                     FOR PUBLICATION

   UNITED STATES COURT OF APPEALS
        FOR THE NINTH CIRCUIT


 TIMOTHY P. DEMARTINI; MARGIE                    Nos. 17-16400
 DEMARTINI,                                           18-15882
               Plaintiffs-Appellees,
                                                     D.C. No.
                     v.                           2:14-cv-02722-
                                                    JAM-CKD
 MICHAEL J. DEMARTINI; RENATE
 DEMARTINI,
             Defendants-Appellants.                  OPINION

        Appeal from the United States District Court
            for the Eastern District of California
         John A. Mendez, District Judge, Presiding

         Argued and Submitted December 11, 2019
                   Pasadena, California

                          Filed July 6, 2020

  Before: Diarmuid F. O’Scannlain and Richard A. Paez,
  Circuit Judges, and Michael H. Simon, * District Judge.

                Opinion by Judge O’Scannlain



    *
      The Honorable Michael H. Simon, United States District Judge for
the District of Oregon, sitting by designation.
2                  DEMARTINI V. DEMARTINI

                          SUMMARY **


                     Jurisdiction / Remand

    The panel dismissed an appeal seeking review of the
district court’s order remanding back to state court a
partnership dissolution claim in an action that was originally
filed in state court and removed to federal court.

    During discovery, a report showed that a parcel of the
property at issue was held by a partnership that included a
trustee that destroyed the previously complete diversity of
the parties. The district court determined that the partnership
dissolution claim could not proceed without joinder of the
trustees, but the other claims could proceed without joinder.
The district court acknowledged that Fed. R. Civ. P. 19(b)
would ordinarily require it to dismiss the action, but the
district court determined that 28 U.S.C. § 1447(e) authorized
the alternative of remand. The district court severed the
partnership dissolution claim from the rest of the case, and
remanded only that claim for resolution in state court.

    28 U.S.C. § 1447(d) states that “[a]n order remanding a
case to the State court from which it was removed is not
reviewable on appeal or otherwise.”

    The panel held that § 1447(d)’s prohibition of appellate
review applied to this appeal, and rejected appellants’
arguments to the contrary. First, appellants argued that
§ 1447(d)’s limitation on the review of remand orders should

    **
       This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
                 DEMARTINI V. DEMARTINI                      3

be construed to apply only to remand orders issued pursuant
to § 1447(c) and not, as here, § 1447(e). The panel held that
§ 1447(d) deprived the court of jurisdiction to review
remand orders that were issued pursuant to § 1447(e) and
that invoked the grounds specified in that subsection.
Second, the panel held that appellants’ accusation of legal
error – that the district court erroneously concluded that the
joinder of trustees destroyed the parties’ diversity – did not
permit this court to sidestep the command of § 1447(d).
Third, appellants contended that § 1447(d) did not bar this
court’s review of this remand order because the district court
remanded a single claim to state court, while § 1447(d)
prevented the review of orders remanding a case. The panel
held that this argument ignored that the effect of the district
court’s severance of the dissolution claim from the other
claims was to create a separate case – a case that it then
remanded.

    Appellants also asserted that the joinder that occasioned
the remand was separable from the remand. An antecedent
determination is separable from the remand order when it (1)
preceded the remand order in logic and fact; and (2) was
conclusive, i.e. functionally unreviewable in state courts.
City of Waco v. United States Fidelity & Guaranty Co., 293
U.S. 140 (1934). At step one, the panel held that the
antecedent determination was not a City of Waco-type
dismissal of all claims against the diverse party, but rather
the joinder of a diversity-destroying party. Section 1447(e)
did not permit separate consideration of joinder and remand
because they were one and the same. The panel also held that
the district court’s joinder of the trustees failed to meet the
second requirement: that the antecedent order be conclusive
on the issue it decided. The panel concluded that, because
the state court may dismiss the trustees, the joinder in this
case is not conclusive and hence not reviewable.
4                DEMARTINI V. DEMARTINI

    In holding that the joinder of a diversity-destroying party
was not separable from a § 1447(e) remand order and was
therefore unreviewable, the panel joined the Fourth Circuit,
and differed from the Fifth and Third Circuits, which had
distinguishable cases.

    The panel held that it need not decide whether § 1447(d)
barred review of pre-remand decisions to sever claims
because appellants expressly waived any objection on the
merits of the district court’s severance of the partnership
dissolution claim.

    The panel held that mandamus relief was an
extraordinary remedy that was neither warranted nor
permissible here.

   The panel addressed the parties’ related appeals in a
memorandum disposition filed concurrently with this
opinion.


                         COUNSEL

Kathryn M. Davis (argued), Law Office of Kathryn M.
Davis, Pasadena, California, for Defendants-Appellants.

David B. Dimitruk (argued), Law Offices of David B.
Dimitruk, Tustin, California, for Plaintiffs-Appellees.
                 DEMARTINI V. DEMARTINI                      5

                         OPINION

O’SCANNLAIN, Circuit Judge:

    This case originated in state court, was removed to
federal court, and subsequently was remanded back to state
court. We are called upon to decide whether we have
jurisdiction, nevertheless, to review the district court remand
order that also amended the complaint to add a diversity-
destroying defendant and severed the affected claim for
disposition in state court.

                               I

                              A

    Timothy and Michael DeMartini are brothers who, along
with their wives, co-own adjacent commercial properties in
Grass Valley, California. The first parcel, 12731 Loma Rica
Drive (“the 12731 parcel”), is held by DeMartini & Sons, an
oral partnership formed in the late 1970s by Timothy,
Michael, and their father, James Paul DeMartini. The nature
of the brothers’ joint ownership of the second parcel, 12759
Loma Rica Drive (“the 12759 parcel”), is contested.
Michael and his wife Renate DeMartini claim that the parcel
is also held by a partnership, but Timothy and his wife
Margie DeMartini claim that the parcel is held by the couples
as tenants in common.

    Seeking to fund further development of the 12759 parcel,
Timothy, Margie, Michael, and Renate took out a $250,000
loan from Westamerica Bank in 1998. When the loan came
due in 2014, Michael and Renate wanted to extend the due
date but Timothy and Margie did not. After a short
extension, Timothy and Margie unilaterally paid the loan’s
$137,212.51 outstanding balance. Claiming that the couples
6                 DEMARTINI V. DEMARTINI

had an agreement to share the burden of the loan fifty-fifty,
Timothy and Margie demanded that Michael and Renate pay
their share. Michael and Renate refused, asserting that the
12759 parcel was held by a partnership and that Timothy and
Margie’s unilateral action breached the partnership
agreement. Michael and Renate also claimed that Timothy
and Margie had closed a partnership bank account and
diverted income from the 12759 parcel to their personal
account. Hence, in Michael and Renate’s view, Timothy and
Margie were required to apply the diverted accrued income
from the 12759 parcel to the outstanding debt before asking
Michael and Renate to cover half of the remainder.

                                B

    Timothy and Margie DeMartini filed this lawsuit against
Michael and Renate in California Superior Court on
September 15, 2014. Michael and Renate promptly removed
the case to federal district court, citing diversity jurisdiction.
See 28 U.S.C. §§ 1332, 1441(a). The parties are completely
diverse. Timothy and Margie are citizens of California,
which is also where the Loma Rica Drive parcels are located,
while Michael and Renate are citizens of Nevada.

    A year after this case was filed and removed, the district
court granted Timothy and Margie leave to amend their
original complaint. Timothy and Margie now assert three
claims for relief: (1) dissolution of the partnership that owns
the 12731 parcel, (2) partition of the 12759 parcel, which
they alleged was owned by the couples as tenants in common
rather than as partners, and (3) damages for Michael and
Renate’s alleged breach of the contract to share half the
obligation of the Westamerica loan. In response, Michael
and Renate amended their answer and counterclaim,
asserting several affirmative defenses and seeking
declaratory relief and damages.
                 DEMARTINI V. DEMARTINI                      7

                              C

    The case proceeded to discovery. In late 2016, Timothy
and Margie received a litigation guarantee report for the
12731 parcel that showed that the property was held by a
partnership consisting of three titled partners: Timothy,
Michael, and their deceased father, James Paul DeMartini.
This revelation contradicted the first amended and then-
operative complaint, which had alleged that Timothy and
Michael had succeeded to their father’s one-third share of
the partnership assets. After further research, Timothy and
Margie’s attorneys determined that the James Paul
DeMartini testamentary trust retained an interest in the
partnership. On February 17, 2017—less than a week before
the discovery cut-off—Timothy and Margie moved further
to amend their complaint to join the trustees of their father’s
estate as defendants to the partnership dissolution claim.
One such trustee is Michael and Timothy’s brother, James
C. DeMartini, a citizen of Colorado and, thus, not a threat to
the district court’s diversity jurisdiction. The other trustee,
however, is Timothy. Adding him as a defendant not only
causes a curious scenario in which Timothy in his individual
capacity is potentially adverse to himself in his capacity as
trustee; it also destroys the previously complete diversity of
the parties.

    The district court concluded that, due to the trust’s
interest in the 12731 parcel, it could not “in equity and good
conscience” allow the partnership dissolution claim to
proceed without joining the trustees as parties, thus
destroying diversity. The other claims could proceed
without joinder. Neither party claimed the trustees had an
interest in the adjacent 12759 parcel, which was the subject
of Timothy and Margie’s partition action. Nor did they
claim the trust to be a party to the alleged contract that
8                DEMARTINI V. DEMARTINI

formed the basis of Timothy and Margie’s breach of contract
claim or to the alleged broader partnership that formed the
basis of Michael and Renate’s counterclaims.

     Rather than dismiss the action or remand the entire case
upon the joinder of the trustees, the district court decided on
a third option. Noting that the case had been “vigorously
litigated” and “a significant amount of judicial resources
[had] been invested” during the two years before Timothy
and Margie’s attorneys received the litigation guarantee
report, the district court determined that the “means best
suited to accommodate the interests of all parties, and
proposed parties,” would be to sever the partnership
dissolution claim from the rest of the case and to remand
only that claim for resolution in state court.

    Accordingly, in a single decree, the district court granted
the motion to amend to add the trustees, severed the
partnership dissolution claim, and remanded that claim to
California Superior Court.

                              D

    Michael and Renate appeal the order amending,
severing, and remanding the partnership dissolution claim
(“the Order”) (No. 17-16400). On its own, of course, such
an order is not immediately appealable as either a final
decision within the meaning of 28 U.S.C. § 1291 or under
the collateral order exception. Stevens v. Brink’s Home Sec.,
Inc., 378 F.3d 944, 947–48 (9th Cir. 2004).

    However, after the summary judgment on all three
counterclaims had been entered and a jury verdict on the
breach of contract claim rendered, the district court directed
entry of a Rule 54(b) partial final judgment. Michael and
Renate now also appeal from that judgment and from the
                 DEMARTINI V. DEMARTINI                     9

denial of their post-trial motion for judgment as a matter of
law or a new trial (No. 18-15882). This court then
consolidated the appeal from the Order (No. 17-16400) with
the subsequent appeal from the Rule 54(b) judgment and
denial of the post-trial motion (No. 18-15882).

   Before us, then, is the district court’s order amending the
complaint to add the trustees, severing the dissolution claim,
and remanding it to state court. We address Michael and
Renate’s appeal from the entry of judgment on their three
counterclaims and on Timothy and Margie’s breach of
contract claim in a memorandum disposition filed
concurrently with this opinion. See DeMartini v. DeMartini,
Nos. 17-16400 & 18-15882, — F. App’x — (9th Cir. 2020).

                              II

    The parties dispute whether we have jurisdiction to
review the Order. Timothy and Margie assert that 28 U.S.C.
§ 1447(d) bars our review of the Order, while Michael and
Renate contend that we have jurisdiction over it in its
entirety.

                              A

    Section 1447(d) states that “[a]n order remanding a case
to the State court from which it was removed is not
reviewable on appeal or otherwise,” with certain defined
exceptions not relevant here. 28 U.S.C. § 1447(d).

    In addition, § 1447, which governs procedure after
removal, provides two separate authorizations for a district
court’s remand of a removed case. First, § 1447(c) stipulates
that:
10               DEMARTINI V. DEMARTINI

        A motion to remand the case on the basis of
        any defect other than lack of subject matter
        jurisdiction must be made within 30 days
        after the filing of the notice of removal . . . .
        If at any time before final judgment it appears
        that the district court lacks subject matter
        jurisdiction, the case shall be remanded.

Id. § 1447(c). In other words, the district court may remand
to state court only upon timely motion, unless there appears
to be a defect in subject-matter jurisdiction, in which case
the court must remand no matter the stage of the
proceedings.

     Second, § 1447(e) provides:

        If after removal the plaintiff seeks to join
        additional defendants whose joinder would
        destroy subject matter jurisdiction, the court
        may deny joinder, or permit joinder and
        remand the action to the State court.

Id. § 1447(e). Section 1447(e) addresses a lacuna in Federal
Rule of Civil Procedure 19. When the joinder of a required
party is not feasible because it would deprive the district
court of subject-matter jurisdiction, Rule 19 directs the court
to “determine whether, in equity and good conscience, the
action should proceed among the existing parties or should
be dismissed.” Fed. R. Civ. P. 19(b). Section 1447(e) allows
a third option: remand back to state court. See Yniques v.
Cabral, 985 F.2d 1031, 1034 (9th Cir. 1993) (“Section
1447(e) engineers a ‘departure’ from the analysis required
by Fed. R. Civ. P. 19 in that it allows the joinder of a
necessary non-diverse party and a subsequent remand to
state court.”).
                 DEMARTINI V. DEMARTINI                    11

    This appeal concerns a remand order citing § 1447(e) as
its basis. After concluding that, “in equity and good
conscience,” it could not allow the action to proceed without
the trustees, the district court acknowledged that Rule 19
would ordinarily require it to dismiss the action. However,
because the case had been removed from state court, the
district court determined that § 1447(e) authorized the
alternative of remand, an alternative which it welcomed.

                              B

   Michael and Renate offer several options by which we
could purportedly find an exception to § 1447(d)’s seeming
prohibition on our review of the Order.

                              1

    First, Michael and Renate urge that § 1447(d)’s
limitation on the review of remand orders should be
construed to apply only to remand orders issued pursuant to
§ 1447(c) and not, as here, § 1447(e). Although the Supreme
Court once held that § 1447(d) must be read together with
§ 1447(c) such that “only remand orders issued under
§ 1447(c) and invoking the grounds specified therein . . . are
immune from review under § 1447(d),” Thermtron Prods.,
Inc. v. Hermansdorfer, 423 U.S. 336, 346 (1976), Congress
has since amended the statute to broaden subsection (c) and
to add subsection (e), see H.R. 4807, 100th Cong. § 1016
(1988). Accordingly, in Stevens, we concluded that
§ 1447(d) deprives us of jurisdiction to review remand
orders that were issued pursuant to § 1447(e) and that invoke
the grounds specified in that subsection. 378 F.3d at 948–
12                  DEMARTINI V. DEMARTINI

49. 1 Every other circuit to consider the question agrees. See,
e.g., Fontenot v. Watson Pharm., Inc., 718 F.3d 518, 520–21
(5th Cir. 2013); Blackburn v. Oaktree Capital Mgmt., LLC,
511 F.3d 633, 636–37 (6th Cir. 2008); Alvarez v. Uniroyal
Tire Co., 508 F.3d 639, 641 (11th Cir. 2007); In re Fla. Wire
& Cable Co., 102 F.3d 866, 868–69 (7th Cir. 1996);
Washington Suburban Sanitary Comm’n v. CRS/Sirrine,
Inc., 917 F.2d 834, 836 n.5 (4th Cir. 1990).

    Michael and Renate assert that remands pursuant to
§ 1447(e) are discretionary and therefore reviewable, unlike
remands pursuant to § 1447(c), which they say are

      1
        In Stevens, our court decided that § 1447(d) is equally an
impediment to review of remands under § 1447(e) as it is to review of
remands under § 1447(c) without yet having had the benefit of the
Supreme Court’s discussion of the interrelationship between these three
subsections in Powerex Corp. v. Reliant Energy Servs., Inc., 551 U.S.
224 (2007). The discussion in Powerex provides another persuasive
rationale for our holding in Stevens. As the Supreme Court made clear,
Congress’s addition of § 1447(e) was part and parcel of its broadening
of the district court’s authority to remand under § 1447(c). See id.
at 231–32. Before 1988, § 1447(c) mandated remand to state court only
for cases that had been improperly removed to federal court—i.e., cases
in which there was a defect in subject-matter jurisdiction at the time of
removal or in which the removal was procedurally improper. See id.
at 231; Thermtron, 423 U.S. at 342. When § 1447(c) was broadened to
authorize remands for cases with apparent defects in subject-matter
jurisdiction even if the cases were properly removed, § 1447(e) was
added to extend such a rule expressly to the circumstance of required,
diversity-destroying joinder. In the absence of § 1447(e), an arguably
incoherent rule would govern. Namely: a case removed under federal
diversity jurisdiction in which an indispensable party appeared to be
nondiverse must be remanded, unless that indispensable party had yet to
be joined as a party to the action, in which case the district court would
be required to dismiss the action under Rule 19, even late in the course
of litigation and after the statute of limitations had expired. See Yniques,
985 F.2d at 1034–35; 14C Charles Alan Wright & Arthur R. Miller,
Federal Practice & Procedure § 3739.1 (Rev. 4th ed. 2020).
                 DEMARTINI V. DEMARTINI                     13

mandatory and therefore unreviewable. Such argument
confuses the nature of the district court’s discretion under
§ 1447(e), and we rejected it in Stevens. 378 F.3d at 948–
49.

    Section 1447(c) remands are mandatory because once it
appears that the district court lacks subject-matter
jurisdiction the court must remand. But those under
§ 1447(e) are also mandatory because, once the diversity-
destroying defendant has been joined under that subsection,
the district court’s only option is to remand. Likewise, if the
district court does not join the diversity-destroying
defendant, § 1447(e) does not authorize remand. As we
explained in Stevens, it is the joinder that is discretionary,
not the remand. Id. at 949.

    Michael and Renate respond that Stevens is no longer
good law because it was sub silentio overruled by the more
recent case of Lively v. Wild Oats Mkts., Inc., 456 F.3d 933
(9th Cir. 2006). Lively was as much bound by Stevens as we
are bound by them both. See Hart v. Massanari, 266 F.3d
1155, 1171 (9th Cir. 2001) (“[A] later three-judge panel
considering a case that is controlled by the rule announced
in an earlier panel’s opinion has no choice but to apply the
earlier-adopted rule; it may not any more disregard the
earlier panel’s opinion than it may disregard a ruling of the
Supreme Court.”).

   We again conclude that, no matter whether the district
court issued the remand pursuant to § 1447(c) or, as here,
pursuant to § 1447(e), § 1447(d)’s bar applies.

                              2

    Second, Michael and Renate argue that § 1447(d) does
not apply to review of this Order because, in their view, the
14                   DEMARTINI V. DEMARTINI

district court’s conclusion that the joinder destroyed the
parties’ diversity was legal error. Although the caption of
Timothy and Margie’s proposed amended complaint listed
Timothy, in his capacity as a trustee, as a defendant, Michael
and Renate contend that the motion to join him as a party
should have been read to add him as a plaintiff. They also
contend that the district court failed to consider the full set
of factors that govern the joinder of a diversity-destroying
party.

    It would negate § 1447(d) to hold (as Michael and
Renate seem to propose) that a court may review the merits
of a remand order when that court suspects any legal error.
Nonetheless, appellate courts may peek at the remand order
as part of our “jurisdiction to determine our own
jurisdiction.” Lively, 456 F.3d at 937 (quoting Special Invs.,
Inc. v. Aero Air, Inc., 360 F.3d 989, 992 (9th Cir. 2004)).
Accordingly, we take note of the grounds upon which the
district court professes to base its remand. When the district
court characterizes its remand as “resting upon lack of
subject-matter jurisdiction”—as all § 1447(e) remands
must—the appellate court’s review, “to the extent it is
permissible at all, should be limited to confirming that that
characterization was colorable.” Powerex, 551 U.S. at 234.
Once the appellate court determines that “the District Court
relied upon a ground that is colorably characterized as
subject-matter jurisdiction, appellate review is barred by
§ 1447(d).” Id. 2

     2
       Powerex raises the possibility that § 1447(d) would permit
appellate review of a remand order that “dresses in jurisdictional clothing
a patently nonjurisdictional ground,” but holds off on deciding whether
such review is permissible. Powerex, 551 U.S. at 234. We need not
decide either, as it is not alleged here that the district court’s concern for
diversity jurisdiction was a façade.
                 DEMARTINI V. DEMARTINI                     15

    It would appear that Michael and Renate conflate review
of whether the grounds of the remand order were colorably
based on lack of subject-matter jurisdiction, which is
permitted, with review of whether the remand was an
acceptable exercise of such authority, which is not. See, e.g.,
Lively, 456 F.3d at 938 (“[T]he question raised on appeal is
not whether the district court’s remand order was correct, but
whether the district court exceeded the scope of its § 1447(c)
authority by issuing the remand order in the first place.”).
As a result, Michael and Renate rely on precedents in which
this court reviewed district court remand orders that were not
even ostensibly grounded in lack of subject-matter
jurisdiction. E.g., Smith v. Mylan, Inc., 761 F.3d 1042, 1044
(9th Cir. 2014) (untimely removal); Harmston v. City &
County of San Francisco, 627 F.3d 1273, 1277 (9th Cir.
2010) (discretionary refusal of supplemental jurisdiction);
Lively, 456 F.3d at 942 (forum defendant rule); Kelton Arms
Condo. Owners Ass’n, Inc. v. Homestead Ins. Co., 346 F.3d
1190, 1193 (9th Cir. 2003) (defect in removal procedure);
Garamendi v. Allstate Ins. Co., 47 F.3d 350, 352 (9th Cir.
1995) (Burford abstention).

    Here, the Order was premised on the concern that the
proposed joinder would “destroy diversity.” There is no
dispute here whether such grounds are colorably
jurisdictional or are simply procedural as there was in, say,
Lively. By definition, diversity confers subject-matter
jurisdiction and so the addition of a diversity-destroying
defendant would “destroy subject matter jurisdiction” in this
case. 28 U.S.C. § 1447(e).

    Because the district court characterized the remand as
compelled by the grounds specified by § 1447(e), “review is
unavailable no matter how plain the legal error in ordering
the remand.” Kircher v. Putnam Funds Tr., 547 U.S. 633,
16               DEMARTINI V. DEMARTINI

641–42 (2006) (quotation marks omitted). The accusation
of legal error does not permit this court to sidestep the
command of § 1447(d).

                              3

    Finally, Michael and Renate contend that § 1447(d) does
not bar our review of this remand order because the district
court remanded a single claim to state court, while § 1447(d)
prevents the review of orders “remanding a case.” 28 U.S.C.
§ 1447(d) (emphasis added). Such an argument ignores that
the effect of the district court’s severance of the dissolution
claim from the other claims was to create a separate case—
a case that it then remanded. See Herklotz v. Parkinson,
848 F.3d 894, 898 (9th Cir. 2017) (“When a claim is severed,
it becomes an entirely new and independent case” with “an
independent jurisdictional basis.”).

   We therefore conclude that § 1447(d)’s prohibition
applies to this appeal.

                              III

    Section § 1447(d)’s bar on our review of the remand
does not end this case. Michael and Renate also assert that
the joinder that occasioned the remand is separable from the
remand. A reviewing court, they remind us, may look
behind the unreviewable remand order and review the
district court’s antecedent determinations when such
determinations are separable from the remand order. See
Stevens, 378 F.3d at 946.

                              A

   The separability doctrine originated in the Supreme
Court’s terse, cryptic, and now-controversial opinion in City
                    DEMARTINI V. DEMARTINI                           17

of Waco v. United States Fidelity & Guaranty Co., 293 U.S.
140 (1934). 3 There, an individual, filing in state court, sued
the City of Waco and its contractor for damages that he
suffered in a collision with a street obstruction. Id. at 141.
The City then brought a cross-complaint against the United
States Fidelity & Guaranty Company (“USF&G”), an out-
of-state surety. Id. USF&G removed the case to federal
court, but, on motion from the plaintiff, the federal district
court dismissed the cross-complaint and, finding the parties
no longer diverse, remanded the case to state court. Id.
at 141–42. The appellate court held that it did not have
jurisdiction over the order dismissing the cross-claim, but
the Supreme Court reversed. Id. at 142–43. The Court held
that the dismissal of the cross-claim was reviewable because
“in logic and in fact the decree of dismissal preceded that of
remand” and, “if not reversed or set aside, is conclusive upon
the petitioner.” Id. at 143. Yet the Court took pains to make
clear that the review of the dismissal would not be a back
door through which the appellate court could review the
remand of the rest of the case. Id. at 143–44.

                                   B

    In dicta, our court has distilled City of Waco’s criteria for
a separable antecedent determination into a two-step test.
An antecedent determination is separable from the remand
order when it (1) “preceded the remand order in logic and
fact” and (2) is “conclusive, i.e., functionally unreviewable
in state courts.” Stevens, 378 F.3d at 946 (quoting Dahiya v.
    3
      City of Waco preceded the enactment of § 1447(d) and the Federal
Rules of Civil Procedure, so the Supreme Court, while continuing to
apply and interpret the precedent, has recently cast doubt on the
“continued vitality” of the limited appellate review it allows. Kircher,
547 U.S. at 645 n.13; see also In re C & M Props., L.L.C., 563 F.3d 1156,
1164 (10th Cir. 2010) (Gorsuch, J.).
18               DEMARTINI V. DEMARTINI

Talmidge Int’l, Ltd., 371 F.3d 207, 210 (5th Cir. 2004)). We
have had very few occasions to employ and to develop the
separability doctrine, so City of Waco remains the exemplar
case of a separable order.

                              1

    Let’s begin with step one: whether the antecedent
determination preceded the remand order “in logic and fact.”
Here the antecedent determination is not a City of Waco-type
dismissal of all claims against the diverse party, but rather
the joinder of a diversity-destroying party.

    While the joinder of the trustees undoubtedly preceded
the remand of the partnership dissolution claim in logic, it is
not clear whether the joinder preceded the remand in fact.
Recall that the remand was ordered pursuant to § 1447(e).
Under that subsection, the district court has two options:
either deny joinder or join-and-remand. Section 1447(e)
does not permit separate consideration of joinder and
remand; they are one and the same.

    We are not persuaded that City of Waco attached such
significance to its comment that “in logic and fact the decree
of dismissal preceded that of remand” that we should read
“logic” and “fact” as such separate, demanding
requirements. City of Waco, 293 U.S. at 143. Indeed, the
district court in City of Waco issued its dismissal and its
remand in a “single decree,” so even simultaneous orders in
a single decree may be separable. Id. at 142. The orders
before us were also issued simultaneously and in a single
decree. We see nothing about their sequence that merits a
different treatment than the orders in City of Waco.

     We therefore proceed to step two.
                 DEMARTINI V. DEMARTINI                       19

                               2

    The district court’s joinder of the trustees clearly fails to
meet the second requirement: that the antecedent order be
“conclusive” on the issue it decided. A “conclusive”
antecedent order is one that is “functionally unreviewable in
state court.” Stevens, 378 F.3d at 946. Put another way, a
separable order “result[s] in substantive issues being later
barred.” Washington Suburban Sanitary Comm’n, 917 F.2d
at 836 n.4. The order dismissing the cross-claim in City of
Waco illustrates the point. There the City could not bring
the same cross-claim in state court because the district
court’s dismissal had preclusive effect. City of Waco,
293 U.S. at 143.4 The Court was therefore concerned that
the City’s cross-claim would be extinguished simply
because it fell into a limbo in which the district court’s
dismissal was simultaneously unreviewable in federal court
and preclusive in state court.

    Here no such concern is warranted. No claims will be
functionally extinguished by our inability to review the
challenged amendment. Instead, the full and ultimate effect
of the amendment is that one of the six claims pled in this
case must now be resolved in a state forum instead of a
federal one. Unlike City of Waco, the state court is not bound
by the challenged amendment. If the trustees should not
have been joined, the courts of the State of California are
free to dismiss them. See Kircher, 547 U.S. at 646 (“[W]hat
a state court could do in the first place it may also do on
remand.”).



    4
      It would have no such effect today. See In re C & M Props.,
563 F.3d at 1165.
20               DEMARTINI V. DEMARTINI

    But Michael and Renate contend that the joinder is
unreviewable in state court because the state court possesses
“no power to reverse remand.” However, the crucial
“conclusive” result cannot be the remand itself; otherwise it
would contradict the very premise of the separability
doctrine, which is that some orders have effects that render
such orders separable from the remand. Whether the joinder
is conclusive therefore cannot depend on whether the state
court may reverse the remand; it must depend on whether
the state court may reverse the joinder and dismiss the
trustees.

    We conclude that, because the state court may dismiss
the trustees, the joinder in this case is not conclusive and
hence not reviewable.

                              3

    Furthermore, we are reminded that City of Waco
“repeatedly cautioned that the remand order itself could not
be set aside” even when the antecedent determination is
reviewable. Powerex, 551 U.S. at 236. Accordingly, when
we have found antecedent determinations to be separable
and reviewable, we do so without disturbing the remand
order. E.g., Sherwin v. Infinity Auto Ins. Co., 639 F. App’x.
466, 467 n.1 (9th Cir. 2016); Nebraska ex rel. Dep’t of Soc.
Servs. v. Bentson, 146 F.3d 676, 678 (9th Cir. 1998); Levin
Metals Corp. v. Parr-Richmond Terminal Co., 799 F.2d
1312, 1315 (9th Cir. 1986). The observation suggests a
formula for differentiating separable decisions from
unreviewable ones. An antecedent ruling that could be
reversed without disturbing the remand may, as in City of
Waco, be separable. However, if the ruling can only be
reversed by first undoing the remand, then it is not separable
and we may not review it. See Palmer v. City Nat’l Bank of
W. Va., 498 F.3d 236, 242–43 (4th Cir. 2007) (“A district
                    DEMARTINI V. DEMARTINI                            21

court decision that has a preclusive effect on the parties and
that is logically and factually separable from the remand
order is a decision that can be reviewed by this Court without
affecting the remand order.”); accord Fontenot, 718 F.3d
at 522.

    Because the trustees are not parties to the case currently
in federal court, it is impossible to imagine how we could
revisit their joinder without sticking our nose into state court
proceedings. As a result, Michael and Renate’s request to
review the amendment order ultimately “amounts to a
request for one of two impermissible outcomes: an advisory
opinion . . . or a reversal of the remand order.” Powerex,
551 U.S. at 236. Neither outcome is within our power; the
joinder decision is unreviewable by this court. 5

                                   C

     In holding that the joinder of a diversity-destroying party
is not separable from a § 1447(e) remand order and is
therefore unreviewable, we join the Fourth Circuit. See
Washington Suburban Sanitary Comm’n, 917 F.2d at 836
n.4.

   Two circuits, however, hold that an order amending a
complaint to add a diversity-destroying party is separable
from a remand order. Doleac ex rel. Doleac v. Michalson,
264 F.3d 470, 489 (5th Cir. 2001); Powers v. Southland


    5
      Michael and Renate request judicial notice of state-court filings in
proceedings on the remanded claim. Such filings are relevant only for
evaluating the appropriateness of the joinder, which this court may not
review. See Cachil Dehe Band of Wintun Indians of Colusa Indian Cmty.
v. Zinke, 889 F.3d 584, 594 n.5 (9th Cir. 2018). Consequently, the
motion to take judicial notice is DENIED.
22                  DEMARTINI V. DEMARTINI

Corp., 4 F.3d 223, 228 (3d Cir. 1993). 6 Respectfully, they
do not dissuade us from our holding.

                                    1

    The Fifth Circuit’s opinion in Doleac is notably
equivocal; it forthrightly acknowledged that an amendment
to join a diversity-destroying party “simply determined the
forum in which the claims would be decided and that both
parties would be subject to the same action. Therefore, it
does not appear analogous to issues found separable.”
Doleac, 264 F.3d at 487–88 (citation omitted). However, the
court believed itself bound by a precedent holding that an
amendment joining an immune party was separable from the
subsequent remand, even though that precedent failed to
consider the conclusiveness element of the City of Waco test.
Id. at 486, 489 (citing Tillman v. CSX Transp., Inc., 929 F.2d
1023 (5th Cir. 1991)).

     Doleac is also distinguishable because it concerns a
joinder preceding a remand pursuant to § 1447(c), while our
case (and the Fourth Circuit’s) concerns a remand under
§ 1447(e). As explained above, joinder and remand under
§ 1447(e) is a single exercise. Hence, even as it held that
joinder preceding a § 1447(c) remand was separable, the
Fifth Circuit opined that joinder pursuant to § 1447(e) was
very likely not separable from the remand. Doleac, 264 F.3d
at 488–89. The panel went so far as to suggest that the circuit
reconsider its holding en banc to bring the rule for § 1447(c)
in line with the rule for § 1447(e). Id. at 488, 489.

     6
      In neither case did the appellate court actually review the joinder,
each holding that the joinder order was not immediately appealable as
either a final decision or a collateral order. Doleac, 264 F.3d at 493;
Powers, 4 F.3d at 237.
                 DEMARTINI V. DEMARTINI                      23

                               2

     The Third Circuit’s holding in Powers hinged on a factor
not found here: the district court determined that the
amendment adding a diversity-destroying defendant would
relate back to the date that the complaint was originally filed.
As the court explained, the joinder at issue in the case
“consisted of two separate steps or decisions.” Powers,
4 F.3d at 230 n.8. The first such decision was whether the
amendment would relate back, a decision that was separable
because it “clearly affected significant substantive rights”—
i.e., the joined defendant would lose the benefit of the
expiration of the statute of limitations. Id. The second such
decision was whether joinder should be permitted. The court
conceded that without the relation-back decision, joinder
would have “no significant substantive effect on the rights
of the parties beyond determining the forum.” Id.

    We are not persuaded that either Doleac or Powers
constitute contrary authority. We are satisfied that the
joinder is not separable.

                              IV

    Although the district court’s amendment of the
complaint is not separable from the remand, severance of the
partnership dissolution claim may well be. But we need not
decide whether § 1447(d) bars our review of pre-remand
decisions to sever claims because Michael and Renate
expressly waived any objection on the merits to the district
court’s severance of the partnership dissolution claim.
24               DEMARTINI V. DEMARTINI

                              V

   Finally, Michael and Renate assert that this court should
construe their appeal as a petition for writ of mandamus over
which this court has jurisdiction under 28 U.S.C. § 1651(a).

    Congress undertook to exclude remand orders from our
review and anticipated that litigants might adopt an unusual
posture in order to raise their grievance before the courts of
appeals. For that reason, § 1447(d) states that “[a]n order
remanding a case to the State court from which it was
removed is not reviewable on appeal or otherwise.”
28 U.S.C. § 1447(d) (emphasis added). Review through a
writ of mandamus is one such alternative specifically
prohibited by § 1447(d). Gravitt v. Sw. Bell Tel. Co.,
430 U.S. 723, 723–24 (1977); see also In re Blatter, 241 F.
App’x 371, 373 (9th Cir. 2007). What § 1447(d) prohibits
on appeal, it also prohibits on petition for mandamus.
Mandamus is an “extraordinary remedy” and it is neither
warranted nor permissible here. Special Invs., 360 F.3d
at 993.

                             VI

    Michael and Renate cannot overcome the familiar bar to
appellate review of remand orders in cases removed from
state court.

     APPEAL DISMISSED.
