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Page Number: 8

4 

MISSOURI v. MCNEELY 

Opinion of the Court 

74.  Finding that this was “unquestionably a routine DWI 
case”  in  which  no  factors  other  than  the  natural  dissi­
pation of blood-alcohol suggested that there was an emer­
gency,  the  court  held  that  the  nonconsensual warrantless 
blood  draw  violated  McNeely’s  Fourth  Amendment  right 
to  be  free  from  unreasonable  searches  of  his  person.    Id., 
at 74–75. 

We  granted  certiorari  to  resolve  a  split  of  authority  on
the question whether the natural dissipation of alcohol in 
the bloodstream establishes a per se exigency that suffices
on  its  own  to  justify  an  exception  to  the  warrant  require­
ment  for  nonconsensual  blood  testing  in  drunk-driving 
investigations.2  See 567 U. S. ___ (2012).  We now affirm. 

II
 
A 

The  Fourth  Amendment  provides  in  relevant  part  that
“[t]he  right  of  the  people  to  be  secure  in  their  persons, 
houses, papers, and effects, against unreasonable searches
and seizures, shall not be violated, and no Warrants shall 
issue, but upon probable cause.”  Our cases have held that 
a  warrantless  search  of  the  person  is  reasonable  only  if 
it  falls  within  a  recognized  exception.  See,  e.g.,  United 
States v. Robinson, 414 U. S. 218, 224 (1973).  That prin­
ciple  applies  to  the  type  of  search  at  issue  in  this  case, 
which  involved  a  compelled  physical  intrusion  beneath 
McNeely’s skin and into his veins to obtain a sample of his 
blood for use as evidence in a criminal investigation.  Such 
an  invasion  of  bodily  integrity  implicates  an  individual’s 

—————— 

2 Compare 358 S. W. 3d 65 (2012) (case below), State v. Johnson, 744 
N. W.  2d  340  (Iowa  2008)  (same  conclusion),  and  State  v.  Rodriguez, 
2007 UT 15, 156 P. 3d 771 (same), with State v. Shriner, 751 N. W. 2d 
538 (Minn. 2008) (holding that the natural dissipation of blood-alcohol
evidence alone constitutes a per se exigency), State v. Bohling, 173 Wis. 
2d  529,  494  N. W.  2d  399  (1993)  (same);  State  v.  Woolery,  116  Idaho 
368, 775 P. 2d 1210 (1989) (same).