Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1484_aplc.pdf
Page Number: 10

Cite as:  599 U. S. ____ (2023) 

7 

Opinion of the Court 

(1938);  Winters  v.  United  States,  207  U. S.  564,  576–577 
(1908);  see  also  Cappaert  v.  United  States,  426  U. S.  128, 
138–139 (1976).  Each of those rights is a stick in the bundle 
of property rights that makes up a reservation. 

This suit involves water.  To help meet their water needs, 
the Navajos obtain water from, among other sources, rivers, 
tributaries, springs, lakes, and aquifers on the reservation.
As  relevant  here,  the  Navajos  do  not  contend  that  the 
United  States  has  interfered  with  their  access  to  water. 
Rather, the Navajos argue that the United States must take
affirmative  steps  to  secure  water  for  the  Tribe—for
example, by assessing the Tribe’s water needs, developing
a plan to secure the needed water, and potentially building
pipelines, pumps, wells, or other water infrastructure.

The Tribe asserts a breach-of-trust claim.  To  maintain 
such a claim here, the Tribe must establish, among other 
things,  that  the  text  of  a  treaty,  statute,  or  regulation
imposed  certain  duties  on  the  United  States.  See  United 
States v. Jicarilla Apache Nation, 564 U. S. 162, 173–174, 
177–178 (2011); United States v. Navajo Nation, 537 U. S. 
488,  506–507  (2003);  United  States  v.  Mitchell,  445  U. S. 
535,  542,  546  (1980).  The  Federal  Government  owes 
judicially enforceable duties to a tribe “only to the extent it 
expressly  accepts  those  responsibilities.”    Jicarilla,  564 
U. S.,  at  177.  Whether  the  Government  has  expressly 
accepted  such  obligations  “must  train  on  specific  rights-
creating or duty-imposing” language in a treaty, statute, or 
regulation.  Navajo  Nation,  537  U. S.,  at  506.    That 
requirement follows from separation of powers principles.
As  this  Court  recognized  in  Jicarilla,  Congress  and  the
President  exercise  the  “sovereign  function”  of  organizing 
and managing “the Indian trust relationship.”  564 U. S., at 
175.  So the federal courts in turn must adhere to the text 
of the relevant law—here, the treaty.1 

—————— 

1 The  Navajos  have  suggested  that  the  Jicarilla  line  of  cases  might