Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-402_h315.pdf
Page Number: 52

2 

CARPENTER v. UNITED STATES 

THOMAS, J., dissenting 

The  more  fundamental  problem  with  the  Court’s  opin­
ion,  however,  is  its  use  of  the  “reasonable  expectation  of 
privacy”  test,  which  was  first  articulated  by  Justice  Har­
lan in Katz v. United States, 389 U. S. 347, 360–361 (1967) 
(concurring  opinion).  The  Katz  test  has  no  basis  in  the 
text or history of the Fourth Amendment.  And, it invites 
courts to make judgments about policy, not law.  Until we 
confront the problems with this test, Katz will continue to 
distort  Fourth  Amendment  jurisprudence.    I  respectfully
dissent. 

I 
Katz was the culmination of a series of decisions apply­
ing  the  Fourth  Amendment  to  electronic  eavesdropping. 
The first such decision was Olmstead v. United States, 277 
U. S. 438 (1928), where federal officers had intercepted the
defendants’ conversations by tapping telephone lines near 
their  homes.  Id.,  at  456–457.    In  an  opinion  by  Chief 
Justice Taft, the Court concluded that this wiretap did not 
violate  the  Fourth  Amendment.    No  “search”  occurred, 
according to the Court, because the officers did not physi­
cally  enter  the  defendants’  homes.  Id.,  at  464–466.    And 
neither the telephone lines nor the defendants’ intangible 
conversations  qualified  as  “persons,  houses,  papers,  [or] 
effects”  within  the  meaning  of  the  Fourth  Amendment. 
Ibid.1    In  the  ensuing  decades,  this  Court  adhered  to 

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1 Justice  Brandeis  authored  the  principal  dissent  in  Olmstead.  He 
consulted  the  “underlying  purpose,”  rather  than  “the  words  of  the 
[Fourth] Amendment,” to conclude that the wiretap was a search.  277 
U. S.,  at  476.    In  Justice  Brandeis’  view,  the  Framers  “recognized  the
significance  of  man’s  spiritual  nature,  of  his  feelings  and  of  his  intel­
lect”  and  “sought  to  protect Americans  in  their  beliefs,  their  thoughts, 
their emotions and their sensations.”  Id., at 478.  Thus, “every unjusti­
fiable intrusion by the Government upon the privacy of the individual, 
whatever  the  means  employed,”  should  constitute  an  unreasonable 
search under the Fourth Amendment.  Ibid.