                 United States Court of Appeals
                            For the Eighth Circuit
                        ___________________________

                            Nos. 18-1824, 18-1856
                        ___________________________

 Kodiak Oil & Gas (USA) Inc., now known as Whiting Resources Corporation;
                          HRC Operating, LLC

                       lllllllllllllllllllllPlaintiffs - Appellees

                                           v.

   Jolene Burr; Ted Lone Fight; Georgianna Danks; Edward S. Danks; Mary
Seaworth, in her capacity as the Acting Chief Judge of the Fort Berthold District
                                      Court

                     lllllllllllllllllllllDefendants - Appellants

                             ------------------------------

                               EOG Resources, Inc.

                        lllllllllllllllllllllPlaintiff - Appellee

   Jolene Burr; Ted Lone Fight; Georgianna Danks; Edward S. Danks; Mary
Seaworth, in her capacity as the Acting Chief Judge of the Three Affiliated Tribes
 District Court of the Fort Berthold Indian Reservation; Charlene Knight, in her
  capacity as the Court Clerk/Consultant of the Three Affiliated Tribes District
                  Court of the Fort Berthold Indian Reservation;

                     lllllllllllllllllllllDefendants - Appellants
                                      ____________

                   Appeals from United States District Court
                       for the District of North Dakota
                                ____________
                              Submitted: March 14, 2019
                                Filed: August 5, 2019
                                    ____________

Before GRUENDER, BENTON, and GRASZ, Circuit Judges.
                         ____________

GRASZ, Circuit Judge.

       A dispute over the practice of flaring natural gas from oil wells fuels the legal
controversy in this case: the scope of Native American tribal court authority over non-
members. Several members of the MHA Nation sued numerous non-tribal oil and gas
companies in MHA tribal court. Those companies operate oil wells on lands within
the Fort Berthold Indian Reservation that have been allotted to individual tribe
members but are held in trust by the federal government. The tribe members alleged
the companies owed royalties from wastefully-flared gas. Some of these companies
unsuccessfully contested the tribal court’s jurisdiction over them in tribal court. Then
they initiated this action in federal court to enjoin the tribal court plaintiffs and tribal
court judicial officials. The district court1 issued a preliminary injunction, and the
tribal court plaintiffs and officials separately appealed. We affirm the injunction
because we conclude suits over oil and gas leases on allotted trust lands are governed
by federal law, not tribal law, and the tribal court lacks jurisdiction over the non-
member oil and gas companies.

                                     I. Background

    In February 2014, four individual members (the “tribal court plaintiffs”) of the
MHA (Mandan, Hidatsa, and Arikara) Nation (otherwise known as the Three

       1
       The Honorable Daniel L. Hovland, United States District Judge for the District
of North Dakota.

                                            -2-
Affiliated Tribes, residing on the Fort Berthold Indian Reservation) sued numerous
oil and gas companies in the Fort Berthold District Court of the MHA Nation. The
tribal court plaintiffs, on behalf of a proposed class of similarly situated plaintiffs,
alleged they owned mineral rights within the reservation and had entered into oil and
gas leases with the defendants. They alleged the defendants were operating wells on
the reservation that flared, or burned off, natural gas. Such flaring was improper, they
alleged, in part because “[t]echnology and services have been readily available to
capture, convert and market the natural gas without pipelines or electricity.” The
tribal court plaintiffs sought to recover royalties for the flared natural gas.

       The form lease executed by the tribal court plaintiffs and the companies was
issued by the U.S. Department of the Interior, Bureau of Indian Affairs (“BIA”), and
required approval by the BIA. The tribal court plaintiffs relied on a provision of the
lease in which the lessee agreed: “To exercise reasonable diligence in drilling and
operating wells for oil and gas . . . having due regard for the prevention of waste of
oil or gas developed on the land . . . .”

      The tribal court defendants moved to dismiss, arguing, among other things, that
the court lacked jurisdiction over them. Fort Berthold Special District Court Judge
Terry L. Pechota denied the motion. Judge Pechota concluded the tribe could
exercise jurisdiction over the defendants because they voluntarily entered into
contractual relationships with tribe members. The defendants appealed to the MHA
Nation Supreme Court, which asserted that “[f]rom time immemorial, the governing
bodies of the MHA Nation exercised inherent sovereignty over all persons who
entered the Nation’s territory.” The court commented that Montana v. United States,
450 U.S. 544 (1981), was “[t]he most infamous modern manifestation of the” U.S.
Supreme Court’s “long legacy of limiting various aspects of tribal sovereignty.” The
MHA Nation Supreme Court then concluded Montana — which generally prohibits
the exercise of tribal court jurisdiction over non-members — either did not apply or
the case fell under an exception allowing tribal regulation of “the activities of

                                          -3-
nonmembers who enter consensual relationships with the tribe or its members,
through commercial dealing, contracts, leases, or other arrangements.” Montana, 450
U.S. at 565.

      Kodiak Oil & Gas, Inc. and EOG Resources, Inc., two of the tribal court
defendants, separately filed suit in federal court against the tribal court plaintiffs and
the acting chief judge of the Fort Berthold District Court. EOG Resources also
included the court clerk of the Fort Berthold District Court as a defendant. HRC
Operating, LLC, later intervened in Kodiak’s case. Kodiak, EOG, and HRC
(hereinafter “the oil and gas companies”) argued the tribal court lacked jurisdiction
over them and sought declaratory and injunctive relief. The two cases were
eventually consolidated. The district court denied the tribal court judge’s motion to
dismiss and granted the oil and gas companies’ motion for a preliminary injunction.
The Forth Berthold chief district judge and clerk of court (collectively “the tribal
court officials”) and the tribal court plaintiffs separately appealed.

                                   II. Analysis
                           A. Tribal Sovereign Immunity

      The tribal court officials argue this suit is barred by tribal sovereign immunity.
The district court correctly rejected this argument.

       Indian tribes are “quasi-sovereign nations.” Santa Clara Pueblo v. Martinez,
436 U.S. 49, 71 (1978). Tribes “exercise ‘inherent sovereign authority’” and “remain
‘separate sovereigns pre-existing the Constitution.’” Michigan v. Bay Mills Indian
Cmty., 572 U.S. 782, 788 (2014) (first quoting Oklahoma Tax Comm’n v. Citizen
Band Potawatomi Indian Tribe of Okla., 498 U.S. 505, 509 (1991); then quoting
Santa Clara Pueblo, 436 U.S. at 56). Yet as “domestic dependent nations,” tribes
“are subject to plenary control by Congress.” Id. (quoting Citizen Band Potawatomi,
498 U.S. at 509). By virtue of their limited sovereignty, tribes possess (subject to

                                           -4-
congressional limitation or expansion) the “common-law immunity from suit
traditionally enjoyed by sovereign powers.” Id. (quoting Santa Clara Pueblo, 436
U.S. at 58). This immunity extends to tribal officials who act within the scope of the
tribe’s lawful authority. Baker Elec. Co-op., Inc. v. Chaske, 28 F.3d 1466, 1471 (8th
Cir. 1994).

        In Ex parte Young, 209 U.S. 123 (1908), the Supreme Court recognized
sovereign immunity does not bar “certain suits seeking declaratory and injunctive
relief against state officers in their individual capacities” based on ongoing violations
of federal law. Idaho v. Coeur d’Alene Tribe of Idaho, 521 U.S. 261, 269 (1997).
The Ex parte Young doctrine rests on the premise “that when a federal court
commands a state official to do nothing more than refrain from violating federal law,
he is not the State for sovereign-immunity purposes.” Virginia Office for Prot. &
Advocacy v. Stewart, 563 U.S. 247, 255 (2011). The Supreme Court has extended the
Ex parte Young doctrine from state officials to tribal officials, holding “tribal
immunity does not bar such a suit for injunctive relief against individuals, including
tribal officers, responsible for unlawful conduct.” Bay Mills, 572 U.S. at 796; see
also N. States Power Co. v. Prairie Island Mdewakanton Sioux Indian Cmty., 991
F.2d 458, 460 (8th Cir. 1993).

       Here, the oil and gas companies seek only declaratory and injunctive relief, not
damages. They also contend the tribal court officials exceeded the scope of their
lawful authority. Thus, this case falls squarely within the Ex parte Young doctrine
and is not barred by tribal sovereign immunity.

      To avoid this obvious conclusion, the tribal court officials argue the oil and gas
companies “never claimed, let alone showed, that [they] did anything regarding the
underlying tribal court case.” In other words, the oil and gas companies should have
named the presiding judge as a defendant, not just the chief judge and clerk of court.
This raises the question of whether the tribal court officials’ supervisory and

                                          -5-
administrative authority is a sufficient connection to the improper exercise of
jurisdiction to be subjected to suit for declaratory and injunctive relief. In Ex parte
Young, the Supreme Court held that when seeking to enjoin the enforcement of an
unconstitutional state statute, the state officer defendant “must have some connection
with the enforcement of the act, or else it is merely making him a party as a
representative of the state, and thereby attempting to make the state a party.” 209
U.S. at 157; see also Balogh v. Lombardi, 816 F.3d 536, 546 (8th Cir. 2016) (state
officials with authority to implement statute “in an administrative or ministerial
sense” generally do not have sufficient connection to the statute’s enforcement);
Church v. Missouri, 913 F.3d 736, 750 (8th Cir. 2019) (“Like in Balogh, appointing
members of the [Missouri State Public Defender] Commission is an administrative
act. It does not give the governor some connection to the State’s Sixth Amendment
obligation [to provide indigent defendants with adequate counsel].” (internal citation
omitted)). So too, when seeking to enjoin an improper exercise of tribal court
jurisdiction, the tribal official “must have some connection with the” exercise of
jurisdiction. Ex parte Young, 209 U.S. at 157. But where a tribal official is giving
effect to the unlawful exercise of jurisdiction “in a manner that allegedly injures a
plaintiff and violates his constitutional rights, an action” for injunctive or declaratory
relief is available against the tribal official. McDaniel v. Precythe, 897 F.3d 946, 952
(8th Cir. 2018). Because the chief district court judge and clerk of court have
supervisory and administrative duties related to the tribal court case, we conclude
they have a sufficient connection to the improper exercise of jurisdiction and are
properly subject to suit for declaratory and injunctive relief.

        Next, the tribal court officials argue that no jurisdiction has been exercised thus
far in the tribal court litigation over the merits of the controversy. All the tribal court
has done is determine whether it has jurisdiction. And every court has the jurisdiction
to determine whether it has jurisdiction over a case. See, e.g., In re Brewer, 863 F.3d
861, 868 (D.C. Cir. 2017) (“[Federal courts] have jurisdiction to determine [thei]r
own jurisdiction.”); Carlson v. Allianz Versicherungs-Aktiengesellschaft, 287 Neb.

                                           -6-
628, 638 (2014) (“It is fundamental that a court has the power to determine whether
it has jurisdiction over the matter before it.”). While this argument is framed as a
sovereign immunity issue, in substance it is an argument about ripeness — an
argument that the case is not ripe because the tribal court has not yet exercised
jurisdiction over the merits of the controversy. Assuming the tribal court had
jurisdiction to determine its own jurisdiction, the oil and gas companies’ case is still
ripe because the tribal court’s exercise of jurisdiction over the merits of the case was
“sufficiently imminent.” Susan B. Anthony List v. Driehaus, 573 U.S. 149, 159
(2014) (discussing pre-enforcement challenges). Indeed, it would be puzzling for the
tribal court to determine it had jurisdiction over the case only to refrain from
exercising that jurisdiction.2

       We conclude the oil and gas companies’ claims for declaratory and injunctive
relief against the tribal court officials are not barred by tribal sovereign immunity.

                             B. Preliminary Injunction

      The district court did not abuse its discretion in granting the preliminary
injunction because the oil and gas companies are likely to prevail on the merits.

       “Our review of a preliminary injunction is layered: fact findings are reviewed
for clear error, legal conclusions are reviewed de novo, and the ‘ultimate decision to

      2
        While the MHA Nation Supreme Court concluded the tribal court could
exercise jurisdiction over the oil and gas companies, it disagreed with the tribal
district court that the tribal court plaintiffs were not required to exhaust their
administrative remedies with the U.S. Department of Interior’s Bureau of Land
Management and remanded for further proceedings. Nevertheless, we believe this
case still presents a live case or controversy for us to decide. The tribal district court
case remains pending and has not been dismissed. Even after the remand, the tribal
court plaintiffs sought to certify their proposed class of plaintiffs and have asserted
to this court that they are excused from exhaustion because doing so would be futile.

                                           -7-
grant the injunction’ is reviewed for abuse of discretion.” Comprehensive Health of
Planned Parenthood Great Plains v. Hawley, 903 F.3d 750, 754 (8th Cir. 2018)
(quoting McKinney ex rel. NLRB v. S. Bakeries, LLC, 786 F.3d 1119, 1122 (8th Cir.
2015)). The factors for evaluating whether a preliminary injunction should be issued
are: “(1) the threat of irreparable harm to the movant; (2) the state of the balance
between this harm and the injury that granting the injunction will inflict on other
parties litigant; (3) the probability that movant will succeed on the merits; and (4) the
public interest.” Dataphase Sys., Inc. v. C L Sys., Inc., 640 F.2d 109, 113 (8th Cir.
1981) (en banc). “While ‘no single factor is determinative,’ the probability of success
factor is the most significant.” Home Instead, Inc. v. Florance, 721 F.3d 494, 497
(8th Cir. 2013) (citations omitted) (quoting Dataphase, 640 F.2d at 113).

                             1. Tribal Court Exhaustion

        The district court correctly concluded the oil and gas companies exhausted
their tribal court remedies3 by moving to dismiss the case for lack of jurisdiction and
appealing the issue to the MHA Nation Supreme Court. Before challenging an
exercise of tribal court jurisdiction in federal court, parties must generally exhaust
their challenge in tribal court. See Iowa Mut. Ins. Co. v. LaPlante, 480 U.S. 9, 16–19
(1987); Nat’l Farmers Union Ins. Cos. v. Crow Tribe of Indians, 471 U.S. 845,
855–57 (1985). But this requirement is not jurisdictional, it is a prudential rule based
in “[r]espect for tribal self-government,” allowing “the tribal court a ‘full opportunity
to determine its own jurisdiction.’” Strate v. A-1 Contractors, 520 U.S. 438, 451
(1997) (quoting Iowa Mut. Ins., 480 U.S. at 16). And exhaustion is not required


      3
        One of the oil and gas companies argues we lack jurisdiction to review the
district court’s determination of exhaustion of tribal remedies because the district
court addressed that issue in denying the tribal court officials’ motion to dismiss. We
review the issue not because we have jurisdiction to review the denial of the motion
to dismiss but because it bears on the oil and gas companies’ likelihood of success on
the merits.

                                          -8-
where it is “plain” the tribal court lacks jurisdiction or where exhaustion “would serve
no purpose other than delay.” Id. at 459 n.14; see also Belcourt Pub. Sch. Dist. v.
Davis, 786 F.3d 653, 656 n.2 (8th Cir. 2015).

       The tribal court officials and tribal court plaintiffs argue that even though the
oil and gas companies pursued their jurisdictional challenge to the MHA Nation
Supreme Court, they still did not adequately exhaust their remedies because they only
raised a facial challenge to tribal court jurisdiction. “Exhaustion of [tribal] court
remedies requires development of the factual record in the Tribe’s Court,” they claim,
pointing to this court’s decision in Duncan Energy Co. v. Three Affiliated Tribes of
Ft. Berthold Reservation, 27 F.3d 1294 (8th Cir. 1994). This court’s opinion in
Duncan Energy does not require the development of a factual record in every case
(nor would such a requirement likely be consistent with subsequent Supreme Court
precedent). See id. at 1299–1301. Rather, in Duncan Energy we said “the
requirement of tribal exhaustion contemplates the development of a factual record
that will serve the ‘orderly administration of justice in the federal court.’” Id. at 1300
(quoting Nat’l Farmers, 471 U.S. at 856). While the development of a factual record
may generally be required where a challenge to tribal court jurisdiction turns on
disputed factual questions, factual development is generally not required for facial
challenges to jurisdiction. Requiring the development of a factual record where the
jurisdictional challenge does not turn on issues of fact would not serve the “orderly
administration of justice,” Nat’l Farmers, 471 U.S. at 856, and “would serve no
purpose other than delay,” Strate, 520 U.S. at 459 n.14.

                             2. Tribal Court Jurisdiction

       The district court correctly concluded the tribal court lacked jurisdiction over
the oil and gas companies.




                                           -9-
       The Supreme Court in Montana said that while Indian tribes possess “attributes
of sovereignty over both their members and their territory,” they “have lost many of
the attributes of sovereignty” through “their original incorporation into the United
States as well as through specific treaties and statutes.” 450 U.S. at 563 (quoting
United States v. Wheeler, 435 U.S. 313, 326 (1978)). Thus, “exercise of tribal power
beyond what is necessary to protect tribal self-government or to control internal
relations is inconsistent with the dependent status of the tribes, and so cannot survive
without express congressional delegation.” Id. at 564.

        We conclude the tribal court lacked jurisdiction over the oil and gas companies
for two reasons. First, as to non-members, tribal courts are not courts of general
jurisdiction and oil and gas leases on allotted trust lands are governed by federal law,
not tribal law. Second, neither of the two exceptions in Montana to the general rule
that tribes may not regulate the activities of non-members applies here.

            a. Tribal Court Jurisdiction over Federal Causes of Action

        The oil and gas companies argue the tribal court lacks jurisdiction because: (a)
tribal court adjudicatory jurisdiction is, in the absence of congressional authorization,
limited to tribal law, and (b) the suit at issue here is a federal cause of action. The
tribal court officials and tribal court plaintiffs counter that the first premise of this
argument rests on an incorrect reading of Nevada v. Hicks, 533 U.S. 353 (2001),
which they assert “must be viewed narrowly,” and that tribal courts may hear federal
causes of action in some circumstances. We agree with the oil and gas companies and
address their two contentions in turn.

       In Hicks, the Supreme Court held that tribal courts are not courts of general
jurisdiction — unlike state courts that “can adjudicate cases invoking federal
statutes . . . absent congressional specification to the contrary.” Hicks, 533 U.S. at
366. The Court held that because “no provision in federal law provides for

                                          -10-
tribal-court jurisdiction over [42 U.S.C.] § 1983 actions . . . tribal courts cannot
entertain § 1983 suits.” Hicks, 533 U.S. at 368–69. The Supreme Court’s holding in
Hicks brought to the fore an ambiguity in the Court’s prior holding that “[a]s to
nonmembers . . . a tribe’s adjudicative jurisdiction does not exceed its legislative
jurisdiction.” Strate, 520 U.S. at 453. The ambiguity is whether tribal court
adjudicative jurisdiction is limited to cases arising from conduct that could be
permissibly regulated by tribal law, as determined by Montana and its two exceptions,
or whether tribal court adjudicative jurisdiction is limited to cases arising from
conduct that has been regulated by tribal law, i.e., limited to causes of action arising
under tribal law.

       We conclude the better reading of Hicks is that, at least where non-members
are concerned, tribal courts’ adjudicative authority is limited (absent congressional
authorization) to cases arising under tribal law.4 First, the Supreme Court did not just
reject tribal court adjudicative jurisdiction over § 1983 actions based on conduct
falling outside the Montana exceptions. See Hicks, 533 U.S. at 366–69. Rather, it
concluded tribal courts lack jurisdiction to hear any § 1983 claims. See id. Second,
the Court’s other reasoning in Hicks supports this reading. The Court emphasized the
lack of congressional authorization for tribal courts to hear § 1983 claims and that
allowing tribal court jurisdiction would deny defendants access to a federal forum
through removal, as defendants have in a state court action. See id. Here too, there
is no congressional authorization for tribal courts to hear suits involving oil and gas
leases of allotted Indian trust land. And the absence of a federal forum is a concern
that applies not just to § 1983 actions, but any time a federal claim is heard in tribal
court. Finally, this reading is consistent with the Court’s broad principle that
“[w]here nonmembers are concerned, the ‘exercise of tribal power beyond what is


      4
        Even if tribal courts’ authority were not limited to tribal law, the tribal court
lacked authority over the oil and gas companies here because its exercise of
jurisdiction did not fit into either of the Montana exceptions, as discussed below.

                                          -11-
necessary to protect tribal self-government or to control internal relations is
inconsistent with the dependent status of the tribes, and so cannot survive without
express congressional delegation.’” Id. at 359 (emphasis omitted) (quoting Montana,
450 U.S. at 564). Given the Supreme Court’s reasoning in Hicks, we conclude the
better reading is that tribal courts lack jurisdiction to adjudicate federal causes of
action absent congressional authorization.5

      We also agree with the oil and gas companies that the tribal court plaintiffs’
claim for relief is based on federal law.

      Under the General Allotment Act of 1887, 24 Stat. 388, many Indian lands
were divided and allotted to individual Indians but were held in trust for their benefit
by the federal government. See Upper Skagit Indian Tribe v. Lundgren, 138 S. Ct.
1649, 1652–53 (2018); 25 U.S.C. §§ 334–358. In 1909, Congress passed an act
authorizing the leasing of allotted lands for “mining purposes,” including the
extraction of oil and gas. 25 U.S.C. § 396; see also 25 C.F.R. § 212.3. But such
leases must be approved by the Secretary of the Interior, who “is authorized to
perform any and all acts and make such rules and regulations as may be necessary.”
25 U.S.C. § 396. Leases are required to “be on forms, prescribed by the Secretary [of


      5
          This conclusion is consistent with El Paso Nat. Gas Co. v. Neztsosie, 526 U.S.
473 (1999), which affirmed the denial of an injunction against the exercise of tribal
court jurisdiction over claims under the Price-Anderson Act (Atomic Energy
Damages Act). The Supreme Court in Hicks distinguished El Paso by explaining that
in El Paso “the claims were not initially federal claims, but [tribal law] tort claims
that the Price-Anderson Act provided [in 42 U.S.C. § 2014(hh)] ‘shall be deemed to
be . . . action[s] arising under’ 42 U.S.C. § 2210.” Hicks, 533 U.S. at 368 (alterations
in original). Because the claims at issue in El Paso were tribal law claims (governed
by tribal law to the extent not inconsistent with the Price-Anderson Act, § 2014(hh))
“deemed” to be federal claims, El Paso does not stand for the broad proposition that
tribal courts have jurisdiction to entertain federal causes of action absent
congressional authorization.

                                         -12-
the Interior],” which may only be changed with the Secretary’s approval. 25 C.F.R.
§ 211.57; see also id. § 212.57. The lease included in the record here is a form lease
and requires the lessee “[t]o abide by and conform to any and all regulations of the
Secretary of the Interior now or hereafter in force relative to such leases.”

       Federal regulations control nearly every aspect of the leasing process, such as
how leases are awarded, id. § 212.20, the size of land that may be included in a single
lease, id. §§ 211.25, 212.25, the duration of leases, id. §§ 211.27, 212.27, the spacing
of oil wells, id. § 212.28(h), the rates of royalties for oil and gas leases, id. § 212.41,
the manner of payment, id. §§ 211.40, 212.40, and more. And the Bureau of Land
Management extensively regulates and monitors oil and gas drilling operations.
See 43 C.F.R. pt. 3160; see also 25 C.F.R. § 212.4.

       Federal law also controls the entire process of royalty payments under the
Federal Oil and Gas Royalty Management Act. See 30 U.S.C. §§ 1701–1759.
Royalties are paid to the Department of Interior’s Office of Natural Resources
Revenue, which in turn disburses the royalties to the allottees, see id.; 30 C.F.R.
§§ 1218.100–1218.105, 1219.103, and federal law provides for penalties for failure
to pay royalties due under a lease, see 30 U.S.C. § 1719. Relevant to this case, the
Department of the Interior has issued a notice specifically addressing the issue of
“Royalty or Compensation for Oil and Gas Lost” by flaring. U.S. Dep’t of the
Interior Geological Survey Conservation Div., NTL-4A (“Flaring Notice”) (1980).
In sum, “[t]he total of these regulations is comprehensive, giving wide powers to [the
Department of the] Interior as to all aspects of the leasing arrangement.” Pawnee v.
United States, 830 F.2d 187, 190 (Fed. Cir. 1987); see also Jicarilla Apache Nation
v. U.S. Dep’t of the Interior, 892 F. Supp. 2d 285, 292 (D.D.C. 2012) (“[T]he
royalties program for federal and Indian oil and gas leases is ‘a complex and highly
technical regulatory program’ which requires ‘significant expertise’ and the ‘exercise
of judgment grounded in policy concerns’ by the Department [of the Interior].”
(quoting Thomas Jefferson Univ. v. Shalala, 512 U.S. 504, 512 (1994))).

                                           -13-
       Unlike “routine contracts” that are “governed by general common law
principles of contract,” oil and gas leases on federally-held Indian trust land are
governed by federal law. See Comstock Oil & Gas Inc. v. Alabama & Coushatta
Indian Tribes of Tex., 261 F.3d 567, 573–75 (5th Cir. 2001); see also Gaming World
Int’l, Ltd. v. White Earth Band of Chippewa Indians, 317 F.3d 840, 847 (8th Cir.
2003) (“In terms of [federal question] jurisdiction there is a significant distinction
between ordinary contract disputes involving Indian tribes, and those raising issues
in an area of extensive federal regulation.” (citation omitted)); Naegele Outdoor
Advert. Co. v. Acting Sacramento Area Director, Bureau of Indian Affairs, 24 IBIA
169, 177 (1993) (Interior Board of Indian Appeals) (“[T]he construction of Federal
contracts, including contracts approved on behalf of an Indian or Indian tribe by the
Secretary of the Interior in his fiduciary capacity, is a question of Federal law.”).

       Because the tribal courts’ adjudicative authority is limited to cases arising
under tribal law and the case at issue here arises under federal law, we conclude the
tribal court lacked jurisdiction.

       Finally, we note that if the tribal court plaintiffs were attempting to proceed
under tribal contract law, such tribal law would be preempted. The tribal court
officials and tribal court plaintiffs primarily argue it does not matter whether the tribal
court plaintiffs’ cause of action arises under federal or tribal law. But there is some
suggestion in their briefs that it is based in the “MHA [Nation] common law” of
contracts. To the extent it is based on tribal contract law, the enforcement of such
tribal law would not only be impermissible under Montana and its progeny, as
discussed below, but would also be preempted. See Murphy v. Nat’l Collegiate
Athletic Ass’n, 138 S. Ct. 1461, 1480 (2018) (discussing field preemption); Arizona
v. United States, 567 U.S. 387, 401 (2012) (same). Federal law and regulation
exhaustively occupies the field of oil and gas leases on allotted Indian lands. And
more specifically, federal law exhaustively addresses the collection and distribution
of royalties on such leases and the practice of flaring natural gas as it relates to

                                           -14-
royalty payments. See 30 U.S.C. §§ 1701–1759; 30 C.F.R. §§ 1281.100–1218.105,
1219.103; Flaring Notice. Congress has left no room for tribal law to supplement this
comprehensive regulatory scheme.

                   b. Tribal Court Jurisdiction over Non-Indians

       Aside from the tribal court’s lack of jurisdiction to hear federal causes of
action, the tribal court lacked jurisdiction because the subject of the dispute was
outside its legislative jurisdiction. The scope of tribes’ legislative jurisdiction
vis-à-vis non-members is determined by the Supreme Court’s Montana opinion and
its progeny.

       The general rule is Indian “tribes do not, as a general matter, possess authority
over non-Indians who come within their borders.” Plains Commerce Bank v. Long
Family Land & Cattle Co., 554 U.S. 316, 328 (2008); see also Montana, 450 U.S. at
565 (“[T]he inherent sovereign powers of an Indian tribe do not extend to the
activities of nonmembers of the tribe.”). Given their “diminished status as
sovereigns,” the Supreme Court has said “the Indian tribes have lost any ‘right of
governing every person within their limits except themselves.’” Montana, 450 U.S.
at 565 (quoting Oliphant v. Suquamish Indian Tribe, 435 U.S. 191, 209 (1978)).

       The Supreme Court in Montana recognized two exceptions where tribes may
exercise civil jurisdiction over non-members: (1) “A tribe may regulate, through
taxation, licensing, or other means, the activities of nonmembers who enter
consensual relationships with the tribe or its members, through commercial dealing,
contracts, leases, or other arrangements,” and (2) “A tribe may also retain inherent
power to exercise civil authority over the conduct of non-Indians on fee lands within
its reservation when that conduct threatens or has some direct effect on the political
integrity, the economic security, or the health or welfare of the tribe.” Id. at 565–66.



                                         -15-
      But the Supreme Court has said “[t]hese exceptions are ‘limited’ ones and
cannot be construed in a manner that would ‘swallow the rule’ or ‘severely shrink’
it.” Plains Commerce Bank, 554 U.S. at 330 (citations omitted) (first quoting
Atkinson Trading Co. v. Shirley, 532 U.S. 645, 647, 655 (2001); then quoting Strate,
520 U.S. at 458). The Montana exceptions apply only to the extent they are
“necessary to protect tribal self-government or to control internal relations.” Hicks,
533 U.S. at 359 (emphasis omitted); see also Plains Commerce Bank, 554 U.S. at
332; Montana, 450 U.S. at 564.

        The first Montana exception does not apply here. The oil and gas companies’
leases are consensual relationships with tribal members, but the entire relationship is
mediated by the federal government. A consensual relationship alone is not enough.
Even where there is a consensual relationship with the tribe or its members, the tribe
may regulate non-member activities only where the regulation “stem[s] from the
tribe’s inherent sovereign authority to set conditions on entry, preserve tribal
self-government, or control internal relations.” Plains Commerce Bank, 554 U.S. at
336. The complete federal control of oil and gas leases on allotted lands — and the
corresponding lack of any role for tribal law or tribal government in that
process — undermines any notion that tribal regulation in this area is necessary for
tribal self-government. And the relevant conduct by the oil and gas companies is the
failure to pay the disputed royalties, an activity that takes place between the
non-member companies and the federal government (which in turn calculates and
makes payments to the allottees). Tribal regulation of these payments is not
necessary for tribal self-government or controlling internal relations. The fact the
allotted land at issue here is held in trust for individual tribe members does not
change our conclusion. See Hicks, 533 U.S. at 360 (“The ownership status of
land . . . is only one factor to consider in determining whether regulation of the
activities of nonmembers is ‘necessary to protect tribal self-government or to control
internal relations.’”).



                                         -16-
        Nor does the second Montana exception apply. Again, this second exception
“grants Indian tribes nothing ‘beyond what is necessary to protect tribal
self-government or to control internal relations.’” Atkinson Trading, 532 U.S. at
658–59 (quoting Strate, 520 U.S. at 459). This dispute over the payment of royalties
does not involve conduct that “threatens or has some direct effect on the political
integrity, the economic security, or the health or welfare of the tribe.” Montana, 450
U.S. at 566. The oil and gas companies’ failure to pay the disputed royalties related
to the flaring does not “‘imperil the subsistence’ of the tribal community,” as is
required to satisfy the second exception. Plains Commerce Bank, 554 U.S. at 341
(quoting Montana, 450 U.S. at 566). Importantly, while the tribal court plaintiffs
initially relied in part on an MHA Nation resolution that purported to regulate the
practice of flaring on the reservation, they subsequently abandoned that reliance in
favor of a straightforward contract-based approach. Tribal court enforcement of tribal
laws relating to public health and safety or environmental protection may sometimes
fall within the second Montana exception, but the dispute here, according to the tribal
court plaintiffs, “is a contract dispute, pure and simple.” Adjudicating disputes over
the payment of royalties under a system for payment of such royalties wholly
controlled by the federal government under federal law is not “necessary to protect
tribal self-government or to control internal relations.’” Atkinson Trading, 532 U.S.
at 658–59 (quoting Strate, 520 U.S. at 459).

      Based on the foregoing, we conclude the oil and gas companies have shown a
strong likelihood of success on the merits.

                      3. Other Preliminary Injunction Factors

      Having concluded the oil and gas companies are likely to prevail on the merits,
we turn to the remaining preliminary injunction factors. See Dataphase, 640 F.2d at
113. While the threat of irreparable injury to the oil and gas companies is uncertain,
see DISH Network Serv. L.L.C. v. Laducer, 725 F.3d 877, 882 (8th Cir. 2013), we

                                         -17-
conclude the balance of the factors favors them. Without the injunction, the oil and
gas companies would be forced to expend the time and cost associated with
continuing litigation in a tribal court that lacks jurisdiction over them, whereas the
only possible injury to the tribal court plaintiffs and tribal court officials from the
injunction is delay. The balance of these factors, along with the oil and gas
companies’ strong likelihood of success on the merits, show the district court did not
abuse its discretion by granting the preliminary injunction.

                                   III. Conclusion

      For the reasons set forth herein, we affirm the district court’s grant of a
preliminary injunction.6
                      ______________________________




      6
       The tribal court officials object to the district court’s failure to rule on their
motion to dismiss on the basis of the failure to join the MHA Nation as a party. See
Fed. R. Civ. P. 19. Because the district court has not yet ruled on this issue, we lack
appellate jurisdiction to review its failure to decide the issue.

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