Document ID: ./input/supremecourt_opinions/opinions/19pdf/18-9526_9okb.pdf
Page Number: 42.0

Cite as:  591 U. S. ____ (2020) 

39 

Opinion of the Court 

tribal  members  for  major  crimes.  All  our  decision  today
does  is  vindicate  that  replacement  promise.  And  if  the 
threat of unsettling convictions cannot save a precedent of
this Court, see Ramos v. Louisiana, 590 U. S. ___, ___–___ 
(2020)  (plurality  opinion)  (slip  op.,  at  23–26),  it  certainly
cannot force us to ignore a statutory promise when no prec-
edent stands before us at all. 

What’s more, a decision for either  party today risks up-
setting some convictions.  Accepting the State’s argument
that the MCA never applied in Oklahoma would preserve 
the  state-court  convictions  of  people  like  Mr.  McGirt,  but 
simultaneously  call  into  question  every  federal  conviction 
obtained for crimes committed on trust lands and restricted 
Indian allotments since Oklahoma recognized its jurisdic-
tional error more than 30 years ago.  See supra, at 22.  It’s 
a consequence of their own arguments that Oklahoma and 
the dissent choose to ignore, but one which cannot help but 
illustrate the difficulty of trying to guess how a ruling one 
way or the other might affect past cases rather than simply 
proceeding to apply the law as written. 

Looking  to  the  future,  Oklahoma  warns  of  the  burdens 
federal and tribal courts will experience with a wider juris-
diction and increased caseload.  But, again, for every juris-
dictional  reaction  there  seems  to  be  an  opposite  reaction: 
recognizing that  cases like Mr. McGirt’s belong in federal
court  simultaneously  takes  them  out  of  state  court.    So 
while  the  federal  prosecutors  might  be  initially  under-
staffed  and  Oklahoma  prosecutors  initially  overstaffed,  it 
doesn’t  take  a  lot  of  imagination  to  see  how  things  could 
work out in the end. 

Finally, the State worries that our decision will have sig-
nificant consequences for civil and regulatory law.  The only
question before us, however, concerns the statutory defini-
tion of “Indian country” as it applies in federal criminal law 
under the MCA, and often nothing requires other civil stat-