Document ID: ./input/supremecourt_opinions/opinions/12pdf/11-1425_cb8e.pdf
Page Number: 9

Cite as:  569 U. S. ____ (2013) 

5 

Opinion of the Court 

“most  personal  and  deep-rooted  expectations  of  privacy.” 
Winston v. Lee, 470 U. S. 753, 760 (1985); see also Skinner 
v.  Railway  Labor  Executives’  Assn.,  489  U. S.  602,  616 
(1989).

We first considered the Fourth Amendment restrictions 
on  such  searches  in  Schmerber,  where,  as  in  this  case,  a 
blood  sample  was  drawn  from  a  defendant  suspected  of 
driving while under the influence of alcohol.  384 U. S., at 
758.  Noting  that  “[s]earch  warrants  are  ordinarily  re­
quired for searches of dwellings,” we reasoned that “absent 
an emergency, no less could be required where intrusions
into the human body are concerned,” even when the search
was conducted following a lawful arrest.  Id., at 770.  We 
explained  that  the  importance  of  requiring  authorization 
by a “ ‘neutral and detached magistrate’ ” before allowing a
law enforcement officer to “invade another’s body in search
of evidence of guilt is indisputable and great.”  Ibid. (quot­
ing Johnson v. United States, 333 U. S. 10, 13–14 (1948)). 
As  noted,  the  warrant  requirement  is  subject  to  ex­
ceptions. 
“One  well-recognized  exception,”  and  the  one
at  issue  in  this  case,  “applies  when  the  exigencies  of  the
situation make the needs of law enforcement so compelling 
that  a  warrantless  search  is  objectively  reasonable  under 
the Fourth Amendment.”  Kentucky v. King, 563 U. S. ___, 
___  (2011)  (slip  op.,  at  6)  (internal  quotation  marks  and 
brackets  omitted).    A  variety  of  circumstances  may  give 
rise  to  an  exigency  sufficient  to  justify  a  warrantless 
search, including law enforcement’s need to provide emer­
gency  assistance  to  an  occupant  of  a  home,  Michigan  v. 
Fisher, 558 U. S. 45, 47–48 (2009) (per curiam), engage in
“hot  pursuit”  of  a  fleeing  suspect,  United  States  v.  San­
tana, 427 U. S. 38, 42–43 (1976), or enter a burning building 
to  put  out  a  fire  and  investigate  its  cause,  Michigan  v. 
Tyler, 436 U. S. 499, 509–510 (1978).  As is relevant here, 
we  have  also  recognized  that  in  some  circumstances  law 
enforcement  officers  may  conduct  a  search  without  a