Navajo Nation v. Usdoi

FOR PUBLICATION

UNITED STATES COURT OF APPEALS
FOR THE NINTH CIRCUIT

NAVAJO NATION, No. 19-17088
Plaintiff-Appellant,
D.C. No.
v. 3:03-cv-00507-
GMS
U.S. DEPARTMENT OF THE INTERIOR;
DEB HAALAND, Secretary of the
Interior; UNITED STATES BUREAU OF ORDER AND
RECLAMATION; BUREAU OF INDIAN AMENDED
AFFAIRS, OPINION
Defendants-Appellees,

STATE OF ARIZONA; CENTRAL
ARIZONA WATER CONSERVATION
DISTRICT; ARIZONA POWER
AUTHORITY; SALT RIVER PROJECT
AGRICULTURAL IMPROVEMENT AND
POWER DISTRICT; SALT RIVER
VALLEY WATER USERS’
ASSOCIATION; IMPERIAL IRRIGATION
DISTRICT; METROPOLITAN WATER
DISTRICT OF SOUTHERN CALIFORNIA;
COACHELLA VALLEY WATER
DISTRICT; STATE OF NEVADA;
COLORADO RIVER COMMISSION OF
NEVADA; SOUTHERN NEVADA
WATER AUTHORITY; STATE OF
COLORADO,
Intervenor-Defendants-Appellees.
2 NAVAJO NATION V. USDOI

Appeal from the United States District Court
for the District of Arizona
G. Murray Snow, Chief District Judge, Presiding

Argued and Submitted October 16, 2020
Pasadena, California

Filed April 28, 2021
Amended February 17, 2022

Before: Ronald M. Gould, Marsha S. Berzon, and
Kenneth K. Lee, Circuit Judges.

Order;
Opinion by Judge Gould;
Concurrence by Judge Lee

SUMMARY *

Water Rights / Tribal Matters

The panel reversed the district court’s dismissal, based
on lack of jurisdiction, of Navajo Nation’s breach of trust
claim alleging that Federal Appellees failed to consider the
Nation’s as-yet-undetermined water rights in managing the
Colorado River.

The district court held that any attempt by the Nation to
amend its complaint was futile because the district court
lacked jurisdiction to decide the breach of trust claim due to
*
This summary constitutes no part of the opinion of the court. It
has been prepared by court staff for the convenience of the reader.
 NAVAJO NATION V. USDOI 3

the Supreme Court reserving jurisdiction over allocation of
rights to the Colorado River in Arizona v. California
(Arizona I), 373 U.S. 546 (1963) (opinion); accord Arizona
v. California (1964 Decree), 376 U.S. 340, 353 (1964)
(decree).

The panel held that the district court erred in dismissing
the complaint because the amendment was not futile.
Although the Supreme Court retained original jurisdiction
over water rights claims to the Colorado River in Arizona I,
the Nation’s complaint did not seek a judicial quantification
of rights to the River, and therefore, the panel need not
decide whether the Supreme Court’s retained jurisdiction
was exclusive. The panel concluded it had jurisdiction to
consider the Nation’s claim, and the district court erred in
holding otherwise.

The panel held, contrary to the Intervenors’ arguments
on appeal, that the Nation’s claim was not barred by res
judicata, despite the federal government’s representation of
the Nation in Arizona I. The panel held that the Nation, here,
asserted a different claim than the water rights claim the
federal government could have asserted on the Nation’s
behalf in Arizona I. The federal government’s fiduciary duty
to the Nation was never at issue in Arizona I, and no final
judgment was ever entered on the merits of any question
concerning that subject.

Finally, the panel held that the district court erred in
denying the Nation’s motion to amend and in dismissing the
Nation’s complaint, because the complaint properly stated a
breach of trust claim premised on the Nation’s treaties with
the United States and the Nation’s federally reserved Winters
rights, especially when considered along with the Federal
Appellees’ pervasive control over the Colorado River. At
4 NAVAJO NATION V. USDOI

this early stage of the litigation, the panel declined to address
whether the Nation’s Winters rights included rights to the
mainstream of the Colorado River or to any other specific
water resources. The panel remanded to the district court
with instructions to permit the Nation to amend its
complaint.

Judge Lee concurred. He wrote separately to emphasize
that the Nation’s proposed injunctive relief should not and
did not implicate the Supreme Court’s retained jurisdiction
in the 1964 Decree.

COUNSEL

M. Kathryn Hoover (argued), Sacks Tierney P.A.,
Scottsdale, Arizona; Stanley M. Pollack, Navajo Nation
Department of Justice, Window Rock, Arizona; Alice E.
Walker and Gregg H. DeBie, Meyer Walker Condon &
Walker P.C., Boulder, Colorado; for Plaintiff-Appellant.

John L. Smeltzer (argued), Mary Gabrielle Sprague, and
Thomas Snodgrass, Attorneys; Todd Kim, Assistant
Attorney General; Environment and Natural Resources
Division, United States Department of Justice, Washington,
D.C.; Robert Snow and Sarah Foley, Attorneys, Solicitor’s
Office, United States Department of the Interior,
Washington, D.C.; for Defendants-Appellees.

Rita P. Maguire (argued), Rita P. Maguire PLLC, Phoenix,
Arizona; Steven B. Abbott, Redwine and Sherrill LLP,
Riverside, California; Kenneth C. Slowinski and Jennifer
Heim, Arizona Department of Water Resources, Phoenix,
Arizona; Marcia Scully and Catherine M. Stites,
Metropolitan Water District of Southern California, Los
 NAVAJO NATION V. USDOI 5

Angeles, California; Charles T. DuMars, Law & Resource
Planning Associates P.C., Albuquerque, New Mexico; John
B. Weldon Jr. and Lisa M. McKnight, Salmon Lewis &
Weldon P.L.C., Phoenix, Arizona; Stuart L. Somach and
Robert B. Hoffman, Somach Simmons & Dunn APC,
Sacramento, California; Jay M. Johnson, Central Arizona
Water Conservation District, Phoenix, Arizona; Aaron Ford,
Attorney General; Christine Guerci-Nyhus, Special Counsel
to the Colorado River Commission of Nevada; State of
Nevada and Colorado River Commission of Nevada, Las
Vegas, Nevada; Gregory J. Walch, General Counsel,
Southern Nevada Water Authority, Las Vegas, Nevada;
Lauren J. Caster and Bradley J. Pew, Fennemore Craig P.C.,
Phoenix, Arizona; Philip J Weiser, Attorney General; A.
Lain Leoniak, First Assistant Attorney General; Office of the
Attorney General, Denver, Colorado; for Intervenor-
Defendants-Appellees.

Monte Tyler Mills, Associate Professor and Director,
Margery Hunter Brown Indian Law Clinic, Alexander
Blewett III School of Law, University of Montana,
Missoula, Montana, for Amici Curiae Law Professors.

David L. Gover, Joe M. Tenorio, and Matthew Campbell,
Native American Rights Fund, Boulder, Colorado; Daniel D.
Lewerenz, Native American Rights Fund, Washington,
D.C.; Derrick Beetso, National Congress of American
Indians, Washington, D.C.; for Amicus Curiae NCAI Fund.
6 NAVAJO NATION V. USDOI

ORDER

The opinion in the above-captioned matter filed on April
28, 2021, and published at 996 F.3d 623, is amended as
follows:

At 996 F.3d at 629, delete

At 996 F.3d at 641, replace with

The panel has voted to deny Intervenor-Appellees’
petition for rehearing en banc (Dkt. 61), and to deny
Defendant-Appellees’ petition for rehearing en banc
(Dkt. 62). The full court has been advised of the petitions
for rehearing en banc and no judge has requested a vote on
whether to rehear either matter en banc. Fed. R. App. P. 35.
The petitions for rehearing en banc are DENIED. No future
petitions will be entertained.
 NAVAJO NATION V. USDOI 7

OPINION

GOULD, Circuit Judge:

In 2003, the Navajo Nation (the Nation) sued the
Department of the Interior (Interior), the Secretary of the
Interior (the Secretary), the Bureau of Reclamation, and the
Bureau of Indian Affairs (collectively, the Federal
Appellees), bringing claims under the National
Environmental Policy Act (NEPA) and a breach of trust
claim for failure to consider the Nation’s as-yet-
undetermined water rights in managing the Colorado River.
Several parties, including Arizona, Nevada, and various state
water, irrigation, and agricultural districts and authorities
(collectively, the Intervenors), intervened to protect their
interests in the Colorado’s waters. In a prior appeal, we held
that while the Nation lacked Article III standing to bring its
NEPA claims, its breach of trust claim was not barred by
sovereign immunity, and we remanded to the district court.
Navajo Nation v. Dep’t of Interior (Navajo I), 876 F.3d
1144, 1174 (9th Cir. 2017). After re-considering the breach
of trust claim, the district court dismissed the Nation’s
complaint because of its view that any attempt to amend the
complaint was futile. The district court held that it lacked
jurisdiction to decide the claim because the Supreme Court
reserved jurisdiction over allocation of rights to the Colorado
River in Arizona v. California (Arizona I), 373 U.S. 546
(1963) (opinion); accord Arizona v. California (1964
Decree), 376 U.S. 340, 353 (1964) (decree). The district
court also held that the Nation did not identify a specific
treaty, statute, or regulation that imposed an enforceable
trust duty on the federal government that could be vindicated
in federal court. The Nation appealed.

We conclude that the district court erred in dismissing
the complaint because, in contrast to the district court’s
8 NAVAJO NATION V. USDOI

determination, the amendment was not futile. Although the
Supreme Court retained original jurisdiction over water
rights claims to the Colorado River in Arizona I, the Nation’s
complaint does not seek a judicial quantification of rights to
the River, so we need not decide whether the Supreme
Court’s retained jurisdiction is exclusive. And contrary to
the Intervenors’ arguments on appeal, the Nation’s claim is
not barred by res judicata, despite the federal government’s
representation of the Nation in Arizona I. Finally, the district
court erred in denying the Nation’s motion to amend and in
dismissing the Nation’s complaint, because the complaint
properly stated a breach of trust claim premised on the
Nation’s treaties with the United States and the Nation’s
federally reserved Winters rights, especially when
considered along with the Federal Appellees’ pervasive
control over the Colorado River. We remand to the district
court with instructions to permit the Nation to amend its
complaint.

I

The Nation is a federally recognized Indian tribe that has
signed two treaties with the United States. In ratifying the
first treaty in 1849, the United States placed the Navajo
people “under the exclusive jurisdiction and protection of the
. . . United States,” providing “that they are now, and will
forever remain, under the aforesaid jurisdiction and
protection.” Treaty with the Navaho, 1849 art. I (Sep. 9,
1849), 9 Stat. 974. The Navajo Reservation (the
“Reservation”) was established as the “permanent home” of
the Nation by the 1868 Treaty between the United States of
America and the Navajo Tribe of Indians, 1868 art. XIII
(June 1, 1868), 15 Stat. 667 (1868 Treaty). The Reservation
was later expanded by executive orders and acts of Congress.
 NAVAJO NATION V. USDOI 9

The Reservation sprawls across Arizona, New Mexico,
and Utah, and lies almost entirely within the drainage basin
of the Colorado River. The Colorado River flows along and
defines a significant part of the Reservation’s western
border. Because much of the land in the Colorado River
drainage basin is arid, competition for water from the
Colorado River and its tributaries is fierce.

To resolve disputes arising from water scarcity, rights to
the Colorado River’s waters are allocated through a series of
federal treaties, statutes, regulations, and common law
rulings; Supreme Court decrees; and interstate compacts.
Collectively, this legal regime is known as the “Law of the
River.”

A

The Law of the River begins with the 1922 Colorado
River Compact (1922 Compact), which split the Colorado
River water equally between two groups of states: the
“Upper Basin” states, consisting of Colorado, New Mexico,
Utah, and Wyoming, and the “Lower Basin” states: Arizona,
California, and Nevada. 1922 Compact art. II, reprinted in
70 Cong. Rec. 324 (Dec. 10, 1928). Each group collectively
received 7.5 million acre-feet per year (mafy) of water. Id.
art. III. The 1922 Compact did not, however, apportion the
7.5 mafy among the individual states in either the Upper or
Lower Basin. See id. art. VIII. Nor did it “affect[] the
obligations of the United States of America to Indian tribes.”
Id. art. VII.

Six years later, Congress conditionally approved the
1922 Compact through the Boulder Canyon Project Act
(BCPA). 43 U.S.C. § 617 et seq. The BCPA allowed
Interior to construct the Hoover Dam and a reservoir at Lake
Mead. See id. § 617. It empowered the Secretary to contract
10 NAVAJO NATION V. USDOI

for the storage and delivery of water in Lake Mead. See id.
Finally, it authorized the Lower Basin States to negotiate a
second compact dividing their 7.5 mafy share: 4.4 mafy to
California, 2.8 to Arizona, and 0.3 to Nevada. See 43 U.S.C.
§ 617c(a).

The 1922 Compact—including the second compact
apportionment—was to take effect once all three Lower
Basin states ratified it. See id. But Arizona, displeased with
the Compact’s terms, failed to ratify it. So the issue of how
to share the Lower Basin States’ apportionment went
unresolved. See Arizona I, 373 U.S. at 561–62.
Nonetheless, because six of the seven Basin states ratified
the BCPA, the Secretary began contracting for water with
the Lower Basin states. 1 Id. at 562.

In 1952, still dissatisfied with its allotment, Arizona sued
California in the Supreme Court, invoking the Court’s
original jurisdiction. Id. at 550–51. Nevada and other Basin
States intervened, as did the United States. Id. at 551.

In proceedings before a Special Master, the United States
asserted claims to various water sources in the Colorado
River Basin on behalf of twenty-five tribes. But the United
States only asserted claims to the Colorado River
mainstream on behalf of five tribes, and the Nation was not
among them. Instead, the United States at that time limited
the Nation’s claim to the Little Colorado River, one of the
tributaries in the Colorado River system. Navajo I, 876 F.3d
at 1156 n.13. The Nation, along with other tribes, sought the

1
The BCPA lowered the 1922 Compact’s ratification threshold: six
states would suffice for ratification as long as California was among
them and committed to a ceiling on its apportionment. See 43 U.S.C.
§ 617c(a).
 NAVAJO NATION V. USDOI 11

appointment of a Special Assistant Attorney General to
represent their interests, but their request was denied. The
Nation also sought to intervene in proceedings before the
Special Master, but its motion to intervene was denied at the
United States’ urging. See Response of the United States to
the Motion on Behalf of the Navajo Tribe of Indians for
Leave to Intervene, Arizona I, 373 U.S. 546 (No. 8,
Original).

The Supreme Court issued its decree in 1964. See 1964
Decree, 376 U.S. 340. The Court excluded the Little
Colorado River—and therefore the Nation’s claim—from
the adjudication, along with other tributaries in the river
system. See id. art. VIII(B), 376 U.S. at 352–53. It also
affirmed the apportionment of the first 7.5 mafy among the
Lower Basin States as specified in the BCPA and the
accompanying second compact. Id. art. II(B), 376 U.S. at
341–42. The Decree stated that in years where there is less
than 7.5 million acre-feet available in the Lower Basin,
Interior must first “provide[] for satisfaction of present
perfected rights in the order of their priority dates without
regard to state lines.” Id. art. II(B)(3), 376 U.S. at 342.
Then, “after consultation with the parties to major delivery
contracts and such representatives as the respective States
may designate, [the Secretary] may apportion the amount
remaining available for consumptive use in such manner as
is consistent with” the BCPA, the 1964 Decree, and other
applicable federal statutes. Id.

The 1964 Decree also determined the Winters rights of
the five tribes for whom the federal government asserted
federally reserved rights. See id. at 344–45. Under the
Winters doctrine, “when the Federal Government withdraws
its land from the public domain” for the purpose of
establishing an Indian reservation, “the Government, by
12 NAVAJO NATION V. USDOI

implication, reserves appurtenant water then unappropriated
to the extent needed to accomplish the purpose of the
reservation.” Cappaert v. United States, 426 U.S. 128, 138
(1976); see Winters v. United States, 207 U.S. 564, 576
(1908).

Water is essential to life on earth, see Sandra Alters,
Biology: Understanding Life 39 (3d ed. 2000), and it is
particularly essential for healthy human societies. 2 Further,
beyond the general import of water for societies, in the
specific case of the Navajo Nation, news reports have
indicated that the Nation’s shortage of water have in part
caused exacerbation of the risks from COVID-19. Many
homes on the Reservation lack running water, making it
difficult for tribal members to wash their hands regularly.
See Ian Lovett et. al, Covid-19 Stalks Large Families in
Rural America, Wall St. J. (June 7, 2020),
https://www.wsj.com/articles/covid-19-households-spread-
coronavirus-families-navajo-california-second-wave-
11591553896. The Nation has as a result been particularly
affected by the current pandemic, with a death rate

2
It is by no accident that many of the world’s ancient civilizations
were born in places such as the Tigris-Euphrates delta, and the valleys
of the Nile, Indus, and Yellow Rivers. Pierre-Louis Viollet, Water
Engineering in Ancient Civilizations9 (Forrest M. Holly trans., 2017).
The engineers of classical Rome built a vast network of aqueducts that,
at its peak, spanned over 250 miles in length. During the Last Gothic
War, King Vitiges led an army of Ostrogoths to the gates of Rome itself.
The invaders encircled the city and blocked off the aqueducts, keenly
aware that the Romans could not survive a prolonged siege without
access to water. See Peter J. Aicher, Guide to the Aqueducts of Ancient
Rome 6 (1995). In more recent times, Israel, faced with a paucity of
water, has developed techniques for managing wastewater and pioneered
desalinization techniques. In 2011, Israel desalinated 296 million cubic
meters (MCM) of water out of sea water, and forty-five MCM out of
brackish water. Water Policy in Israel 5 (Nir Becker ed., 2013).
 NAVAJO NATION V. USDOI 13

significantly higher than that of many other parts of the
country. See id. 3

In Winters, the United States, acting as trustee of the Fort
Belknap Tribe, sought to enjoin upstream diversions on
Montana’s Milk River from interfering with the Fort
Belknap Reservation’s downstream diversions. See Winters,
207 U.S. at 565. Although the 1888 treaty that established
the Reservation made no express provision for tribal water
rights to the Milk River, the United States maintained that
the water had been impliedly reserved to fulfill the purpose
of the reservation as a “permanent home and abiding place”
for the Fort Belknap Tribe. Id. The Court agreed, noting
that the Reservation lands “were arid, and, without
irrigation, were practically valueless.” Id. at 576. The Court
applied the Indian canons of construction, under which
ambiguities in agreements and treaties with tribes “will be
resolved from the standpoint of the Indians,” and held that
the Tribe was entitled to federally reserved rights to the Milk
River. Id.; see id. at 576–77.

Winters set a “solid foundation” for later decisions that
reaffirmed the scope of Indian reserved water rights. Robert
T. Anderson, Indian Water Rights and the Federal Trust
Responsibility, 46 Nat. Res. J. 399, 414 (2006). Subsequent
decisions have established that these rights are determined
by federal, not state law. See 1 Cohen’s Handbook of
Federal Indian Law § 19.03 (Nell Jessup Newton ed., 2019)

3
The vast majority of deaths on the Reservation due to COVID-19
are among people aged sixty and older, including the hataałii, traditional
medicine men and women entrusted with preserving the Nation’s
cultural heritage. Jack Healy, Tribal Elders Are Dying From the
Pandemic, Causing a Cultural Crisis for American Indians, N.Y. Times
(Jan. 12, 2021), https://www.nytimes.com/2021/01/12/us/tribal-elders-
native-americans-coronavirus.html.
14 NAVAJO NATION V. USDOI

(Cohen’s Handbook). Moreover, tribal water rights may
trump water rights of state users, even when those users have
been drawing from the water source for a longer time. See
id.

In awarding five tribes federally reserved water rights,
the Arizona Court reaffirmed the Winters doctrine, noting
that “most of the [reservation] lands were of the desert
kind—hot, scorching sands—and . . . water from the
[Colorado] river would be essential to the life of the Indian
people and to the animals they hunted and the crops they
raised.” Arizona I, 373 U.S. at 599. These five tribes
received rights to water commensurate with the “practically
irrigable acreage” within each tribe’s reservation. Id. at 600;
see 1964 Decree art. II(D), 376 U.S. at 343–45. However,
the Supreme Court declined to adjudicate the claims of the
twenty other tribes for whom the United States asserted
claims—including the Nation’s. Arizona I, 373 U.S. at 595
(“While the [Special] Master passed upon some of these
claims, he declined to reach others, particularly those
relating to tributaries. We approve his decision as to which
claims required adjudication . . . .”).

B

Federal Appellees, through Interior and its Secretary,
exercise pervasive control over the Colorado River pursuant
to the BCPA, the 1964 Decree, and other components of the
Law of the River. See id. at 593. The Secretary has
discretion to apportion shortfalls in years of shortage, see id.
at 593–94, and also has the authority to determine whether
there is a surplus or shortage of water each year, see 1964
Decree, art. II(B)(2)–(3), 376 U.S. at 342.

In 1968, Congress enacted the Colorado River Basin
Project Act (the “Basin Act”), which requires Interior to
 NAVAJO NATION V. USDOI 15

manage Lake Mead, Lake Powell, and related facilities in
coordination and under long-range operating criteria.
43 U.S.C. § 1552(a). Each year, Interior must determine
whether there will be enough water to satisfy the 7.5 mafy
budgeted among the Lower Basin states, and whether and
how much “surplus” water will be available. See 73 Fed.
Reg. 19,873, 19,875 (Apr. 11, 2008). In 2001 and 2007,
Interior adopted “surplus” and “shortage” guidelines to
clarify how it determines whether a particular year was a
“shortage” or “surplus” year. See 66 Fed. Reg. 7772 (Jan.
25, 2001); 73 Fed. Reg. 19,873 (Apr. 11, 2008).

Before adopting the shortage guidelines, the Secretary
published a draft environmental impact statement (EIS)
discussing Indian Trust Assets, which are defined as legal
interests in assets held in trust by the federal government for
federally recognized tribes. See Final Environmental Impact
Statement, Colorado River Interim Guidelines for Lower
Basin Shortages and Coordinated Operations for Lake
Powell and Lake Mead (Shortage Guidelines FEIS) 3-87
(Oct. 2007). The EIS acknowledges that under the Winters
doctrine, the federal government impliedly “reserved water
in an amount necessary to fulfill the purposes of an Indian
reservation” for the Navajo Reservation. Id. at 3-96. The
EIS also states that while “[t]he existence of a federally
reserved right for the Navajo Nation to mainstream
Colorado River has not been judicially determined at this
time[, u]nquantified water rights of the Navajo Nation are
considered an [Indian Trust Asset].” Id.

II

The Nation filed a complaint against Federal Appellees
under the Administrative Procedure Act (APA), 5 U.S.C.
§§ 701–706, challenging the 2001 Surplus Guidelines.
Navajo I, 876 F.3d at 1159. The Nation alleged that Federal
16 NAVAJO NATION V. USDOI

Appellees violated the National Environmental Policy Act
(NEPA), 42 U.S.C. § 4321 et seq., and breached its trust
obligations based on the Federal Appellees’ management of
the Colorado River without considering or meeting the
Nation’s unquantified federal reserved water rights and
unmet water needs, Navajo I, 876 F.3d at 1159. Several
parties—Arizona, Nevada, and various state water,
irrigation, and agricultural districts and authorities
(collectively, “Intervenors”)—intervened to protect their
interests in the Colorado’s waters. Id. The district court
dismissed the complaint, holding that the Nation lacked
standing to bring its NEPA claims and that its breach of trust
claim was barred by sovereign immunity.

On appeal, we agreed with the district court that the
Nation lacked standing to bring its NEPA claims but
reversed and remanded on the breach of trust claim. Id.
at 1174. We held that the waiver of sovereign immunity in
§ 702 of the APA “applie[d] squarely to the Nation’s breach
of trust claim.” Id. at 1173. Because the breach of trust
claim was not barred by sovereign immunity, we instructed
the district court to fully consider the claim on its merits,
“after entertaining any request to amend the claim more fully
to flesh it out.” Id.

On remand, the Nation twice moved for leave to file an
amended complaint. The Proposed Third Amended
Complaint (TAC) alleged that the Federal Appellees have
failed to (1) “determine the quantities and sources of water
required to make the Navajo Nation a permanent homeland
for the Navajo People,” and (2) “protect the sovereign
interests of the Navajo Nation by securing an adequate water
supply to meet those homeland purposes.” The Intervenors
opposed both motions to amend, arguing that because the
United States could have asserted the Nation’s claim to the
 NAVAJO NATION V. USDOI 17

mainstream of the Colorado River in the Arizona v.
California litigation and the rights to the River were fully
adjudicated in that action, the Nation’s claim was barred by
res judicata.

The district court denied both motions to amend and
dismissed the Nation’s complaint with prejudice. The
district court held that although a general trust relationship
exists between the United States and the tribes, the Nation
failed to identify a specific trust-creating statute, regulation,
or other form of positive law that the federal government
violated. And though the Nation argued that such a specific
trust obligation is created under the Winters doctrine, the
district court held that a determination of whether Winters
rights attached to the mainstream of the Colorado River was
jurisdictionally barred by the Supreme Court’s reservation
of jurisdiction in Arizona v. California. We conclude that
the Nation’s claim does not implicate the Court’s reservation
of jurisdiction, and that it therefore was error for the district
court not to grapple with the scope of Winters rights
available to the Nation in connection with its current
requests.

The district court further reasoned that even if it could
decide the breach of trust claim, Winters rights alone do not
give rise to specific and enforceable trust duties on the
federal government. The district court also held that none of
the treaties, statutes, and regulations that the Nation cited in
support of its trust claim were “specific . . . trust-creating
statute[s] or regulation[s] that the Government violated.”
Finally, the district court held that the Nation could not
allege a common law cause of action for breach of trust that
is “wholly separate from any statutorily granted right.”

We disagree with the district court as to the role of
Winters rights in establishing enforceable trust duties.
18 NAVAJO NATION V. USDOI

Winters rights are necessarily implied in each treaty in which
the government took land from Native Americans and
established reservations that were to be permanent homes for
them. That was the case with the Nation’s reservation.
Federal Appellees have an irreversible and dramatically
important trust duty requiring them to ensure adequate water
for the health and safety of the Navajo Nation’s inhabitants
in their permanent home reservation.

Because the district court concluded that the Nation’s
attempts to amend its complaint were futile, the district court
denied the motion to amend and dismissed the complaint.
The Nation timely appealed. Although the district court did
not decide the res judicata issue in dismissing the Nation’s
complaint, Intervenors assert that res judicata defense on
appeal.

This appeal presents three issues. First, we determine
whether the Nation’s breach of trust claim falls within the
Supreme Court’s reserved jurisdiction in Arizona v.
California. If it does, we decide whether that jurisdiction is
not only reserved, but also exclusive. Second, we determine
whether the Nation’s claim is barred by res judicata. Third,
we decide whether the Nation could properly state a claim
for breach of trust such that amendment was not futile.

III

We review a district court’s denial of a motion to amend
a complaint for abuse of discretion. Wheeler v. City of Santa
Clara, 894 F.3d 1046, 1051 (9th Cir. 2018). “A district
court’s exercise of discretion based on an erroneous
interpretation of the law constitutes an abuse of discretion.”
Ahlmeyer v. Nev. Sys. of Higher Educ., 555 F.3d 1051, 1055
(9th Cir. 2009). Moreover, “[d]ismissal without leave to
amend is improper unless it is clear, upon de novo review,
 NAVAJO NATION V. USDOI 19

that the complaint could not be saved by any amendment.”
Polich v. Burlington N., Inc., 942 F.2d 1467, 1472 (9th Cir.
1991). Finally, we review a district court’s decision to
dismiss for lack of subject matter jurisdiction de novo.
DaVinci Aircraft, Inc. v. United States, 926 F.3d 1117, 1122
(9th Cir. 2019).

IV

A

We begin with the jurisdictional question. The district
court determined it could not decide the Nation’s breach of
trust claim because it falls within the Supreme Court’s
reserved jurisdiction under Article IX of the 1964 Decree.
Article IX provides that:

Any of the parties may apply at the foot of
this decree for its amendment or for further
relief. The Court retains jurisdiction of this
suit for the purpose of any order, direction, or
modification of the decree, or any
supplementary decree, that may at any time
be deemed proper in relation to the subject
matter in controversy.

1964 Decree, art. IX, 376 U.S. at 353. The parties and the
district court assumed that this provision reserves the
Supreme Court’s exclusive jurisdiction over—and strips
lower courts of jurisdiction to determine—whether the
Nation has water rights to a specific allocation from the
mainstream of the Colorado River. But in attempting to
avoid Article IX’s jurisdictional bar, the Nation represents
that it does not seek a judicial determination of its rights to
the Colorado. The Nation argues that it merely seeks an
injunction ordering the Federal Appellees to investigate the
20 NAVAJO NATION V. USDOI

Nation’s needs for water, to develop a plan to meet those
needs, and to exercise its authority over the management of
the Colorado River consistent with that plan. Under this
reading of the Nation’s claim, the district court only had to
consider whether the Nation needs water to fulfill the
promise of establishing the Navajo Reservation as a
homeland for the Nation’s people.

We agree with the Nation’s characterization of its claim.
A plain reading of the Nation’s complaint makes clear that it
does not seek a quantification of its rights in the Colorado
River. The Nation seeks an injunction “[r]equiring the
Federal Appellees . . . (1) to determine the extent to which
the Navajo Nation requires water . . . (2) to develop a plan to
secure the water needed; (3) to exercise their authorities,
including those for the management of the Colorado River,
in a manner that does not interfere with the plan to secure the
water needed . . . and (4) to require the Federal Appellees to
analyze their actions . . . and adopt appropriate mitigation
measures to offset any adverse effects from those actions.”
Granting this scope of relief would not require a judicial
quantification of the Nation’s rights to water from the River.
Nor would it require any modification of the Arizona Decree.
Furthermore, Article VIII(C) of the Decree provides that the
Decree does not affect “[t]he rights or priorities, except as
specific provision is made herein, of any Indian
Reservation.” 1964 Decree, 376 U.S. at 353. As discussed
infra, the Nation’s claim is not determined by any specific
provision in the 1964 Decree, as none addresses the Navajo
Nation’s water rights. The Nation’s breach of trust claim
thus falls outside the scope of the Decree, and our
jurisdiction is proper.

Because the Nation does not seek a judicial
determination of its rights to the waters of the Colorado
 NAVAJO NATION V. USDOI 21

River, we need not resolve the scope of the Supreme Court’s
reserved jurisdiction under Article IX. But we note that the
Supreme Court’s own interpretation of the Decree does not
expressly state whether Article IX’s reserved jurisdiction is
exclusive. In the sequel to Arizona I, the federal government
sought to increase the water allotments for the five tribes that
were awarded federally reserved water rights in the original
litigation, arguing that the earlier calculations of the
practicably irrigable acreage within the reservations were
inaccurate. Arizona v. California (Arizona II), 460 U.S. 605,
608 (1983). The Court denied the request, and stated that if
not for Article IX, the Court would have been barred by res
judicata from re-opening the matter. Id. at 617–18. The
Court explained that Article IX was “mainly a safety net
added to retain jurisdiction and to ensure that we had not, by
virtue of res judicata, precluded ourselves from adjusting the
Decree in light of unforeseeable changes in circumstances.”
Id. at 622. Because the Supreme Court is best positioned to
interpret its own Decree, we defer to the interpretation it laid
out in Arizona II and understand Article IX primarily as an
authorization of jurisdiction, rather than a limitation on it.

Because the Nation neither seeks modification of the
Decree nor seeks to relitigate any issues resolved in the
Arizona cases, see infra, however, we need not resolve the
scope of the Supreme Court’s jurisdiction under Article IX.
We have jurisdiction to consider the Nation’s claim, and the
district court erred in holding otherwise.

B

Having established that we have jurisdiction, we turn to
the Intervenors’ argument that res judicata bars the Nation’s
claim. Intervenors argue that the Nation’s breach of trust
claim is barred by res judicata because the Nation
effectively seeks a judicial determination of its rights to the
22 NAVAJO NATION V. USDOI

Colorado River, which is a claim that the federal government
could have asserted on the Nation’s behalf in Arizona I, but
did not. We reject the Intervenors’ argument because the
Nation’s claim is not barred by res judicata.

In Nevada v. United States, 463 U.S. 110 (1982), the
Supreme Court held that res judicata barred the federal
government from seeking additional water rights for the
Pyramid Lake Tribe beyond the rights the tribe obtained in
previous water rights litigation, id. at 113, 145. The Nevada
Court considered “first if the cause of action which the
Government now seeks to assert is the same cause of action
that was asserted” in previous litigation, and then “whether
the parties in the instant proceeding are identical to or in
privity with” the parties in the previous litigation. Id. at 130
(internal quotation marks omitted). The Court held that the
federal government, in a decades-long adjudication that
began in 1913, sought to “assert . . . the Reservation’s full
water rights.” Id. at 132. Because Nevada involved the same
parties “asserting the same reserved right” as that
adjudicated by the previous litigation, id. at 134, the later
claim was barred.

In this case, by contrast, the Nation asserts a different
claim than the water rights claim the federal government
could have asserted on the Nation’s behalf in Arizona I. The
Nation’s claim, properly understood, is an action for breach
of trust—not a claim seeking judicial quantification of its
water rights. The federal government’s fiduciary duty to the
Navajo Nation was never at issue in Arizona v. California,
and no final judgment was ever entered on the merits of any
question concerning that subject. Cf. Nevada, 463 U.S.
at 129–30. As the Decree does not affect “[t]he rights or
priorities” of Indian Reservation beyond those specifically
enumerated, 1964 Decree, 376 U.S. at 353, the federal
 NAVAJO NATION V. USDOI 23

government’s fiduciary duty to the Nation remains unaltered
by the Arizona litigation.

The Nation’s breach of trust claim is not barred by res
judicata.

C

1

Finally, we address whether the Nation’s attempts to
amend its complaint to plead their substantive breach of trust
claim were futile. The Federal Appellees and the Intervenors
argue that the district court correctly denied the Nation’s
motion for leave to amend its complaint, because it could not
point to any specific treaty provision, statute, or regulation
that imposed a trust obligation on the Federal Appellees. We
disagree and hold that the district court should have allowed
the Nation to amend its complaint.

This circuit first considered the requirements a tribe must
meet to bring a breach of trust action for non-monetary relief
in Morongo Band of Mission Indians v. F.A.A., 161 F.3d 569
(9th Cir. 1998). There, the Morongo Tribe challenged a
Federal Aviation Administration (FAA) proposal that would
have increased air traffic over reservation lands. Id. at 572–
73. The Tribe sought non-monetary relief under the APA,
alleging violations of various statutes and FAA regulations.
Id. at 572. We held that “unless there is a specific duty that
has been placed on the government with respect to Indians,
this responsibility is discharged by the agency’s compliance
with general regulations and statutes not specifically aimed
at protecting Indian tribes.” Id. at 574.

We addressed this issue again in Gros Ventre Tribe v.
United States, 469 F.3d 801 (9th Cir. 2006). There, the Gros
24 NAVAJO NATION V. USDOI

Ventre Tribe alleged that the federal government breached
its trust obligations “by approving, permitting, and failing to
reclaim” two cyanide heap-leach gold mines upriver from
the Tribe’s reservation. Id. at 806. The panel explained that
“an Indian tribe cannot force the government to take a
specific action unless a treaty, statute or agreement imposes,
expressly or by implication, that duty.” Id. at 810 (emphasis
added) (quoting Shoshone-Bannock Tribes v. Reno, 56 F.3d
1476, 1482 (D.C. Cir. 1995)). In holding that the Tribe
failed to identify a treaty, statute, or regulation that would
create an enforceable trust duty, we observed that the Tribe’s
treaties with the federal government “at most . . . merely
recognize[d] a general or limited trust obligation to protect
the Indians against depredations on Reservation lands.” Id.
at 812 (emphasis added). Because the Tribe sought an
injunction requiring the federal government to “manage
resources that exist off of the Reservation,” we held that no
treaty provision imposed an enforceable trust duty that could
be vindicated through injunctive relief. Id. at 812–13
(emphasis added).

Morongo and Gros Ventre establish the governing
standard here. Although Federal Appellees rely on another
strain of cases concerning the need to identify specific
statutory bases for obtaining monetary relief under the
Tucker Act, 28 U.S.C. § 1491, those cases are not apposite.

The fiduciary claim in this case is one for injunctive
relief under § 702 of the APA. In United States v. Mitchell
(Mitchell I), 445 U.S. 535 (1980), individual members of the
Quinault Tribe sued the federal government through the
Tucker Act, 28 U.S.C. § 1491, over alleged mismanagement
of timber resources on their allotted reservation lands,
445 U.S. at 537, 539. The timber was managed by the
Secretary of Interior under the General Allotment Act
 NAVAJO NATION V. USDOI 25

(GAA). Id. at 537. The Supreme Court rejected the tribal
allottees’ argument that the GAA imposed enforceable trust
duties on the federal government to manage tribal timber
resources in a fiduciary capacity. Id. at 546. The Court
explained that when Congress enacted the GAA, it intended
that the federal government hold the land in trust “not
because it wished the Government to control use of the land
and be subject to money damages for breaches of fiduciary
duty, but simply because it wished to prevent alienation of
the land and to ensure that allottees would be immune from
the state taxation.” Id. at 544. The Court remanded the case
to the Court of Claims to consider whether the federal
government could be held liable for breach of trust based on
any other statutes. Id. at 546.

On remand, the Court of Claims held that the
government was subject to suit for money damages based on
various statutes and regulations detailing the federal
government’s responsibilities in managing the tribal timber
resources. United States v. Mitchell (Mitchell II), 463 U.S.
206, 211 (1983). The Supreme Court affirmed, holding that
the regulations and statutes created an enforceable trust
obligation because they accorded the Secretary a “pervasive
role in the sales of timber from Indian lands.” Id. at 219.
The Court observed that a substantive right to sue under the
Tucker Act “must be found in some other source of law, such
as ‘the Constitution, or any Act of Congress, or any
regulation of an executive department.’” Id. at 216 (quoting
28 U.S.C. § 1491). “[T]he claimant must demonstrate that
the source of substantive law he relies upon ‘can fairly be
interpreted as mandating compensation by the Federal
Government for the damages sustained.’” Id. at 216–17
(quoting United States v. Testan, 424 U.S. 392, 400 (1976)).
26 NAVAJO NATION V. USDOI

These Supreme Court decisions concerned suits brought
for money damages under the Tucker Act, 28 U.S.C. § 1491,
and the Indian Tucker Act, 28 U.S.C. § 1505. But this case
involves a claim for injunctive relief brought under § 702 of
the APA, so we are not bound by those decisions.

A more recent decision, United States v. Jicarilla,
564 U.S. 162 (2011), concerned a breach of trust claim in a
discovery context and imported requirements similar to
those stated in the Tucker Act and Indian Tucker Act cases.
In Jicarilla, the Court decided whether the Jicarilla Apache
Nation (the “Tribe”) could assert the “fiduciary exception”
to the attorney-client privilege in a suit against the federal
government, id. at 165. At first, the Tribe sued the
government for breach of trust, seeking monetary damages
for alleged mismanagement of tribal funds. Id. at 166. Then
the parties participated in alternative dispute resolution,
wherein the government refused to produce certain
documents, claiming the attorney-client privilege. Id. So
the Tribe moved to compel production of those documents.
Id. at 167. It asserted the “fiduciary exception” to the
attorney-client privilege, which states that a trustee cannot
assert the privilege against a beneficiary after obtaining legal
advice on how to execute its fiduciary obligations. Id.

The Court held that the Tribe could not compel the
federal government to produce privileged documents in
discovery based on the fiduciary exception, because it failed
to “point to a right conferred by statute or regulation in order
to obtain otherwise privileged information from the
Government against its wishes.” Id. at 178. In doing so, the
Court observed that it had previously “found that particular
‘statutes and regulations . . . clearly establish fiduciary
obligations of the Government’ in some areas.” Id. at 177
(ellipsis in original) (quoting Mitchell II, 463 U.S. at 226).
 NAVAJO NATION V. USDOI 27

But the Court also explained that “[o]nce federal law
imposes such duties, the common law ‘could play a role’” in
defining the scope of those duties. Id. (quoting United States
v. Navajo Nation, 556 U.S. 287, 301 (2009)). Again,
Jicarilla was at bottom a suit for monetary relief. Its ruling
must be understood against that background.

2

Federal Appellees contend that under these precedents,
the Nation has failed to state a breach of trust claim because
it cannot point to any treaty, statute, or regulation that
imposes an affirmative trust duty on the federal government
to ensure that the Nation has an adequate water supply. We
disagree.

Here, the injunctive relief the Nation seeks would not
require the federal government to manage off-reservation
resources. Instead, the Nation seeks an injunction
compelling the Secretary to determine the extent to which
the Reservation requires water from sources other than the
Little Colorado River to fulfill the Reservation’s purpose of
establishing a permanent homeland for the Nation. The
mainstream of the Colorado River is appurtenant to the
Nation and defines a significant segment of the
Reservation’s western boundary.

Moreover, neither Morongo nor Gros Ventre nor
Jicarilla involved claims to vindicate Winters rights, which
provide the foundation of the Nation’s claim here. Unlike
the plaintiffs in those cases, the Nation, in pointing to its
reserved water rights, has identified specific treaty, statutory,
and regulatory provisions that impose fiduciary obligations
on Federal Appellees—namely, those provisions of the
Nation’s various treaties and related statutes and executive
orders that establish the Navajo Reservation and, under the
28 NAVAJO NATION V. USDOI

long-established Winters doctrine, give rise to implied water
rights to make the reservation viable.

Under Winters, the federal government “reserve[d]
appurtenant water then unappropriated to the extent needed
to accomplish” the purpose of establishing the Reservation
as a permanent homeland for the Navajo people. Navajo I,
876 F.3d at 1155 (quoting Cappaert, 426 U.S. at 138). In
Colville Confederated Tribes v. Walton, 647 F.2d 42 (9th
Cir. 1981), we noted that while “[t]he specific purposes of
an Indian reservation . . . were often unarticulated,” “[t]he
general purpose, to provide a home for the Indians, is a broad
one and must be liberally construed,” id. at 47. It is clear
that the Reservation cannot exist as a viable homeland for
the Nation without an adequate water supply. As the Court
observed in Arizona I:

Most of the land in [the reservations
appurtenant to the Colorado River] is and
always has been arid. If the water necessary
to sustain life is to be had, it must come from
the Colorado River or its tributaries. It can
be said without overstatement that when the
Indians were put on these reservations they
were not considered to be located in the most
desirable area of the Nation. It is impossible
to believe that when Congress created the
great Colorado River Indian Reservation and
when the Executive Department of this
Nation created the other reservations they
were unaware that most of the lands were of
the desert kind—hot, scorching sands—and
that water from the river would be essential
to the life of the Indian people and to the
 NAVAJO NATION V. USDOI 29

animals they hunted and the crops they
raised.

373 U.S. at 598–99.

We stress that Winters rights are long-established and
clearly qualify as rights “by implication” under a treaty.
Gros Ventre, 469 F.3d at 810 (quoting Shoshone-Bannock,
56 F.3d at 1482). Those necessarily implied rights are just
as important as express ones. It is not our province to modify
the Supreme Court’s definitive law establishing water rights
as contained in treaties establishing Native American
reservations, whether express or not. None of the twists and
turns in the responsible federal agencies’ and courts’
historical treatment of Indian law has brought the Winters
declaration of necessarily implied water rights into question.

We hold in particular that, under Winters, Federal
Appellees have a duty to protect the Nation’s water supply
that arises, in part, from specific provisions in the 1868
Treaty that contemplated farming by the members of the
Reservation. The Treaty provides that individual members
of the Nation may select plots of land if they “desire to
commence farming.” 1868 Treaty, art. V. Tribal members
who took up farming would be entitled to “seeds and
agricultural implements” to help make this transition. Id. art.
VII. The Treaty’s farming-related provisions, which sought
to encourage the Nation’s transition to an agrarian lifestyle,
would have been meaningless unless the Nation had
sufficient access to water. 4 Indeed, in Winters itself, the

4
In the Nation’s first motion for leave to file a third amended
complaint, the Nation sought to add, in addition to its breach of fiduciary
duty claim, a claim for breach of the 1849 and 1868 Treaties, but later
omitted that claim from its renewed motion. On remand, the district
30 NAVAJO NATION V. USDOI

Court explained that at the time the Fort Belknap Tribe
signed its treaty with the federal government, it was the
government’s policy to change the Tribe’s “habits and
wants” to those of “a pastoral and civilized people.”
Winters, 207 U.S. at 576. We do not pass judgment on the
wisdom of such a policy, nor on the merits of particular
allegations that may be offered relating to agrarian rights, but
it is clear that the Winters Court based its holding in large
part on the fact that without water, the reservation lands
could not support an agrarian lifestyle in accordance with
government policy. See id. (“The lands were arid, and,
without irrigation, were practically valueless.”).

That the farming provisions in the 1868 Treaty may
serve as the “specific statute” that satisfies Jicarilla,
Morongo, and Gros Ventre is consistent with more general
principles concerning the interpretation of treaties between
the United States and Indian tribes. The Supreme Court has
explained: “A treaty, including one between the United
States and an Indian tribe, is essentially a contract between
two sovereign nations.” Washington v. Wash. State Com.
Passenger Fishing Vessel Ass’n, 443 U.S. 658, 675,
modified sub nom. Washington v. United States, 444 U.S.
816 (1979) (citing Lone Wolf v. Hitchcock, 187 U.S. 553
(1979)). We have inferred a promise of water rights into
treaties that contained no explicit reservation of those rights.
See, e.g., Arizona I, 373 U.S. at 599; Agua Caliente Band of
Cahuilla Indians v. Coachella Valley Water Dist., 849 F.3d
1262, 1268 (9th Cir. 2017).

We did so in United States v. Adair, 723 F.2d 1394 (9th
Cir. 1983), for example, where the Klamath Tribe’s treaty

court is instructed that the Nation should be permitted to amend its
complaint in this respect if it seeks to do so.
 NAVAJO NATION V. USDOI 31

with the United States merely preserved the right to “hunt,
fish, and gather on their reservation,” Id. at 1398. We
recognized that a main purpose of the treaty was to “secure
to the Tribe a continuation of its traditional hunting and
fishing lifestyle.” Id. at 1409. We reasoned that this purpose
would have been defeated unless the Klamath Tribe had the
right to enjoy and use water sufficient to ensure an adequate
supply of game and fish. See id. at 1411. Although the
claimed water rights at issue in that case were “essentially
nonconsumptive in nature,” id. at 1418, Adair stands for the
broader proposition that we may read water rights into a
treaty where those rights are necessary to fulfill the treaty’s
primary purpose. See United States v. Washington, 853 F.3d
946, 965 (9th Cir. 2017) (“Thus, even if Governor Stevens
had made no explicit promise, we would infer, as in Winters
and Adair, a promise to ‘support the purpose’ of the
Treaties.”).

Interior’s documents also demonstrate that the Federal
Appellees have acknowledged their trust responsibilities to
protect the Nation’s Winters rights. For example, the final
EIS relating to Interior’s shortage guidelines acknowledges
that the federal government impliedly “reserved water in an
amount necessary to fulfill the purposes of” the Navajo
Reservation. Shortage Guidelines FEIS, 3-96. The EIS also
states that the Nation’s unquantified water rights are
considered an Indian Trust Asset, which Interior recognizes
as interests that the federal government holds in trust for
recognized Indian tribes, and that the federal government
must protect. Id.

The Nation’s breach of trust claim is also strengthened
and reinforced by the Secretary’s pervasive control over the
Colorado River. The BCPA, which requires the United
States and all Colorado River users to “observe and be
32 NAVAJO NATION V. USDOI

subject to and controlled by” the 1922 Compact, apportioned
the Colorado River’s waters among the Lower Basin states.
43 U.S.C. § 617g(a). But within the general allocation of
water that the 1922 Compact entails, the Secretary has
pervasive authority “both to carry out the allocation of the
waters of the main Colorado River among the Lower Basin
States and to decide which users within each State would get
water.” Arizona I, 373 U.S. at 580.

In this respect, the Supreme Court’s reasoning in
Mitchell II is pertinent: just as the statutes and regulations in
that case gave the Secretary a “pervasive role in the sales of
timber from Indian lands,” 463 U.S. at 219, so too do the
BCPA and other components of the Law of the River confer
broad authority upon the Secretary to manage and contract
for Colorado River water, see, e.g., BCPA, 43 U.S.C. § 617d
(“No person shall have or be entitled to have the use for any
purpose of the water stored as aforesaid except by contract
made as herein stated.”). This pervasive control over the
Colorado River, coupled with the Nation’s Winters rights,
outlines the scope of Federal Appellees’ trust duties.

Our holding is consistent with the Supreme Court’s
decision in United States v. Navajo Nation. Although the
Court there held that “[t]he Federal Government’s liability
cannot be premised on control alone,” 556 U.S. at 301, the
Court also explained that once a plaintiff identifies a specific
duty-imposing treaty, statute, or regulation, “then trust
principles (including any such principles premised on
‘control’) could play a role in ‘inferring that the trust
obligation [is] enforceable by damages.’” Id. (quoting
United States v. White Mountain Apache Tribe, 537 U.S.
465, 473 (2003)). The Nation—which in any case does not
here seek money damages—has identified a specific duty-
imposing treaty, as we have explained.
 NAVAJO NATION V. USDOI 33

To summarize: We hold that the Nation has successfully
identified specific treaty, statutory, and regulatory
provisions that, taken together, anchor its breach of trust
claim. First, we have the implied treaty rights recognized in
Winters, which in itself gives the Tribe the right to proceed
on a breach of trust claim here; second, the 1868 Treaty,
which recognizes the Nation’s right to farm Reservation
lands and, under Adair, gives rise to an implied right to the
water necessary to do so; third, the BCPA and other statutes
that grant the Secretary authority to exercise pervasive
control over the Colorado River; and fourth and finally, the
Nation has pointed to Interior regulations and documents in
which Federal Appellees have undertaken to protect Indian
Trust Assets, including the Nation’s as-yet-unquantified
Winters rights.

Having established that a fiduciary duty exists, we hold
that common-law sources of the trust doctrine and the
control the Secretary exercises over the Colorado River
firmly establish the Federal Appellees’ duty to protect and
preserve the Nation’s right to water. Under Winters, when
the federal government took the Reservation into trust, it
“reserve[d] appurtenant water then unappropriated to the
extent needed to accomplish” that purpose. Navajo I,
876 F.3d at 1155 (quoting Cappaert, 426 U.S. at 138).
These rights are recognized as reserved by treaty, applying
the canon that in “agreements and treaties with the Indians,
ambiguities occurring will be resolved from the standpoint
of the Indians.” Winters, 207 U.S. at 576; see Washington,
853 F.3d at 965. Though water rights are not expressly
stated in the Nation’s treaties with the United States, the
Winters rights that attach to the Reservation are sufficiently
well-established to create an implied fiduciary obligation on
the Federal Appellees. See Gros Ventre, 469 F.3d at 810
(noting that a specific duty can be imposed by “a treaty,
34 NAVAJO NATION V. USDOI

statute or agreement . . . expressly or by implication.”)
(quoting Shoshone-Bannock, 56 F.2d at 1482).

We recognize that no court has yet quantified the
Nation’s Winters rights. But the fault for the exceedingly
long delay in that respect, if any, lies with Federal Appellees.
As trustee, the federal government has the power to not only
bring water rights claims on behalf of the tribes, but also to
bind them in litigation. See Nevada, 463 U.S. at 135. When
the Nation tried to intervene in Arizona v. California, the
federal government opposed the Nation’s motion. And in
the more than half of a century since the Supreme Court
issued its 1964 Decree, the Nation has never had its Winters
rights adjudicated or quantified by any court. 5 This result is
but one example of what a commentator has described as the
federal government’s failure “to secure, protect, and develop
adequate water supplies for many Indian tribes.” Cohen's
Handbook § 19.06. Indeed, “[i]n the history of the United
States Government’s treatment of Indian tribes, its failure to
protect Indian water rights for use on the reservations it set
aside for them is one of the sorrier chapters.” 6 Id. (citing
National Water Comm’n, Water Policies for the Future:
Final Report to the President and to the Congress of the
United States, 474–75 (1973)); see also Anderson, supra, at
400.

5
The Nation is actively seeking water from various sources in other
litigation. See generally Navajo I, 876 F.3d at 1156 n.14.
6
Perhaps recognizing this failure, some members of Congress have
proposed legislation that would empower the Administrator of the
Environmental Protection Agency to “give priority to projects that
respond to emergency situations where a lack of access to clean drinking
water threatens the health of Tribal populations” in the Columbia River
Basin. S. 421, 117th Cong. § 2 (2021).
 NAVAJO NATION V. USDOI 35

The Supreme Court could not have intended to hamstring
the Winters doctrine—which has remained good law for
more than one hundred years—by preventing tribes from
seeking vindication of their water rights by the federal
government when the government has failed to discharge its
duties as trustee. Such a perverse reading of the Court’s
precedents would render ineffectual the federal
government’s promise to “charge[] itself with moral
obligations of the highest responsibility and trust,” Seminole
Nation v. United States, 316 U.S. 286, 297 (1942), by
ensuring that the tribes of this country can make their
reservation lands livable. This principle takes on even more
importance in an era in which the COVID-19 pandemic
renders reservation lands more dangerous to tribal
members—particularly when they lack adequate water for
health and safety purposes.

The Nation’s attempts to amend its complaint were not
futile. The Nation can state a cognizable claim for breach of
trust because it has identified specific regulations and treaty
provisions that can “fairly be interpreted,” Mitchell II,
463 U.S. at 218, as establishing Federal Appellees’ fiduciary
obligations to ensure that the Nation’s Reservation has the
water it needs to exist as a viable homeland for the Navajo
people.

At this early stage of litigation, we decline to address
whether the Nation’s Winters rights include rights to the
mainstream of the Colorado River or to any other specific
water sources. We hold only that the Nation may properly
base its breach of trust claim on water rights derived from its
treaties with the United States under Winters, and so may
amend its complaint to so allege.
36 NAVAJO NATION V. USDOI

V

Because the district court’s denial of the Nation’s motion
for leave to amend and subsequent dismissal of the Nation’s
complaint were based on legal errors, the court abused its
discretion. Applying the correct legal principles, we hold
that the Nation’s attempts to amend its complaint were not
futile. We reverse the district court’s dismissal of the
Nation’s complaint and remand to the district court with
instructions to permit amendment to the complaint
consistent with this opinion. 7

REVERSED AND REMANDED.

LEE, Circuit Judge, concurring:

I write separately to emphasize that the Nation’s
proposed injunctive relief should not and does not implicate
the Supreme Court’s retained jurisdiction in Arizona v.
California (1964 Decree), 376 U.S. 340, 353 (1964).

When the Supreme Court first adjudicated the rights to
the Colorado River, it issued a Decree listing the Indian
tribes and other entities holding present perfected rights to
the mainstream. Id. at 344–46. Article IX of the Decree

7
As the concurrence recognizes, we need not and do not decide
whether the Supreme Court’s retained jurisdiction in the 1964 Decree is
exclusive. That is because the Nation’s claim does not seek a
quantification of any rights it may have to the Colorado River
mainstream. If, however, Federal Appellees later determine that they
cannot meet their trust obligation to provide adequate water for the
Nation unless the jurisdictional question is resolved, then they can
petition the Supreme Court for modification of the 1964 Decree.
 NAVAJO NATION V. USDOI 37

“retain[ed] jurisdiction . . . for the purpose of any order,
direction, or modification of the decree, or any
supplementary decree . . .” Id. at 353. Since then, there have
been several iterations of the Arizona v. California litigation,
but none has explicitly addressed whether Article IX
reserves exclusive jurisdiction for adjudication of rights to
the mainstream. See, e.g., Arizona v. California (Arizona II),
460 U.S. 605, 622 (1983).

In this case, the Nation seeks additional water for its
Reservation, and both the parties and the district court
considered whether the Supreme Court’s retained
jurisdiction applied. But our decision does not answer that
question, as the Nation’s Proposed Third Amended
Complaint (“TAC”) does not, on its face, actually seek rights
to the mainstream.

The Nation’s TAC seeks injunctive relief requiring, in
part, that the Federal Defendants “determine the extent to
which the Navajo Nation requires water from sources other
than the Little Colorado River to enable its Reservation to
serve as a permanent homeland for the Navajo Nation and
its members” and “develop a plan to secure the water
needed.” The Nation asserts, and our decision affirms, that
this proposed injunction does not ask the district court to
quantify any rights that the Nation may have to the Colorado
River mainstream. This narrow construction of the proposed
relief is imperative, as it allows the Nation to pursue its
claims without raising the separate and more complex issue
of the Supreme Court’s retained jurisdiction.

Thus, on remand and in all future proceedings, the
TAC’s proposed injunctive relief should not be construed as
implicitly authorizing a reassessment of the rights to the
Colorado River mainstream. In other words, the requested
relief that the Federal Defendants develop a plan to meet the
38 NAVAJO NATION V. USDOI

Nation’s water needs cannot be used as a backdoor attempt
to allocate the rights to the mainstream. If such rights are to
be reassessed, that action may be taken only after resolving
the jurisdictional question raised by Article IX of the 1964
Decree.