Document ID: ./input/supremecourt_opinions/opinions/19pdf/19-715_febh.pdf
Page Number: 17.0

12 

TRUMP v. MAZARS USA, LLP 

Opinion of the Court 

U. S. 155, 161 (1955); it must “concern[ ] a subject on which
legislation ‘could be had,’ ” Eastland v. United States Ser-
vicemen’s  Fund,  421  U. S.  491,  506  (1975)  (quoting 
McGrain, 273 U. S., at 177). 

Furthermore, Congress may not issue a subpoena for the
purpose of “law enforcement,” because “those powers are as-
signed under our Constitution to the Executive and the Ju-
diciary.”  Quinn, 349 U. S., at 161.  Thus Congress may not 
use  subpoenas  to  “try”  someone  “before  [a]  committee  for 
any  crime  or  wrongdoing.”    McGrain,  273  U. S.,  at  179. 
Congress has no “ ‘general’ power to inquire into private af-
fairs and compel disclosures,” id., at 173–174, and “there is 
no congressional power to expose for the sake of exposure,” 
Watkins, 354 U. S., at 200.  “Investigations conducted solely
for the personal aggrandizement of the investigators or to
‘punish’ those investigated are indefensible.”  Id., at 187. 

Finally,  recipients  of  legislative  subpoenas  retain  their 
constitutional rights throughout the course of an investiga-
tion.  See id., at 188, 198.  And recipients have long been
understood to retain common law and constitutional privi-
leges  with  respect  to  certain  materials,  such  as  attorney-
client communications and governmental communications 
protected  by  executive  privilege.  See,  e.g.,  Congressional 
Research  Service,  supra,  at  16–18  (attorney-client  privi-
lege); Senate Select Committee, 498 F. 2d, at 727, 730–731 
(executive privilege). 

C 
The President contends, as does the Solicitor General ap-
pearing on behalf of the United States, that the usual rules 
for congressional subpoenas do not govern here because the
President’s papers are at issue.  They argue for a more de-
manding  standard  based  in  large  part  on  cases  involving 
the  Nixon  tapes—recordings  of  conversations  between 
President Nixon and close advisers discussing the break-in 
at  the  Democratic  National  Committee’s  headquarters  at