Document ID: ./input/supremecourt_opinions/opinions/21pdf/21-954_7l48.pdf
Page Number: 27.0

22 

BIDEN v. TEXAS 

Opinion of the Court 

(slip op., at 14–15).  And because the then-Secretary’s rea-
soning had “little relationship to that of her predecessor,”
the  Court  characterized  the  new  explanations  as  “imper-
missible  post hoc  rationalizations  . . .  not  properly  before
us.”  Id., at ___ (slip op., at 15). 

The  prohibition  on  post hoc  rationalization  applies  only
when the agency proceeds by the first option from Regents. 
Under that circumstance, because the agency has chosen to
“rest on [its original action] while elaborating on its prior
reasoning,” id., at ___ (slip op., at 14), the bar on post hoc
rationalization operates to ensure that the agency’s supple-
mental  explanation  is  anchored  to  “the  grounds  that  the
agency invoked when it took the action,” Michigan v. EPA, 
576 U. S. 743, 758 (2015).  By contrast, as noted above, the
Secretary here chose the second option from Regents, and 
“ ‘deal[t] with the problem afresh’ by taking new agency ac-
tion.”  591 U. S., at ___ (slip op., at 14).  That second option 
can  be  more  procedurally  onerous  than  the  first—the
agency “must comply with the procedural requirements for
new  agency  action”—but  the  benefit  is  that  the  agency  is
“not limited to its prior reasons” in justifying its decision. 
Ibid.  Indeed, the entire purpose of the October 29 Memo-
randa was for the Secretary to “issue a new rescission bol-
stered by new reasons absent from the [June 1] Memoran-
dum,”  ibid.—reasons  that  he  hoped  would  answer  the
District Court’s concerns from the first go-round.  Having
returned to the drawing table and taken new action, there-
fore, the Secretary was not subject to the charge of post hoc
rationalization. 

Third, respondents invoke our decision in Department of 
Commerce  v.  New  York,  588  U. S.  ___  (2019),  to  contend 
that DHS’s failure to “hew[ ] to the administrative straight 
and narrow” deprives the October 29 Memoranda of the pre-
sumption of regularity that normally attends agency action,
Brief for Respondents 43.  As we explained in that case, “in
reviewing  agency  action,  a  court  is  ordinarily  limited  to