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Page Number: 64.0

8 

WEST VIRGINIA v. EPA 

KAGAN, J., dissenting 

coordinated method; a procedure.”  American Heritage Dic-
tionary 1768 (5th ed. 2018).  The majority complains that a
similar definition—cited to the Solicitor General’s brief but 
originally from another dictionary—is just too darn broad. 
Ante,  at  28;  see  Brief  for  United  States  31  (quoting  Web-
ster’s  New  International  Dictionary  2562  (2d  ed.  1959)). 
“[A]lmost anything” capable of reducing emissions, the ma-
jority  says,  “could  constitute  such  a  ‘system’ ”  of  emission 
reduction.  Ante, at 28.  But that is rather the point.  Con-
gress used an obviously broad word (though surrounding it 
with constraints, see supra, at 7) to give EPA lots of latitude
in deciding how to set emissions limits.  And contra the ma-
jority, a broad term is not the same thing as a “vague” one. 
Ante, at 18, 20, 28.  A broad term is comprehensive, exten-
sive, wide-ranging; a “vague” term is unclear, ambiguous,
hazy.  (Once again, dictionaries would tell the tale.)  So EPA 
was quite right in stating in the Clean Power Plan that the 
“[p]lain meaning” of the term “system” in Section 111 refers
to  “a  set  of  measures  that  work  together  to  reduce  emis-
sions.”  80 Fed. Reg. 64762.  Another of this Court’s opin-
ions, involving a matter other than the bogeyman of envi-
ronmental regulation, might have stopped there. 

For  generation  shifting  fits  comfortably  within  the  con-
ventional  meaning  of  a  “system  of  emission  reduction.” 
Consider one of the most common mechanisms of genera-
tion  shifting:  the  use  of  a  cap-and-trade  scheme.  Here  is 
how  the  majority  describes  cap  and  trade:  “Under  such  a 
scheme, sources that receive a reduction in their emissions 
can sell a credit representing the value of that reduction to
others, who are able to count it toward their own applicable 
emissions caps.”  Ante, at 8–9.  Does that sound like a “sys-
tem” to you?  It does to me too.  And it also has to this Court. 
In the past, we have explained that “[t]his type of ‘cap-and-
trade’ system cuts costs while still reducing pollution to tar-
get levels.”  EPA v. EME Homer City Generation, L. P., 572 
U. S. 489, 503, n. 10 (2014) (emphasis added).  So what does