Document ID: ./input/supremecourt_opinions/opinions/21pdf/20-601_bq7c.pdf
Page Number: 11

Cite as:  595 U. S. ____ (2022) 

7 

Opinion of the Court 

appellate review concluded.  See id., at 30 (judgment bind-
ing on attorney general’s office “subject to any modification, 
reversal or vacation of the judgment on appeal”). 
  For  these  reasons,  we  refuse  to  adopt  a  categorical 
claims-processing rule that bars consideration of the attor-
ney general’s motion.  In doing so, we do not attempt to set 
out a general rule governing the right of non-parties to ap-
peal or to move for appellate intervention. 

III 
  Having  concluded  that  neither  a  jurisdictional  require-
ment  nor  a  mandatory  claims-processing  rule  barred  con-
sideration of the attorney general’s motion, we turn to the 
question whether the Court of Appeals properly denied that 
motion.  No statute or rule provides a general standard to 
apply in deciding whether intervention on appeal should be 
allowed.   The  Federal Rules  of  Appellate  Procedure  make 
only one passing reference to intervention, and that refer-
ence concerns the review of agency action.  See Rule 15(d); 
Amalgamated  Transit  Union  Int’l,  AFL–CIO  v.  Donovan, 
771 F. 2d 1551, 1553, n. 3 (CADC 1985).  Without any rule 
that  governs  appellate  intervention,  we  have  looked  else-
where for guidance.  Thus we have considered the “policies 
underlying intervention” in the district courts, Automobile 
Workers v. Scofield, 382 U. S. 205, 217, n. 10 (1965), includ-
ing  the  legal  “interest”  that  a  party  seeks  to  “protect” 
through  intervention  on  appeal.    Fed.  Rule  Civ.  Proc. 
24(a)(2). 

A 
  In defending the Kentucky law, the attorney general as-
serts a substantial legal interest that sounds in deeper, con-
stitutional considerations.  As we have observed, our Con-
stitution “ ‘spli[t] the atom of sovereignty.’ ”  Alden v. Maine, 
527 U. S. 706, 751 (1999) (quoting Saenz v. Roe, 526 U. S. 
489, 504, n. 17 (1999)).  “The Constitution limited but did