Document ID: ./input/supremecourt_opinions/opinions/13pdf/12-158_6579.pdf
Page Number: 44

Cite as:  572 U. S. ____ (2014) 

3 

THOMAS, J., concurring in judgment 

in our constitutional structure.  Although the parties have 
not  challenged  the  constitutionality  of  the  particular
treaty  at  issue  here,  in  an  appropriate  case  I  believe  the 
Court  should  address  the  scope  of  the  Treaty  Power  as  it
was  originally  understood.  Today,  it  is  enough  to  high-
light  some  of  the  structural  and  historical  evidence  sug-
gesting  that  the  Treaty  Power  can  be  used  to  arrange 
intercourse with other nations, but not to regulate purely
domestic affairs. 

I 

The Treaty Power was not drafted on a blank slate.  To 
the contrary, centuries of experience—reflected in treatises, 
dictionaries,  and  actual  practice—shaped  the  contours  of
that power.

Early treatises discussed a wide variety of treaties that
nevertheless  shared  a  common  thread:  All  of  them  gov-
erned genuinely international matters such as war, peace, 
and  trade  between  nations.    See,  e.g.,  2  H.  Grotius,  De 
Jure  Belli  Ac  Pacis  394–396  (1646  ed.,  F.  Kelsey  transl. 
1925) (treaties are made “for the sake either of peace or of 
some  alliance,”  including  “for  the  restoration  of  captives
and  of  captured  property,  and  for  safety”;  “that  neither 
signatory  shall  have  fortresses  in  the  territory  of  the
other,  or  defend  the  subjects  of  the  other,  or  furnish  a
passage  to  the  enemy  of  the  other”;  and  for  “commercial
relations”  and  agreements  on  “import  duties”  (footnote 
omitted));  2  S.  Pufendorf,  De  Jure  Naturae  et  Gentium 
1331 (1688 ed., C. Oldfather & W. Oldfather transls. 1934) 
(treaties are made “to form some union or society, the end 
of  which  is  either  commercial  relations,  or  a  united  front 
in war”); 3 E. Vattel, The Law of Nations 165 (1758 ed., C. 
Fenwick  transl.  1916)  (treaties,  which  “can  be  subdivided 
into as many classes as there are varieties in the character 
of  national  relations,”  “deal  with  conditions  of  commerce, 
with  mutual  defense,  with  belligerent  relations,  with