Document ID: ./input/supremecourt_opinions/opinions/19pdf/18-556_e1pf.pdf
Page Number: 9

Cite as:  589 U. S. ____ (2020) 

7 

Opinion of the Court 

The dissent reads our cases differently, contending that
they permit an officer to use only the common sense derived 
from his “experiences in law enforcement.”  Post, at 5 (opin-
ion of SOTOMAYOR, J.).  Such a standard defies the “common 
sense”  understanding  of  common  sense,  i.e.,  information 
that is accessible to people generally, not just some special-
ized subset of society.  More importantly, this standard ap-
pears  nowhere  in  our  precedent.    In  fact,  we  have  stated 
that reasonable suspicion is an “abstract” concept that can-
not  be  reduced  to  “a  neat  set  of  legal  rules,”  Arvizu,  534 
U. S.,  at  274  (internal  quotation  marks  omitted),  and  we 
have  repeatedly  rejected  courts’  efforts  to  impose  a  rigid 
structure on the concept of reasonableness, ibid.; Sokolow, 
490 U. S., at 7–8.  This is precisely what the dissent’s rule
would do by insisting that officers must be treated as bifur-
cated persons, completely precluded from drawing factual
inferences  based  on  the  commonly  held  knowledge  they 
have acquired in their everyday lives. 

The dissent’s rule would also impose on police the burden
of pointing to specific training materials or field experiences 
justifying reasonable suspicion for the myriad infractions in 
municipal criminal codes.  And by removing common sense 
as a source of evidence, the dissent would considerably nar-
row the daylight between the showing required for probable 
cause and the “less stringent” showing required for reason-
able  suspicion.  Prouse,  440  U. S.,  at  654;  see  White,  496 
U. S., at 330.  Finally, it would impermissibly tie a traffic 
stop’s  validity  to  the  officer’s  length  of  service.  See 
Devenpeck  v.  Alford,  543  U. S.  146,  154  (2004).    Such  re-
quirements  are  inconsistent  with  our  Fourth  Amendment
jurisprudence, and we decline to adopt them here. 

In reaching this conclusion, we in no way minimize the 
significant  role  that  specialized  training  and  experience 
routinely play in law enforcement investigations.  See, e.g., 
Arvizu,  534  U. S.,  at  273–274.    We  simply  hold  that  such
experience is not required in every instance.