Document ID: ./input/supremecourt_opinions/opinions/18pdf/17-1011_mkhn.pdf
Page Number: 12

Cite as:  586 U. S. ____ (2019) 

9 

Opinion of the Court 

assume,  “absent  a  clearly  expressed  legislative  intention 
to the contrary,” that “the legislative purpose is expressed 
by  the  ordinary  meaning  of  the  words  used.”  American 
Tobacco  Co.  v.  Patterson,  456  U. S.  63,  68  (1982)  (altera-
tions omitted).  Whatever the ultimate purpose of interna-
tional  organization  immunity  may  be—the  IOIA  does  not 
address  that  question—the  immediate  purpose  of  the
immunity  provision  is  expressed  in  language  that  Con-
gress typically uses to make one thing continuously equiv-
alent to another. 

B 
The more natural reading of the IOIA is confirmed by a
canon of statutory interpretation that was well established
when  the  IOIA  was  drafted.    According  to  the  “reference” 
canon,  when  a  statute  refers  to  a  general  subject,  the
statute adopts the law on that subject as it exists whenever
a  question  under  the  statute  arises.  2  J.  Sutherland, 
Statutory  Construction  §§5207–5208  (3d  ed.  1943).    For 
example, a statute allowing a company to “collect the same
tolls  and  enjoy  the  same  privileges”  as  other  companies
incorporates  the  law  governing  tolls  and  privileges  as  it
exists at any given moment.  Snell v. Chicago, 133 Ill. 413, 
437–439,  24  N. E.  532,  537  (1890).    In  contrast,  a  statute 
that  refers  to  another  statute  by  specific  title  or  section 
number in effect cuts and pastes the referenced statute as
it existed when the referring statute was enacted, without 
any  subsequent  amendments.    See,  e.g.,  Culver  v.  People 
ex rel. Kochersperger, 161 Ill. 89, 95–99, 43 N. E. 812, 814– 
815  (1896)  (tax-assessment  statute  referring  to  specific 
article  of  another  statute  does  not  adopt  subsequent
amendments to that article).

Federal courts have often relied on the reference canon, 
explicitly  or  implicitly,  to  harmonize  a  statute  with  an 
external  body  of  law  that  the  statute  refers  to  generally.
Thus, for instance, a statute that exempts from disclosure