Document ID: ./input/supremecourt_opinions/opinions/21pdf/21-954_7l48.pdf
Page Number: 20

Cite as:  597 U. S. ____ (2022) 

15 

Opinion of the Court 

detained’  means  ‘shall  be  detained,’ ”  post,  at  9,  and  criti-
cizes  the  Government’s  “argument  that  ‘shall’  means 
‘may,’ ” post, at 10.  But the theory works both ways.  Con-
gress conferred contiguous-territory return authority in ex-
pressly  discretionary  terms. 
“ ‘[M]ay  return  the  alien’ 
means  ‘may  return  the  alien.’ ”  The  desire  to  redress  the 
Government’s  purported  violation  of  section  1225(b)(2)(A) 
does  not  justify  transforming  the  nature  of  the  authority
conferred by section 1225(b)(2)(C).6 

The historical context in which the provision was adopted
confirms the plain import of its text.  See, e.g., Niz-Chavez 
v. Garland, 593 U. S. ___, ___ (2021) (slip op., at 9) (textual
analysis confirmed by “a wider look at [the statute’s] struc-
ture and history”).  Section 1225(b)(2)(C) was not added to 
the  statute  until  1996, in  the  Illegal  Immigration  Reform
and Immigrant Responsibility Act of 1996 (IIRIRA), §302, 
110 Stat. 300–583—more than 90 years after the Immigra-
tion Act of 1903 added the “shall be detained” language that 
appears in section 1225(b)(2)(A).  And section 1225(b)(2)(C)
was enacted in the immediate aftermath of a Board of Im-
migration  Appeals  (BIA)  decision  that  specifically  called 
into question the legality of the contiguous-territory return
practice.  Prior to that decision, the longstanding practice
of  the  Immigration  and  Naturalization  Service  (INS)  had 
been to require some aliens arriving at land border ports of 

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6 In arguing that the Court should do so, the dissent proposes a number 
of hypotheticals in which a party fails to comply with a legal obligation 
imposed by statute and additionally refuses to exercise a discretionary 
alternative authorized by that statute.  Post, at 12–13 (ALITO, J., dissent-
ing).  We wholeheartedly endorse the conclusion that the dissent draws 
from these hypotheticals: that “the failure to make use of the discretion-
ary option would not be seen as a valid excuse for non-compliance with 
the command that certain conduct ‘shall’ be performed.”  Post, at 13.  But 
the  question  before  us  is  not  whether  the  Government  is  violating  the 
immigration laws generally.  The question is whether the INA requires
the government to continue implementing MPP.  And the statutory text 
clearly answers that question in the negative.