Document ID: ./input/supremecourt_opinions/opinions/17pdf/16-402_h315.pdf
Page Number: 41

14 

CARPENTER v. UNITED STATES 

KENNEDY, J., dissenting 

requires  a  warrant  simply  did  not  occur  when  the  Gov-
ernment  used  court-approved  compulsory  process,  based
on a finding of reasonable necessity, to compel a cell phone 
service provider, as owner, to disclose cell-site records. 

III 
The Court rejects a straightforward application of Miller 
and Smith.  It concludes instead that applying those cases
to cell-site records would work a “significant extension” of 
the principles underlying them, ante, at 15, and holds that 
the  acquisition  of  more  than  six  days  of  cell-site  records
constitutes a search, ante, at 11, n. 3. 

In my respectful view the majority opinion misreads this
Court’s  precedents,  old  and  recent,  and  transforms  Miller 
and Smith into an unprincipled and unworkable doctrine.
The  Court’s  newly  conceived  constitutional  standard  will 
cause confusion; will undermine traditional and important 
law enforcement practices; and will allow the cell phone to
become  a  protected  medium  that  dangerous  persons  will 
use to commit serious crimes. 

A 
The  Court  errs  at  the  outset  by  attempting  to  sidestep 
Miller and Smith.  The Court frames this case as following 
instead from United States v. Knotts, 460 U. S. 276 (1983), 
and  United  States  v.  Jones,  565  U. S.  400  (2012).    Those 
cases, the Court suggests, establish that “individuals have 
a  reasonable  expectation  of  privacy  in  the  whole  of  their 
physical movements.”  Ante, at 79, 12. 

Knotts held just the opposite: “A person traveling in an
automobile  on  public  thoroughfares  has  no  reasonable 
expectation of privacy in his movements from one place to
another.”  460 U. S., at 281.  True, the Court in Knotts also 
suggested  that  “different  constitutional  principles  may  be 
applicable”  to  “dragnet-type  law  enforcement  practices.” 
Id., at 284.  But by dragnet practices the Court was refer-