Document ID: ./input/supremecourt_opinions/opinions/17pdf/17-494_j4el.pdf
Page Number: 10.0

Cite as:  585 U. S. ____ (2018) 

5 

Opinion of the Court 

II 
The  Constitution  grants  Congress  the  power  “[t]o  regu­
late  Commerce  . . .  among  the  several  States.”  Art. I,  §8, 
cl. 3.  The Commerce Clause “reflect[s] a central concern of 
the Framers that was an immediate reason for calling the
Constitutional Convention: the conviction that in order to 
succeed,  the  new  Union  would  have  to  avoid  the  tenden­
cies  toward  economic  Balkanization  that  had  plagued 
relations  among  the  Colonies  and  later  among  the  States
under  the  Articles  of  Confederation.”  Hughes  v.  Oklaho-
ma,  441  U. S.  322,  325–326  (1979).    Although  the  Com­
merce Clause is written as an affirmative grant of authority 
to  Congress,  this  Court  has  long  held  that  in  some
instances  it  imposes  limitations  on  the  States  absent 
congressional action.  Of course, when Congress exercises
its power to regulate commerce by enacting legislation, the 
legislation controls.  Southern Pacific Co. v. Arizona ex rel. 
Sullivan,  325  U. S.  761,  769  (1945).    But  this  Court  has 
observed that “in general Congress has left it to the courts
to formulate the rules” to preserve “the free flow of inter­
state commerce.”  Id., at 770. 

To  understand  the  issue  presented  in  this  case,  it  is 
instructive first to survey the general development of this
Court’s  Commerce  Clause  principles  and  then  to  review 
the application of those principles to state taxes. 

A 
From early in its history, a central function of this Court
has been to adjudicate disputes that require interpretation 
of  the  Commerce  Clause  in  order  to  determine  its  mean­
ing, its reach, and the extent to which it limits state regu­
lations of commerce.  Gibbons v. Ogden, 9 Wheat. 1 (1824),
began setting the course by defining the meaning of com­
merce.  Chief  Justice  Marshall  explained  that  commerce 
included both “the interchange of commodities” and “com­
mercial intercourse.”  Id., at 189, 193.  A concurring opin­