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Page Number: 8.0

2 

MASSACHUSETTS v. EPA 

Opinion of the Court 

petition  for  certiorari  that  the  Environmental  Protection
Agency  (EPA)  has  abdicated  its  responsibility  under  the 
Clean Air Act to regulate the emissions of four greenhouse 
gases,  including  carbon  dioxide.  Specifically,  petitioners
asked us to answer two questions concerning the meaning
of  §202(a)(1)  of  the  Act:  whether  EPA  has  the  statutory 
authority  to  regulate  greenhouse  gas  emissions  from  new 
motor  vehicles;  and  if  so,  whether  its  stated  reasons  for 
refusing to do so are consistent with the statute. 

In  response,  EPA,  supported  by  10  intervening  States5 
and  six  trade  associations,6  correctly  argued  that  we  may
not  address  those  two  questions  unless  at  least  one  peti-
tioner  has  standing  to  invoke  our  jurisdiction  under  Arti-
cle  III  of  the  Constitution.    Notwithstanding  the  serious
character of that jurisdictional argument and the absence 
of  any  conflicting  decisions  construing  §202(a)(1),  the
unusual importance of the underlying issue persuaded us 
to grant the writ.  548 U. S. __ (2006). 

I 

Section 202(a)(1) of the Clean  Air Act, as added by Pub. 
L. 89–272, §101(8), 79 Stat. 992, and as amended by, inter 
alia, 84 Stat. 1690 and 91 Stat. 791, 42 U. S. C. §7521(a)(1), 
provides: 

“The  [EPA]  Administrator  shall  by  regulation  pre-
scribe  (and  from  time  to  time  revise)  in  accordance
with the provisions of this section, standards applica-
ble to the emission of any air pollutant from any class 
or classes of new motor vehicles or new motor vehicle 
engines,  which  in  his  judgment  cause,  or  contribute
to, air pollution which may reasonably be anticipated 

—————— 

5 Alaska,  Idaho,  Kansas,  Michigan,  Nebraska,  North  Dakota,  Ohio, 

South Dakota, Texas, and Utah. 

6 Alliance of Automobile Manufacturers, National Automobile Dealers 
Association,  Engine  Manufacturers  Association,  Truck  Manufacturers
Association, CO2 Litigation Group, and Utility Air Regulatory Group.