Document ID: ./input/supremecourt_opinions/opinions/23pdf/22-451_7m58.pdf
Page Number: 25.0

Cite as:  603 U. S. ____ (2024) 

17 

Opinion of the Court 

interpretations issued contemporaneously with the statute 
at  issue,  and  which  have  remained  consistent  over  time, 
may be especially useful in determining the statute’s mean-
ing.  See ibid.; American Trucking Assns., 310 U. S., at 549. 
In  a  case  involving  an  agency,  of  course,  the  statute’s
meaning may well be that the agency is authorized to exer-
cise a degree of discretion.  Congress has often enacted such 
statutes.  For example, some statutes “expressly delegate[ ]” 
to an agency the authority to give meaning to a particular 
statutory  term.  Batterton  v.  Francis,  432  U. S.  416,  425 
(1977) (emphasis deleted).5  Others empower an agency to
prescribe rules to “fill up the details” of a statutory scheme, 
Wayman v. Southard, 10 Wheat. 1, 43 (1825), or to regulate 
subject  to  the  limits  imposed  by  a  term  or  phrase  that
“leaves  agencies  with  flexibility,”  Michigan  v.  EPA,  576 
U. S.  743,  752  (2015),  such  as  “appropriate”  or  “reasona-
ble.”6 

When  the  best  reading  of  a  statute  is  that  it  delegates 

—————— 

5 See,  e.g.,  29  U. S. C.  §213(a)(15)  (exempting  from  provisions  of  the 
Fair Labor Standards Act “any employee employed on a casual basis in
domestic service employment to provide companionship services for in-
dividuals who (because of age or infirmity) are unable to care for them-
selves (as such terms are defined and delimited by regulations of the Sec-
retary)” (emphasis added)); 42 U. S. C. §5846(a)(2) (requiring notification
to Nuclear Regulatory Commission when a facility or activity licensed or 
regulated pursuant to the Atomic Energy Act “contains a defect which 
could create a substantial safety hazard, as defined by regulations which 
the Commission shall promulgate” (emphasis added)). 

6 See, e.g., 33 U. S. C. §1312(a) (requiring establishment of effluent lim-
itations “[w]henever, in the judgment of the [Environmental Protection
Agency (EPA)] Administrator . . . , discharges of pollutants from a point 
source or group of point sources . . . would interfere with the attainment
or maintenance of that water quality . . . which shall assure” various out-
comes, such as the “protection of public health” and “public water sup-
plies”);  42  U. S. C.  §7412(n)(1)(A)  (directing  EPA  to  regulate  power 
plants “if the Administrator finds such regulation is appropriate and nec-
essary”).