Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-376_7l48.pdf
Page Number: 85.0

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

3 

THOMAS, J., dissenting 

in the Federal Government have no application to regulat-
ing the domestic child custody proceedings of U. S. citizens 
living within the jurisdiction of States.

I  would  go  no  further.    But,  as  the  majority  notes,  the 
Court’s  precedents  have  repeatedly  referred  to  a  “plenary
power” that Congress possesses over Indian affairs, as well 
as a general “trust” relationship with the Indians.  I have 
searched in vain for any constitutional basis for such a ple-
nary power, which appears to have been born of loose lan-
guage and judicial ipse dixit.  And, even taking the Court’s
precedents as given, there is no reason to extend this “ple-
nary  power”  to  the  situation  before  us  today:  regulating
state-court child custody proceedings of U. S. citizens, who 
may never have even set foot on Indian lands, merely be-
cause the child involved happens to be an Indian. 

I 

State courts usually apply state law when resolving child 
custody issues.  This would normally be true for most Indi-
ans, too.  Today, Indians are citizens of the United States; 
the vast majority of them do not live on any reservation or
Indian lands, but live (as most citizens) on lands that are 
wholly within a State’s jurisdiction.  See ch. 233, 43 Stat. 
253; Dept. of Health and Human Services, Office of Minor-
ity  Health,  Profile:  American  Indian/Alaska  Native  (Feb.
24, 
https://minorityhealth.hhs.gov/omh/browse
.aspx?lvl=3&lvlid=62 (87% live off Indian lands).  Thus, one 
might expect that when a child custody issue regarding an
Indian child arises in a state court, that court would apply 
the same laws that it would for any other citizen. 

2023), 

But  ICWA  displaces  the  normal  state  laws  governing
child custody when it comes to only one group of citizens: 
Indian children.  ICWA defines “Indian child” capaciously:
It includes not only children who are members of an Indian
tribe,  but  also  those  children  who  are  merely  eligible  for 
membership in a tribe and are the biological child of a tribal