Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-1484_aplc.pdf
Page Number: 9.0

6 

ARIZONA v. NAVAJO NATION 

Opinion of the Court 

sought to “compel the Federal Defendants to determine the 
water required to meet the needs” of the Navajos in Arizona 
and to “devise a plan to meet those needs.”  App. 86.  The 
States of Arizona, Nevada, and Colorado intervened against 
the Tribe to protect those States’ interests in water from the
Colorado River. 

According  to  the  Navajos,  the  United  States  must  do 
more  than  simply  not  interfere  with  the  reserved  water 
rights.  The Tribe argues that the United States also must 
take  affirmative  steps  to  secure  water  for  the  Tribe— 
including 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.  See 
Tr. of Oral Arg. 102 (counsel for Navajo Nation:  “I can’t say
that”  the  United  States’s  obligation  “to  ensure  access”  to 
water 
infrastructure 
whatsoever”).

“would  never 

require 

any 

The  U. S.  District  Court  for  the  District  of  Arizona 
dismissed the Navajo Tribe’s complaint.  In relevant part, 
the District Court determined that the 1868 treaty did not 
impose a duty on the United States to take affirmative steps 
to secure water for the Tribe. 

The U. S. Court of Appeals for the Ninth Circuit reversed,
holding in relevant part that the United States has a duty 
under  the  1868  treaty  to  take  affirmative  steps  to  secure
water  for  the  Navajos.  Navajo  Nation  v.  United  States 
Dept. of Interior, 26 F. 4th 794, 809–814 (2022).  This Court 
granted certiorari.  598 U. S. ___ (2022). 

II 

When the United States establishes a tribal reservation, 
the reservation generally includes (among other things) the 
land, the minerals below the land’s surface, the timber on 
the  land,  and  the  right  to  use  needed  water  on  the 
reservation,  referred  to  as  reserved  water  rights.  See 
United  States  v.  Shoshone  Tribe,  304  U. S.  111,  116–118