Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-402_h315.pdf
Page Number: 13.0

Cite as:  585 U. S. ____ (2018) 

9 

Opinion of the Court 

SOTOMAYOR, J.).2 

In a second set of decisions, the Court has drawn a line 
between  what  a  person  keeps  to  himself  and  what  he 
shares with others.  We have previously held that “a per-
son has no legitimate expectation of privacy in information 
he  voluntarily  turns  over  to  third  parties.”    Smith,  442 
U. S.,  at  743–744.    That  remains  true  “even  if  the  infor-
mation is revealed on the assumption that it will be used 
only  for  a  limited  purpose.”  United  States  v.  Miller,  425 
U. S.  435,  443  (1976).  As  a  result,  the  Government  is 
typically free to obtain such information from the recipient
without triggering Fourth Amendment protections. 

This  third-party  doctrine  largely  traces  its  roots  to 
Miller.    While  investigating  Miller  for  tax  evasion,  the 
Government  subpoenaed  his  banks,  seeking  several 
months  of  canceled  checks,  deposit  slips,  and  monthly 
statements.  The  Court  rejected  a  Fourth  Amendment
challenge  to  the  records  collection.  For  one,  Miller  could 
“assert  neither  ownership  nor  possession”  of  the  docu-
ments;  they  were  “business  records  of  the  banks.”  Id., at 
440.  For  another,  the  nature  of  those  records  confirmed 
Miller’s limited expectation of privacy, because the checks
were  “not  confidential  communications  but  negotiable
instruments  to  be  used  in  commercial  transactions,”  and 
the  bank  statements  contained  information  “exposed  to 

—————— 

2 JUSTICE  KENNEDY  argues  that  this  case  is  in  a  different  category  
from Jones and the dragnet-type practices posited in Knotts because the 
disclosure of the cell-site records was subject to “judicial authorization.” 
Post, at 14–16.  That line of argument conflates the threshold question
whether  a  “search”  has  occurred  with  the  separate  matter  of  whether 
the  search  was  reasonable.    The  subpoena  process  set  forth  in  the
Stored  Communications  Act  does  not  determine  a  target’s  expectation
of  privacy.  And  in  any  event,  neither  Jones  nor  Knotts  purported  to
resolve the question of what authorization may be required to conduct
such  electronic  surveillance  techniques.    But  see  Jones,  565  U. S.,  at 
430  (ALITO,  J.,  concurring  in  judgment)  (indicating  that  longer  term 
GPS tracking may require a warrant).