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Page Number: 26.0

22 

MISSOURI v. MCNEELY 

Opinion of the Court 

requirement.  See Pet. for Cert. i. 

Here  and  in  its  own  courts  the  State  based  its  case  on 

an insistence that a driver who declines to submit to test­
ing after being arrested for driving under the influence of 
alcohol  is  always  subject  to  a  nonconsensual  blood  test 
without any precondition for a warrant.  That is incorrect. 
Although  the  Missouri  Supreme  Court  referred  to  this 
case  as  “unquestionably  a  routine  DWI  case,”  358  S. W.
3d,  at  74,  the  fact  that  a  particular  drunk-driving  stop  is 
“routine”  in  the  sense  that  it  does  not  involve  “ ‘special 
facts,’ ” ibid., such as the need for the police to attend to a 
car accident, does not mean a warrant is required.  Other 
factors  present  in  an  ordinary  traffic  stop,  such  as  the
procedures  in  place  for  obtaining  a  warrant  or  the  avail­
ability of a magistrate judge, may affect whether the police 
can obtain a warrant in an expeditious way and therefore
may  establish  an  exigency  that  permits  a  warrantless
search.  The  relevant  factors  in  determining  whether  a 
warrantless  search  is  reasonable,  including  the  practical 
problems  of  obtaining  a  warrant  within  a  timeframe  that 
still preserves the opportunity to obtain reliable evidence, 
will  no  doubt  vary  depending  upon  the  circumstances  in
the case. 

Because  this  case  was  argued  on  the  broad  proposition 
that  drunk-driving  cases  present  a  per se  exigency,  the
arguments  and  the  record  do  not  provide  the  Court  with 
an  adequate  analytic  framework  for  a  detailed  discussion
of all the relevant factors that can be taken into account in 
determining  the  reasonableness  of  acting  without  a  war­
rant.  It  suffices  to  say  that  the  metabolization  of  alcohol 
in  the  bloodstream  and  the  ensuing  loss  of  evidence  are
among  the  factors  that  must  be  considered  in  deciding
whether a warrant is required.  No doubt, given the large
number of arrests for this offense in different jurisdictions
nationwide,  cases  will  arise  when  anticipated  delays  in
obtaining a warrant  will justify a blood test without judi­