Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1484_aplc.pdf
Page Number: 40.0

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

19 

GORSUCH, J., dissenting 

“it is impossible to believe that when . . . the Executive De-
partment of this Nation created the [various] reservations” 
in the arid Southwest it was “unaware that . . . water from 
the [Colorado R]iver would be essential to the life of the In-
dian people and to the animals they hunted and the crops
they raised.”  Arizona I, 373 U. S., at 598–599.  Nor does the 
United  States  dispute  any  of  this.    To  the  contrary,  it 
acknowledges  that  the  Navajo’s  water  rights  very  well 
“may . . . include some portion of the mainstream of the Col-
orado” that runs adjacent to their reservation.  Tr. of Oral 
Arg. 33.

For  our  purposes  today,  that  leaves  just  one  question: 
Can the Tribe state a legally cognizable claim for relief ask-
ing  the  United  States  to  assess  what  water  rights  they 
have?  Not even the federal government seriously disputes 
that  it  acts  “as  a  fiduciary”  of  the  Tribes  with  respect  to
tribal waters it manages.  Arizona II, 460 U. S., at 627–628. 
Indeed,  when  it  comes  to  the  Navajo,  the  United  States
freely admits that it holds certain water rights for the Tribe 
“in trust.”  Tr. of Oral Arg. 40.  And of course, that must be 
so given that the United States exercises pervasive control
over much water in the area, including in the adjacent Col-
orado River.  See Arizona I, 373 U. S., at 564–565. 

Those observations suffice to resolve today’s dispute.  As 
we have seen, that exact coupling—a fiduciary relationship
to a specific group and complete managerial control over the 
property of that group—gives rise to a duty to account.  See 
supra, at 16–17.  The United States, we know, must act in 
a  “legally  [a]dequate”  way  when  it  comes  to  the  Navajo’s
water  it  holds  in  trust.    Arizona  II,  460  U. S.,  at  627.    It 
follows, as the United States concedes, that the federal gov-
ernment  could  not  “legally”  dam  off  the  water  flowing  to 
their  Reservation,  as  doing  so  would  “interfere  with  [the
Tribe’s] exercise of their” water rights.  Tr. of Oral Arg. 13. 
Implicit  in  that  concession  is  another.    Because  Winters 
rights belong to the Navajo themselves, the United States