provision states that an action
“may” be filed within 30-days. Compare Kalb, 891 F.3d at
460 with 47 U.S.C. § 332(c)(7)(B)(v). The language is much
closer to that which the Supreme Court decided was
nonjurisdictional in Sebelius. The statute at issue in that case,
like the review provision here, uses a permissive phrase –
“may obtain a hearing” – before it states the timing
requirement. 17 Compare Sebelius, 568 U.S. at 154, with 47
U.S.C. § 332(c)(7)(B)(v) (“may … commence an action”).
Similar to the timing requirement the Supreme Court held to
be nonjurisdictional in Musacchio, the review provision does
not confer jurisdiction, instead it allows an action to be

       17
           T Mobile also points to Henderson v. Shinseki,
which held a timing requirement to be nonjurisdictional even
though it used the mandatory “shall” before stating the timing
requirement. 562 U.S. 428, 441-42 (2011). But the decision
in Shinseki, where the pertinent timing requirement could
have barred a veteran’s appeal, was partly based on “the
canon that provisions for benefits to members of the Armed
Services are to be construed in the beneficiaries’ favor,” and
so it is of less utility in deciding this dispute. Id. at 441
(quotation marks and citations omitted).




                               26
commenced “in any court of competent jurisdiction.” See
Musacchio, 136 S. Ct. at 717 (“[The provision] does not
expressly refer to subject-matter jurisdiction or speak in
jurisdictional terms.”). The text of the statute therefore favors
a holding that the timing requirement is nonjurisdictional.

       Wilmington next contends that the context of the
timing requirement favors the view that the requirement is
jurisdictional, because the Supreme Court has stated that it is
“inextricably linked to … the language that creates the right
of action[.]” (Answering Br. at 13-14 (citing City of Rancho
Palos Verdes v. Abrams, 544 U.S. 113, 125 (2005)).) Thus,
says the City, the “filing window created by [the review
provision] is jurisdictional [because] it is integral to the
express purpose of the section, to this Court’s jurisdiction,
and to the parties’ rights and obligations[.]” (Answering Br.
at 8.)

       True enough, the review provision’s timing
requirement does appear in the same subsection as the
statutory text granting jurisdiction.             47 U.S.C.
§ 332(c)(7)(B)(v). And, as we stated in Kalb, the Supreme
Court’s decisions in Bowles v. Russell, 551 U.S. 205, 210
(2007), and Reed Elsevier, Inc. v. Muchnick, 559 U.S. at 166,
both found the source of the timing requirement to be
important in determining whether that requirement was
jurisdictional. 891 F.3d at 462. In Kalb, moreover, we made
the same point the City now does, stating that a timing
requirement was jurisdictional because “the thirty-day appeal
period here is embedded in the same statutory section that
grants jurisdiction to the court of appeals.” Id.




                               27
        But the location of the timing requirement within the
statutory structure, without more, does not clearly reveal
Congressional intent. As noted by the Supreme Court in
Sebelius, a timing requirement should not be classified as
jurisdictional solely based on its placement in a jurisdictional
provision. Sebelius, 568 U.S. at 155 (“A requirement we
would otherwise classify as nonjurisdictional … does not
become jurisdictional simply because it is placed in a section
of a statute that also contains jurisdictional provisions.”
(citing Gonzalez v. Thaler, 565 U.S. 134, 146-47 (2012))). In
Musacchio too, the Supreme Court held that a timing
requirement was nonjurisdictional despite its presence in the
jurisdiction-granting section of the statute at issue. 136 S. Ct.
at 717. The Court emphasized that the statute did not directly
speak of the timing requirement as jurisdictional, despite its
mandatory language. Id. That reasoning applies with at least
equal force here, so the context of the review provision’s
timing requirement does not make the requirement
jurisdictional.

       Finally, Wilmington asserts that the timing
requirement is jurisdictional because of the historical
treatment of similar provisions. The City asserts that the
phrase “within 30 days after” creates a “window,” during
which a complaint must be filed, and not a “deadline.”
(Answering Br. at 11-12 (citing W. Union Tel. Co. v. FCC,
773 F.2d 375, 377 (D.C. Cir. 1985)) (noting that “within 60
days after” creates a 60-day filing window while “no later
than 60 days after” creates a filing deadline).) But that
argument misses the point because it goes to whether the rule
bars suit between certain dates or only after a certain date, not
to whether the timing requirement is jurisdictional. See, e.g.,
Union Tel. Co., 773 F.2d at 377-78 (discussing whether the




                               28
filing window is a jurisdictional bar for suits filed before the
window opens). And just because a complaint may be unripe
before a particular date does not mean that a deadline by
which suit must be filed is jurisdictional. As we stated in
Kalb, the Supreme Court’s decisions in Bowles and Reed
Elsevier both looked to “the Court’s prior treatment of
[similar timing requirements.]” Kalb, 891 F.3d at 460. In
Sebelius, the timing requirement, as here, used the phrase
“within” and thus, under Wilmington’s logic, it would have
been a jurisdictional limit. Sebelius, 568 U.S. at 154. But the
Supreme Court held otherwise, id., and that is of high
importance.

         Because the text and context of this statute, and
historical treatment of timing requirements in similar statutes,
do not reveal a clear intent from Congress to make the review
provision’s timing requirement jurisdictional, we conclude
that it is not. 18

       D.     Rule 15 Allows a Supplemental Complaint
              Filed After a Claims Processing Deadline To
              Relate Back and Cure an Unripe Initial
              Complaint.

      We next consider whether an untimely supplemental
complaint can, by relating back, cure an initial complaint that
was unripe. We believe it can, and because T Mobile’s

       18
            That conclusion is further supported by the
thoughtful concurrence in Athens Cellular, concluding after
Sebelius that the timing requirement “imposed by Congress in
the TCA … is not a jurisdictional bar.” Athens Cellular, 886
F.3d at 1113 (Kaplan, J. concurring).




                              29
motion to supplement its complaint was properly granted, that
supplemental complaint relates back and is ripe. The District
Court therefore had jurisdiction and should not have granted
Wilmington’s motion for summary judgment.

        At the outset, we note that the parties do not dispute,
and we agree, that the District Court was within its discretion
to grant T Mobile’s motion to supplement its complaint.
Pursuant to Federal Rule of Civil Procedure 15(d), “[o]n
motion and reasonable notice, the [district] court may, on just
terms, permit a [moving] party to serve a supplemental
pleading setting out any … event that happened after the date
of the pleading to be supplemented.” Fed. R. Civ. P. 15(d);
see also 3 James Wm. Moore et al., Moore’s Federal Practice
¶ 15.30 (3d ed. 2018) (“Supplemental pleadings … are
limited to subsequent events related to the claim or defense
presented in the original pleading.”). Here, the District Court
rightly granted T Mobile’s motion to supplement. That
decision was just, since Wilmington had long since had notice
of the event – the filing of the written denial – that occurred
after the initial pleading. After all, the City issued that denial,
and the denial was featured in the parties’ discovery plan.
The issuance of it was also plainly related to T Mobile’s
initial complaint.

       That the initial complaint was premature is not a bar
since, under Rule 15(d), “[t]he court may permit
supplementation even though the original pleading is
defective in stating a claim for relief or defense.” Fed. R.
Civ. P. 15(d). As the Advisory Committee Notes make clear,
“Rule 15(d) is intended to give the [district] court broad
discretion in allowing a supplemental pleading.” Fed. R. Civ.
P. 15(d) advisory committee’s note to 1963 amendment. It is




                                30
furthermore “within the discretion of the court to allow a
supplemental pleading to be filed at any stage of the case[.]”
Moore et al., supra, ¶ 15.30. The District Court here was thus
well within its discretion in granting T Mobile’s motion to
supplement the complaint.

       Rule 15 does not indicate whether or under what
circumstances a supplemental pleading can relate back to the
date of the original pleading to avoid the effect of a time
limit. 6A Charles Alan Wright et al., Federal Practice &
Procedure § 1508 (3d ed. 2018). Subsection (c) of the Rule,
which provides for the relation back of amended pleadings,
does not specifically refer to supplemental pleadings. Fed. R.
Civ. P. 15(c). Nor does Rule 15(d) make any mention of
relation back. Fed. R. Civ. P. 15(d). But case law and
secondary sources have long instructed that once a
supplemental complaint is granted, it is treated like an
amended complaint for purposes of relation back. 19 Thus,
even though Rule 15(d) is in a separate statutory provision
from Rule 15(c), a supplemental complaint can relate back.
Wright et al., supra, § 1508; see also F.D.I.C. v. Knostman,
966 F.2d 1133, 1138 (7th Cir. 1992) (“The distinction
between an amended pleading and a supplemental pleading is

      19
            Courts have generally held that a supplemental
complaint is eligible for relation back, but rely on different
rationales to do so. See Wright et al., supra, § 1508 (“[S]ome
courts have held that for purposes of applying the relation-
back doctrine a supplemental pleading may be treated as an
amended pleading under Rule 15(c); other courts have
applied the relation-back principle directly to supplemental
pleadings even though Rule 15(d) does not mention it.”)
(internal citations omitted).




                             31
often disregarded for purposes of relation back under Rule
15(c).”); Russell v. New Amsterdam Cas. Co., 303 F.2d 674,
680-81 (8th Cir. 1962) (finding supplemental pleading related
back despite plaintiff suing in the wrong capacity and not
achieving appropriate status for diversity jurisdiction until
after the limitations period had expired). That stands to
reason, since, if a “defendant had notice of the subject matter
of the dispute and was not prejudiced in preparing a defense
…[,] the policy against stale claims becomes subsidiary to the
policy expressed throughout the rules in favor of allowing a
party to set forth all the grievances against another party in
one action and resolving them on their merits.” Wright et al.,
supra, § 1508.

       So a pleading filed according to Rule 15(d) can relate
back, assuming it meets “the basic test for relation back
prescribed by Rule 15(c).” Id.; see also Moore et al., supra,
¶ 15.30 (“A supplemental pleading may relate back to the
date of the original complaint if the requirements under Rule
15(c) for relation back are satisfied”); Davis v. Piper Aircraft
Corp., 615 F.2d 606, 609 n.3 (4th Cir. 1980) (supplemental
pleading relates back if Rule 15(c)’s test is met). In fact, as
the District Court observed, if a supplemental complaint
meets the requirements for relation back then “[r]elation back
is mandatory,” and not subject to additional equitable
considerations. 20 (App. at 6 (citing Arthur v. Maersk, Inc.,
434 F.3d 196, 202-03 (3d Cir. 2006)).)

       20
           We note, however, that “[a] party opposing the
introduction of a supplemental pleading might wish to raise
the statute-of-limitations defense when the additional
pleading (1) alleges new matter that brings the earlier
pleading up to date; (2) cures a defect in the original pleading;




                               32
       Looking then to Rule 15(c), a complaint “relates back
to the date of the original pleading when … [it] asserts a
claim or defense that arose out of the conduct, transaction, or
occurrence set out -- or attempted to be set out -- in the
original pleading[.]” Fed. R. Civ. P. 15(c)(1)(B). The
District Court here concluded that there was no need to
determine whether T Mobile’s supplemental complaint
related back, because, even if it did, “it fail[ed] to cure the
deficiencies of the initial complaint[.]” (App. at 8.) But
given our view that the supplemental complaint could indeed
cure the ripeness problem with the initial complaint, we must
contend with the relation-back question.

        To determine if relation back is proper, the only issue
is whether there is a “common core of operative facts in the
two pleadings.” Bensel v. Allied Pilots Ass’n, 387 F.3d 298,
310 (3d Cir. 2004.) Here, that test is met. Both complaints
rely on the same core facts. The written denial was a
certification and restatement of the earlier oral denial.

      Thus, the only question remaining is whether a
complaint that relates back can cure an untimely initial
complaint, and the answer is yes. The clear preference
embodied in Rule 15 is for merits-based decision making. Cf.
Moore et al., supra, ¶ 15.30 (“The same principles that
support the liberal amendment of pleadings also apply to
supplemental pleadings.”). As the Supreme Court has stated,
the purpose of Rule 15 is “to balance the interests of the


or (3) states a new claim that arose after the filing of the
complaint.” Wright et al., supra, § 1508.




                              33
defendant protected by the statute of limitations with the
preference expressed in the Federal Rules of Civil Procedure
in general, and Rule 15 in particular, for resolving disputes on
their merits.” Krupski v. Costa Crociere S.p.A., 560 U.S. 538,
550 (2010). The requirements of Rule 15 itself protect
defendants from an unfair relation back. 21 Under that Rule,
courts “look[s] to whether the opposing party has had fair
notice of the general fact situation and legal theory upon
which the amending party proceeds.” Bensel, 387 F.3d at
310. In this instance, Wilmington had sufficient notice since
the supplemented complaint simply alleged the issuance of
the ZBA’s written denial. And, of course, Wilmington had
notice of everything in the supplemental complaint. It not
only knew of the written denial and the reasons given, it
generated them.

        Relation back has been allowed to address
jurisdictional problems. We said in Berkshire Fashions, Inc.
v. M.V. Hakusan II that relation back may be used to cure
defects in jurisdictional allegations. 954 F.2d 874, 878 (3rd
Cir. 1992). In that case, the District Court had dismissed the
plaintiff’s claim based on admiralty jurisdiction and denied
the plaintiff’s motion to amend its complaint to allege
diversity jurisdiction. Id. at 877. We concluded that both
decisions were in error, holding that an amended complaint
relates back and can cure insufficient pleading of subject
matter jurisdiction. Id. at 878. Recently, our Circuit allowed

       21
               This is not a pass for endless delay in
supplementing a complaint. Indeed, we have endeavored to
emphasize that whether to allow supplemental pleading
depends on equitable considerations of fairness and notice
that district courts must take into account.




                              34
a plaintiff to cure a diversity defect when the case had been
litigated for years. See GBForefront, L.P., v. Forefront
Mgmt. Grp., LLC, 888 F.3d 29, 32 (3d Cir. 2018)
(“instruct[ing] the [d]istrict [c]ourt to give leave to further
amend the complaint … to cure defective jurisdictional
allegations”).

        Other circuits have held the same. See Woods v. Ind.
Univ.-Purdue Univ. at Indianapolis, 996 F.2d 880, 884 (7th
Cir. 1993) (“Consistent with its history and purpose, Rule
15(c) has uniformly been applied to relate back [filings] that
cure defective statements of jurisdiction ….”); Boyce v.
Anderson, 405 F.2d 605, 607 (9th Cir. 1968) (allowing
amendment alleging that no previous appeal had been taken
to the United States Court of Customs and Patent Appeals to
cure jurisdictional defect in complaint after statute of
limitations had expired). That conclusion is also consistent
with 28 U.S.C. § 1653, which allows “[d]efective allegations
of jurisdiction [to] be amended, upon terms, in the trial or
appellate courts.” Id.

       Courts have similarly permitted cure of actual defects
in the court’s jurisdiction, going beyond just jurisdictional
allegations. For instance, although not in a case involving a
later complaint, the Supreme Court has said that a court can
drop a dispensable non-diverse party to cure a defect in
diversity jurisdiction. Newman-Green, Inc. v. Alfonzo-
Larrain, 490 U.S. 826, 837-38 (1989); see also E.R. Squibb &
Sons, Inc. v. Lloyd’s & Cos., 241 F.3d 154, 163 (2d Cir.
2001) (stating that, “where it is appropriate to relate back an
amendment to a pleading under Rule 15, jurisdiction is
assessed as if the amendment had taken place at the time the
complaint was first filed[,]” and thus replacing a non-diverse




                              35
plaintiff with a diverse plaintiff cured any jurisdiction
problem); Rowe v. United States Fid. & Guar. Co., 421 F.2d
937, 939, 944 (4th Cir. 1970) (concluding that a defective
complaint could be cured by a later complaint that pled an
assignment occurring after the original complaint was filed).

        Nonetheless, “[a]mendments that go beyond the mere
correction or factual modification of the original pleading and
significantly alter the claim or defense alleged in that
pleading are treated more cautiously by the courts in applying
the relation-back doctrine.” Wright et al., supra, § 1497. The
Second Circuit, for instance, only sometimes allows
jurisdictional defects to be cured “when the underlying facts,
if properly pled, would have supported jurisdiction at the time
the action commenced.” Correspondent Servs. Corp. v. First
Equities Corp. of Fla., 338 F.3d 119, 125 (2d Cir. 2003); see
also, e.g., Barton v. Ellis, No. 75-1188, 1977 WL 15469, at
*1 (D.S.C. Apr. 26, 1977) (denying using relation back to
cure the original complaint since they were defects “not [in
the] allegations of existing underlying jurisdictional facts but
rather [in] the prerequisite jurisdictional facts themselves”).
Wilmington argues such hesitance is appropriate here because
allowing relation back to cure the jurisdictional problem with
T Mobile’s initial complaint “would allow two wrongs under
Section 332 [(filing early and filing late)] to make a right.”
(Answering Br. at 2.)

       We again disagree with the City. It is quite true that
T Mobile has made procedural matters more difficult than
they should be in this case. But denying relation-back to cure
the defect in this instance would not comport with Rule 15’s
aim to encourage resolution of disputes on the merits
whenever possible. The ripeness requirement exists so that




                              36
courts avoid issuing essentially advisory opinions. See
Richard H. Fallon, Jr. et al., Hart and Wechsler’s the Federal
Courts and the Federal System 224 (5th ed. 2003) (noting that
the ripeness doctrine allows courts to avoid a “dispute … too
‘ill-defined’ to be appropriate for judicial resolution until
further developments … more sharply framed the issues for
decision.”). That concern ceased to exist here once the
supplemental pleading was in place. At that point, the dispute
had matured and become capable of judicial review,
demonstrating that, “actions taken after the filing of the initial
complaint can be used to establish subject matter
jurisdiction.” Prasco, LLC v. Medicis Pharm. Corp., 537
F.3d 1329, 1337 (Fed. Cir. 2008).

       If a supplemental complaint cannot cure an unripe
complaint, an endless feedback loop would be created
whereby the ripeness problem could never be overcome, even
though, as here, the dispute later became obviously ripe. Our
sister circuits have recognized that problem and concluded
that a supplemental complaint is the solution. 22 In Wilson v.
Westinghouse Electric Corp., the Eighth Circuit determined
that prohibiting an amended (or supplemental) complaint
from alleging facts that occurred after the date the initial

       22
          In our Circuit, a thoughtful district court decision
had long ago reached that conclusion. It held that an
untimely supplement adding facts occurring after the initial
filing that showed exhaustion of administrative remedies
could relate back to the initial premature complaint and allow
maintenance of the lawsuit. Bates v. W. Elec., 420 F. Supp.
521, 526-27 (E.D. Pa. 1976).




                               37
complaint was filed would turn a premature complaint into an
“irretrievable mistake that bars jurisdiction” and would be
“precisely the kind of procedural mousetrap that the Federal
Rules were designed to dismantle.” 838 F.2d 286, 289 (8th
Cir. 1988). The court held that, “[e]ven when the District
Court lacks jurisdiction over a claim at the time of its original
filing, a supplemental complaint may cure the defect by
alleging the subsequent fact which eliminates the
jurisdictional bar.” Id. at 290 (citing Mathews, 426 U.S. at
75). While Wilson addressed a circumstance in which the
supplemental complaint was timely filed, the proposition still
applies in a case like ours because, if a party was limited to
refiling within an applicable time limit, there would be little
need to make provision for supplementation of a complaint,
as a new complaint could be filed. 23

       23
            We note that sparing the cost of refiling and
providing convenience to the Court would remain legitimate
reasons for allowing supplemental complaints. But the
purpose of Rule 15(d) is broader. See Wright et al., supra, §
1504 (“The purpose of subdivision (d) is to promote as
complete an adjudication of the dispute between the parties as
is possible. … A supplemental pleading may be employed
for a variety of purposes.”). Wilmington contends that
Wilson is inapposite since it involved a timely supplemental
complaint. Thus, concern about a perpetual loop outcome
was not proper because the plaintiff could have simply refiled
his complaint. But we agree that “a plaintiff need not
commence a new action when after-occurring events
demonstrate that it has a right to relief even if the original
complaint was insufficient. A plaintiff may also be allowed
to supplement the complaint even if jurisdiction … would not
have been proper if the claim had been asserted in an




                               38
        The Ninth Circuit, in Security Insurance Co. of New
Haven v. United States ex rel. Haydis, also relied on that logic
to find that relation back could cure an unripe complaint filed
before a statutory filing window opened. 338 F.2d 444, 448-
49 (9th Cir. 1964). In a fact scenario with striking similarities
to the present appeal, the plaintiff had filed its claim before a
statutory waiting period was over and then did not file an
amended complaint until after the statute of limitations period
had run. Id. at 445-46. The appeals court held that the
district court was “not required to apply the doctrine of
relation back so literally as to carry it to a time [before it was
ripe] so as to prevent the maintenance of the action in the first
place.” Id. at 449.

       The Supreme Court has favorably cited Security
Insurance’s ruling. In Mathews, the plaintiff had not satisfied
a precondition of filing a complaint by first filing an
application with a particular agency. 426 U.S. at 72, 75. The
Court noted that a supplemental complaint, alleging that the
application had since been filed, would have cured the
jurisdictional defect. Id. at 75. In saying so, the Court relied



independent action.” Moore et al., supra, ¶ 15.30 (3d ed.
2018) (citation omitted). If supplemental complaints could
not cure ripeness, “then all supplemental pleadings of this
nature would be defeated for lack of jurisdiction – [the]
‘procedural mousetrap’ would render all supplemental
pleadings void.” George v. IRS, No. C05-00955 MJJ, 2006
WL 3499230, at *3 (N.D. Cal. Dec. 4, 2006) (citation
omitted).




                               39
on Security Insurance. Id. at 75 n.8 (citing Security
Insurance, 338 F.2d at 447-49). 24

       Yet Wilmington asserts that ripeness can never be
cured by a later complaint. It advances four cases for that
proposition, but none are helpful. First, the City cites
Delaware Riverkeeper Network v. Secretary Pennsylvania
Department of Environmental Protection, (Riverkeeper I),
833 F.3d 360 (3d Cir. 2016), in which we concluded that,
“even though the underlying claim became ripe for review
during the pendency of the case, the ripening of the claim did
not cure deficient pleadings.” (App. at 8.) In that case,
however, no attempt to file a later complaint alleging ripeness
was made. Riverkeeper I, 833 F.3d at 369-70.

        Likewise, in another two of the four cases that
Wilmington cites, there was no effort made to amend or
supplement the complaint. See TeleSTAR, Inc. v. FCC, 888
F.2d 132, 134 (D.C. Cir. 1989) (concluding non-final agency
action at the time of filing of petition may only be reviewed
upon the filing of another petition); W. Union Tel. Co., 773
F.2d at 377-78 (concluding that the court lacked jurisdiction
over challenges filed before the action became final).
Therefore, neither case determined whether relation back of a
later-filed complaint could cure a ripeness problem in the
initial complaint.

       24
           Wilmington contends that Mathews is inapposite
since the statute of limitations was waived. That argument
has no traction since, if it were a jurisdictional bar, it could
not be waived.




                              40
        The City fares no better relying on Council Tree
Communications v. FCC, in which we stated that “[a] petition
to review a non-final agency order is incurably premature.”
503 F.3d 284, 291 (3d Cir. 2007). At no point in that case
was the complaint ripe, and the petitioner still had a petition
for reconsideration pending before the relevant agency on the
date the case was decided. Id. at 287. Furthermore, Council
Tree explicitly acknowledged that a supplemental complaint
can cure an unripe complaint when there is jurisdiction over
that supplemental pleading. See id. at 291 (“[W]e note that
‘nothing prevented [the petitioners] from supplementing their
premature petition with a later protective petition.’” (second
alteration in original) (quoting Horsehead Res. Dev. Co. v.
E.P.A., 130 F.3d 1090, 1095 (D.C. Cir. 1997))).

        Wilmington also makes three policy arguments in
support of its position that an untimely supplemental
complaint should not be able to cure an unripe complaint.
First, it contends that allowing suits to be filed before an
action is ripe would “extend[] federal court jurisdiction over
local government actions before those actions are final[.]”
(Answering Br. at 9.) Second, such filings would waste
judicial resources and, in this case, cost taxpayers money, by
forcing courts to deal with a higher volume of unripe
complaints. Third, the purpose of § 332 is to preserve local
zoning authority, which would be undermined by allowing
plaintiffs to file suit early and thereby places undue pressure
on zoning commissions.

       Those contentions, however, are unpersuasive. First, a
court would remain without jurisdiction if the claim had not
ripened by the time of the supplemental complaint. Second, it




                              41
seems that Wilmington overstates the impact that a decision
allowing an unripe complaint to be cured would have, since
our holding today makes it clear that an action is not final
until a written decision has been issued. Clarifying when a
determination is ripe for review should end any incentive for
aggrieved parties to file early to ensure they have not filed too
late.

         Perhaps more importantly, however, courts can police
any potential abuse on a case-by-case basis using Rule 15(d)
and the Rule 15(c) test for relation back. It is understood that
“relation back of a supplemental pleading should not result in
providing unfair procedural advantages to a plaintiff[,] so …
relation back may not be for all purposes.” Wright et al.,
supra, § 1508. But here no unfair advantage has resulted, and
defendants in general will be adequately protected by a
district court’s Rule 15(d) analysis, which will determine if a
supplemental complaint should be allowed at all. For
instance, if a locality’s action is not yet a final action at the
time a Rule 15(d) motion is filed, the motion can easily be
denied. See Beezley v. Fremont Indem. Co., 804 F.2d 530,
530 (9th Cir. 1986) (supplemental pleading denied when it
still failed to cure defective original pleading).

        When all is said and done here, we conclude that, to
effectuate the liberal purpose of Rule 15 and to avoid the
endless feedback loop that the City’s legal argument would
create, Rule 15 allows an untimely supplemental complaint to
relate back and cure an unripe initial complaint.




                               42
III.   CONCLUSION

       For the foregoing reasons, we will reverse the District
Court’s grant of the City’s motion for summary judgment,
vacate the District Court’s denial of T Mobile’s motion for
summary judgment, and remand to the District Court for
further proceedings consistent with this opinion.25




       25
           We will vacate the District Court’s denial of
T Mobile’s motion for summary judgment because it was
solely based on a finding that T Mobile’s suit was not timely
brought.




                             43
