Document ID: ./input/supremecourt_opinions/opinions/08pdf/07-588.pdf/07-588.pdf
Page Number: 33.0

4 

ENTERGY CORP. v. RIVERKEEPER, INC. 

STEVENS, J., dissenting 

agency’s approach to regulation.  Congress, we have noted, 
“does  not  alter  the  fundamental  details  of  a  regulatory
scheme  in  vague  terms  or  ancillary  provisions—it  does
not, one might say, hide elephants in mouseholes.”  Whit-
man  v.  American  Trucking  Assns.,  Inc.,  531  U. S.  457, 
467–468 (2001).

When interpreting statutory silence in the past, we have
sought  guidance  from  a  statute’s  other  provisions.    Evi-
dence that Congress confronted an issue in some parts of a
statute,  while  leaving  it  unaddressed  in  others,  can  dem-
onstrate  that  Congress  meant  its  silence  to  be  decisive.
We  concluded  as  much  in  American  Trucking.    In  that  
case, the Court reviewed the EPA’s claim that §109 of the 
Clean  Air  Act  (CAA),  42  U. S. C.  §7409(a)  (2000  ed.),  au-
thorized  the  Agency  to  consider  implementation  costs  in 
setting  ambient  air  quality  standards.    We  read  §109,
which  was  silent  on  the  matter,  to  prohibit  Agency  reli-
ance on cost considerations.  After examining other provi-
sions in which Congress had given the Agency authority to
consider  costs,  the  Court  “refused  to  find  implicit  in  am-
biguous  sections  of  the  CAA  an  authorization  to  consider 
costs  that  has  elsewhere,  and  so  often,  been  expressly 
granted.”  531  U. S.,  at  467.    Studied  silence,  we  thus 
concluded,  can  be  as  much  a  prohibition  as  an  explicit
“no.” 

Further motivating the Court in American Trucking was 
the  fact  that  incorporating  implementation  costs  into  the 
Agency’s  calculus  risked  countermanding  Congress’  deci-
sion to protect public health.  The cost of implementation,
we said, “is both so indirectly related to public health and 
so  full  of  potential  for  canceling  the  conclusions  drawn 
from  direct  health  effects  that  it  would  surely  have  been
expressly mentioned in [the text] had Congress meant it to 
be considered.”  Id., at 469. 

American  Trucking’s  approach  should  have  guided  the
Court’s reading of §316(b).  Nowhere in the text of §316(b)