Document ID: ./input/supremecourt_opinions/opinions/22pdf/21-376_7l48.pdf
Page Number: 126.0

4 

HAALAND v. BRACKEEN 

ALITO, J., dissenting 

said.  See, e.g., Delaware Tribal Business Comm. v. Weeks, 
430 U. S. 73, 84 (1977) (quoting United States v. Alcea Band 
of Tillamooks, 329 U. S. 40, 54 (1946) (plurality opinion)). 
But the formulation’s pedigree cannot make up for its vacu-
ity.  The term “plenary” is defined in one dictionary after 
another as “absolute.”  See, e.g., New Oxford American Dic-
tionary 1343 (3d ed. 2010); Webster’s Third New Interna-
tional Dictionary 1739 (2002); The Random House Diction-
ary  of  the  English  Language  1486  (2d  ed.  1987).    If  we 
accept these definitions, what the Court says is that abso-
lute ≠ absolute and plenary ≠ plenary, violating one of the 
most basic laws of logic.  Surely we can do better than that.
We need not map the outer bounds of Congress’s Indian
affairs authority to hold that  the  challenged provisions of
ICWA lie outside it.  We need only acknowledge that even 
so-called plenary powers cannot override foundational con-
stitutional constraints.  By attempting to control state judi-
cial proceedings in a field long-recognized to be the virtually 
exclusive province of the States, ICWA violates the funda-
mental structure of our constitutional order. 

In reaching this conclusion, I do not question the propo-
sition that Congress has broad power to regulate Indian af-
fairs.  We have “consistently described” Congress’s “powers 
to legislate in respect to Indian tribes” as “ ‘plenary and ex-
clusive.’ ”  United States v. Lara, 541 U. S. 193, 200 (2004) 
(collecting cases).  Reflecting this understanding, we have 
sanctioned a wide range of enactments that bear on Indian
tribes and their members, sometimes (regrettably) without 
tracing  the  source  of  Congress’s  authority  to  a  particular 
enumerated power.  See, e.g., Santa Clara Pueblo v. Mar-
tinez, 436 U. S. 49, 56–58 (1978) (modifying tribal govern-
ments’ powers of self-government); Lone Wolf v. Hitchcock, 
187  U. S.  553,  565–566  (1903)  (transferring  tribal  land). 
Nor do I dispute the notion that Congress has undertaken
responsibilities that have been roughly analogized to those