Case Title: State v. Houghton

Citation: 2015 WI 79

Docket Number: 2013AP001581-CR

State: wisconsin

Court: Wisconsin Supreme Court

Date: 2015-07-14T00:00:00Z

Document:
2015 WI 79 
 
SUPREME COURT OF WISCONSIN 
 
 
 
 
 
CASE NO.: 
2013AP1581-CR 
COMPLETE TITLE: 
State of Wisconsin, 
          Plaintiff-Respondent-Petitioner, 
     v. 
Richard E. Houghton, Jr., 
          Defendant-Appellant. 
 
 
 
 
REVIEW OF A DECISION OF THE COURT OF APPEALS 
(Reported at 354 Wis. 2d 623, 848 N.W.2d 904) 
(Ct. App. 2014 – Unpublished) 
 
 
 
OPINION FILED: 
July 14, 2015 
SUBMITTED ON BRIEFS: 
        
ORAL ARGUMENT: 
April 22, 2015 
 
 
SOURCE OF APPEAL: 
 
 
COURT: 
Circuit 
 
COUNTY: 
Walworth 
 
JUDGE: 
John R. Race 
 
 
 
JUSTICES: 
 
 
CONCURRED: 
      
 
DISSENTED: 
ABRAHAMSON, BRADLEY, J.J., dissent. (Opinion 
Filed.) 
 
NOT PARTICIPATING:          
 
 
 
ATTORNEYS: 
 
For the plaintiff-respondent-petitioner, the cause was 
argued by Tiffany M. Winter, assistant attorney general, with 
whom on the briefs was Brad D. Schimel, attorney general. 
 
For the defendant-appellant there was a brief by Andrew R. 
Walter, Elkhorn, and oral argument by Andrew R. Walter. 
 
An amicus curiae brief was filed by Hannah Schieber Jurss, 
assistant state public defender, with whom on the brief was 
Kelli S. Thompson, state public defender, on behalf of the 
Office of the State Public Defender. 
 
 
 
2015 WI 79
NOTICE 
This opinion is subject to further 
editing and modification.  The final 
version will appear in the bound 
volume of the official reports.   
No.  2013AP1581-CR   
(L.C. No. 
2012CF187) 
STATE OF WISCONSIN  
 
 
   : 
IN SUPREME COURT 
 
 
State of Wisconsin, 
 
          Plaintiff-Respondent-Petitioner, 
 
     v. 
 
Richard E. Houghton, Jr., 
 
          Defendant-Appellant. 
 
 
 
FILED 
 
JUL 14, 2015 
 
Diane M. Fremgen 
Clerk of Supreme Court 
 
 
 
 
REVIEW of a decision of the Court of Appeals.  Reversed.   
 
¶1 
DAVID T. PROSSER, J.   This is a review of an 
unpublished decision of the court of appeals,1 which reversed a 
judgment of conviction entered by the Walworth County Circuit 
Court2 against Richard E. Houghton, Jr. (Houghton).  Houghton 
pled guilty to one count of possession of THC (greater than 200 
grams) with intent to deliver, following the circuit court's 
                                                 
1 State v. Houghton, No. 2013AP1581-CR, unpublished slip op. 
(Wis. Ct. App. May 7, 2014). 
2 The Honorable John R. Race, Judge. 
No. 
  2013AP1581-CR 
 
2 
 
denial of Houghton's motion to suppress evidence obtained during 
the course of a traffic stop. 
¶2 
This case presents questions related to the standard 
necessary for police to lawfully initiate a traffic stop.  
Specifically, 
we 
consider 
whether 
an 
officer's 
reasonable 
suspicion that a motorist is committing a traffic violation is 
always sufficient for the officer to stop the motorist, or 
whether some stops require probable cause.  We also examine 
statutes related to the placement of objects in the front 
windshield of an automobile, and weigh the effect of recent 
developments in case law related to objectively reasonable 
mistakes of law made by law enforcement officers. 
¶3 
Police Officer Jeff Price (Officer Price) pulled 
Houghton over after Officer Price observed Houghton's vehicle 
traveling on a highway without a front license plate and with an 
air freshener and a GPS unit visible in the front windshield.  
Upon approaching the vehicle, Officer Price detected the odor of 
marijuana, which led him to conduct a search of Houghton's car.  
The search revealed approximately 240 grams of marijuana as well 
as various paraphernalia commonly used for packaging and 
distributing marijuana. 
¶4 
Houghton argues that the stop was not an investigatory 
stop, and thus probable cause was required.  Houghton contends 
that Officer Price lacked probable cause to stop Houghton's 
vehicle, making the subsequent search unlawful.  The State 
counters that reasonable suspicion is sufficient for police 
officers to initiate any type of traffic stop, and that Officer 
No. 
  2013AP1581-CR 
 
3 
 
Price had reasonable suspicion to pull Houghton over for a 
violation of Wis. Stat. § 346.88(3)(b) (2011-12),3 "Obstruction 
of operator's view or driving mechanism."  The State argues in 
the alternative that any mistake by Officer Price as to whether 
Houghton was operating his vehicle illegally was objectively 
reasonable, and that under the holding of the recent United 
States Supreme Court case of Heien v. North Carolina, 574 U.S. 
___, 135 S. Ct. 530 (2014), Officer Price had reasonable 
suspicion 
to 
stop 
Houghton's 
vehicle 
for 
the 
perceived 
violation. 
¶5 
We hold that an officer's reasonable suspicion that a 
motorist is violating or has violated a traffic law is 
sufficient for the officer to initiate a stop of the offending 
vehicle.  We also adopt the Supreme Court's holding in Heien 
that an officer's objectively reasonable mistake of law may form 
the basis for a finding of reasonable suspicion. 
¶6 
In this case, we hold that Wis. Stat. § 346.88 does 
not create an absolute prohibition on any object being present 
in the front windshield of a vehicle.  However, Officer Price's 
interpretation that the statute did create such a prohibition 
was objectively reasonable.  Accordingly, Officer Price had 
reasonable suspicion to stop Houghton's vehicle, and it was not 
error for the circuit court to deny Houghton's motion to 
suppress.  For these reasons, we reverse the court of appeals. 
                                                 
3 All subsequent references to the Wisconsin Statutes are to 
the 2011-12 version unless otherwise indicated. 
No. 
  2013AP1581-CR 
 
4 
 
I. FACTUAL AND PROCEDURAL BACKGROUND 
¶7 
At approximately 12:30 p.m. on April 16, 2012, Village 
of East Troy Police Officer Jeff Price was on duty in a marked 
squad car on the shoulder of Highway 20, facing east, near 
Townline Road in East Troy.  Around that time, Officer Price saw 
a blue Ford Taurus traveling westbound on Highway 20.  The car 
had no front license plate, and an air freshener suspended from 
the rearview mirror and a GPS unit were visible through the 
front windshield.  Officer Price did a U-turn, activated his 
squad car's emergency lights, and pulled the Taurus over. 
¶8 
Officer Price approached the Taurus and obtained 
identification from the occupants.  The car, which had a 
Michigan license plate attached to the back, was driven by the 
defendant, Richard E. Houghton, Jr., who is a resident of 
Michigan.  In the front passenger seat of the car was James J. 
Taracek (Taracek), Houghton's step-brother and a resident of 
East Troy.  After running a check on both Houghton and Taracek, 
Officer Price returned to the the Taurus, this time approaching 
the passenger side.  As he approached, Officer Price smelled the 
odor of marijuana coming from the car. 
¶9 
Officer 
Price 
searched 
the 
car 
and 
found 
the 
following: "two partially smoked marijuana cigarettes, a pack of 
zig-zag rolling paper, a piece of PVC tubing with a screen taped 
on one end, a large zip-lock bag containing green plant 
material, three smaller sandwich bags containing green plant 
material, a 150 count pack of sandwich bags, and an AMS digital 
scale with traces of green plant material on the weighing base."  
No. 
  2013AP1581-CR 
 
5 
 
The 
"green 
plant 
material" 
tested 
positive 
for 
Tetrahydrocannabinol (THC), the active ingredient in marijuana.  
The large "zip-lock" bag contained approximately 140 grams of 
marijuana, the three smaller sandwich bags each contained 
approximately 30 grams of marijuana, and the PVC tube contained 
approximately 9 grams of marijuana. 
¶10 In an information filed on June 5, 2012, Houghton was 
charged with one count of possession with intent to deliver THC 
(200 to 1000 grams), contrary to Wis. Stat. § 961.41(1m)(h)2.  
On July 31, Houghton filed a motion with the circuit court 
seeking suppression of the evidence obtained during the search 
of his vehicle.  Houghton argued that the lack of a front 
license plate on his car and the items in his windshield were 
not violations of Wisconsin law.  Houghton contended that 
"because no traffic violations occurred, [Officer Price] lacked 
the reasonable suspicion to justify a Terry stop."4  Therefore, 
Houghton argued, the stop violated his Fourth Amendment right 
against unreasonable search and seizure. 
¶11 The State answered Houghton's motion to suppress on 
October 16.  The State argued that Officer Price had reasonable 
suspicion to stop Houghton for three observed violations: the 
                                                 
4 Terry v. Ohio, 392 U.S. 1 (1968). 
No. 
  2013AP1581-CR 
 
6 
 
absence of a front license plate, the items in the front 
windshield, and a missing side mirror.5 
¶12 The circuit court held a motion hearing on November 2, 
at which Officer Price testified briefly about his encounter 
with Houghton.  At the end of the hearing, the circuit court 
denied the motion.  The court was equivocal about whether the 
GPS unit and air freshener were statutory violations, noting 
that "there must be a zillion cars driving around with air 
fresheners and not very many of them would get stopped by the 
traffic officer.  They've got better things to do."  However, 
the court continued, "the princip[al] reason for the stop that 
creates this reasonable and articulable suspicion is the front 
license plate missing from a vehicle, missing on Wisconsin roads 
when Wisconsin requires two plates." 
¶13 After denial of his motion to suppress, Houghton pled 
guilty to the count as charged at a hearing on February 13, 
2013.  As part of the plea agreement, the State recommended a 
two-year sentence consisting of one year of imprisonment and one 
year of extended supervision, imposed and stayed on the 
condition that Houghton complete two years of probation and pay 
a $500 fine plus costs.  After a plea colloquy, the court 
                                                 
5 Houghton's car was missing the mirror lens on the 
passenger side.  However, Officer Price did not notice the lens 
was missing from the mirror housing until after he stopped 
Houghton.  The State does not argue in this appeal that the 
missing mirror lens gave Officer Price reasonable suspicion to 
stop Houghton. 
No. 
  2013AP1581-CR 
 
7 
 
entered a judgment of conviction and accepted the sentence 
recommendation, allowing for the possibility that Houghton would 
serve probation in Michigan. 
¶14 Houghton appealed his conviction.  On appeal, Houghton 
argued that the circuit court erred by denying his motion to 
suppress evidence.  Houghton maintained his argument that 
Officer Price lacked reasonable suspicion to stop Houghton's 
vehicle.  The State conceded that Officer Price made a mistake 
of law with regard to the license plate requirement.  The State 
also conceded that under State v. Longcore, 226 Wis. 2d 1, 9, 
594 N.W.2d 412 (Ct. App. 1999), a mistake of law could not form 
the basis for a traffic stop.  The State argued, however, that 
the items in the front windshield of Houghton's car gave Officer 
Price sufficient reason to pull Houghton over. 
¶15 In an unpublished per curiam decision, the court of 
appeals reversed the judgment of conviction and remanded the 
case to the circuit court.  State v. Houghton, No. 2013AP1581-
CR, unpublished slip op. (Wis. Ct. App. May 7, 2014).  The court 
provided little explanation for its ruling, noting that: 
the only objects near Houghton's front windshield were 
a 
standard-size, 
pine-tree-shaped 
air 
freshener 
hanging from the rearview mirror and a three-by-five-
inch GPS unit attached to the lower left-hand corner.  
On these facts, we are not persuaded that there was 
probable cause to conclude that a violation of 
§ 346.88(3)(b) had occurred. 
Id. at 5. 
¶16 The court of appeals did acknowledge that the Supreme 
Court had recently granted certiorari in Heien v. North 
No. 
  2013AP1581-CR 
 
8 
 
Carolina, 749 S.E.2d 278 (N.C. 2013), which addressed whether a 
reasonable mistake of law could provide grounds for a traffic 
stop.  Houghton, No. 2013AP1581-CR, at 4 n.3.  The court noted 
that the decision in Heien could place the holding of Longcore 
in doubt, and "suppose[d] the State [could] petition the 
Wisconsin Supreme Court for review and then ask that the 
petition be held in abeyance pending the outcome in Heien."  Id. 
¶17 The State petitioned this court for review and 
requested that we hold the petition in abeyance pending 
resolution of Heien.  Following the release of the opinion in 
Heien, this court granted review on January 13, 2015. 
II. STANDARD OF REVIEW 
¶18 Whether reasonable suspicion or probable cause is 
necessary for a law enforcement officer to stop a vehicle is a 
question of law we review de novo.  See State v. Kramer, 2001 WI 
132, ¶17, 248 Wis. 2d 1009, 637 N.W.2d 35.  Whether a statute 
has been properly interpreted and applied also is a question of 
law we review de novo, but we do so "while benefitting from the 
analyses of the court of appeals and circuit court."  118th St. 
Kenosha, LLC v. DOT, 2014 WI 125, ¶19, 359 Wis. 2d 30, 41 
N.W.2d 486 (quoting 260 N. 12th St., LLC v. DOT, 2011 WI 103, 
¶39, 338 Wis. 2d 34, 808 N.W.2d 372).  Finally, whether a 
defendant's constitutional rights were violated is a question of 
constitutional fact subject to a two-step standard of review.  
State v. Phillips, 218 Wis. 2d 180, 189, 577 N.W.2d 794 (1998).  
First, we uphold the circuit court's findings of historical fact 
unless they are clearly erroneous.  State v. Williams, 2002 WI 
No. 
  2013AP1581-CR 
 
9 
 
94, ¶17, 255 Wis. 2d 1, 646 N.W.2d 834.  Then, we review the 
circuit court's determination of the constitutional question de 
novo.  Id. 
III. DISCUSSION 
¶19 We 
begin 
by 
reviewing 
the 
law 
relating 
to 
investigatory traffic stops, then examine the evolution of case 
law involving stops predicated on reasonable mistakes of law.  
We then turn to an analysis of the relevant statutes in this 
case and conclude by applying the relevant law to the facts. 
A. Probable Cause and Reasonable Suspicion 
¶20 Terry v. Ohio, 392 U.S. 1 (1968), is the seminal case 
on 
reasonable 
suspicion 
as 
justification 
for 
conducting 
investigatory stops.  In Terry, the defendant was convicted of 
carrying a concealed weapon.  Id. at 4.  The arresting officer, 
a veteran detective with almost 40 years of experience, 
confronted Terry and his associates after observing them engage 
in a pattern of suspicious behavior.  Id. at 5-7.  After 
speaking to the men briefly, the detective grabbed Terry, spun 
him around, and performed a pat down search.  Id. at 7.  The 
search revealed a .38 caliber revolver in Terry's coat pocket.  
Id.  Terry moved to suppress the evidence, arguing that the 
detective lacked probable cause to conduct the search.  Id. at 
7-8. 
¶21 The Supreme Court affirmed Terry's conviction, holding 
that "a police officer may in appropriate circumstances and in 
an appropriate manner approach a person for purposes of 
investigating possibly criminal behavior even though there is no 
No. 
  2013AP1581-CR 
 
10 
 
probable cause to make an arrest."  Id. at 22.   In order to 
justify such a seizure, police must have reasonable suspicion 
that a crime or violation has been or will be committed; that 
is, "the police officer must be able to point to specific and 
articulable facts which, taken together with rational inferences 
from those facts, reasonably warrant that intrusion."  Id. at 
21.  This "reasonable suspicion" standard was understood to be a 
lower standard than probable cause.  See id. at 35-36 (Douglas, 
J., dissenting). 
¶22 In Berkemer v. McCarty, 468 U.S. 420 (1984), the Court 
extended the reasoning underlying Terry to include traffic 
stops, holding that a police officer "who lacks probable cause 
but whose 'observations lead him reasonably to suspect' that a 
particular person has committed, is committing, or is about to 
commit" a violation may conduct a traffic stop in order to 
"'investigate the circumstances that provoke suspicion.'"  See 
id. at 439 (citation omitted).  In other words, while probable 
cause is enough to justify a traffic stop, probable cause is not 
indispensable to justify a traffic stop.  Rather, police 
officers who reasonably suspect an individual is breaking the 
law are permitted to conduct a traffic stop "to try to obtain 
information confirming or dispelling the officer's suspicions."  
Id.   
¶23  Twelve 
years 
after 
Berkemer, 
the 
Supreme 
Court 
decided Whren v. United States, 517 U.S. 806 (1996).  In Whren, 
the Court addressed whether temporarily detaining "a motorist 
who the police have probable cause to believe has committed a 
No. 
  2013AP1581-CR 
 
11 
 
civil 
traffic 
violation 
is 
inconsistent 
with 
the 
Fourth 
Amendment's prohibition against unreasonable seizures unless a 
reasonable officer would have been motivated to stop the car by 
a desire to enforce the traffic laws."  Id. at 808. 
¶24 On June 10, 1993, D.C. Metro Police officers were 
patrolling an area of the city known for drug activity.  Id.  
The officers grew suspicious of a vehicle with temporary plates 
and "youthful occupants" after seeing the driver of the vehicle 
"looking down into the lap of the passenger at his right."  Id.  
The officers stopped the vehicle after observing it driving 
erratically, and upon approaching the vehicle, they observed 
Whren in possession of crack cocaine.  Id. at 809.  Whren was 
arrested and charged with multiple drug violations.  Id.  Prior 
to trial, the defense moved to suppress the evidence on the 
theory that the officers' "ground for approaching the vehicle——
to give the driver a warning concerning the traffic violation——
was pretextual."  Id. at 809. 
¶25 In an opinion by Justice Scalia, a unanimous Court 
held that the brief detention of a motorist who police have 
probable cause to believe has violated a traffic law is not an 
unreasonable search or seizure within the meaning of the Fourth 
Amendment, even if the officer would not have initiated the stop 
without some additional law enforcement objective.  Id. at 808, 
818-19.  In other words, pretextual traffic stops——stops 
designed to investigate violations not related to the observed 
violation——are 
not 
per 
se 
unreasonable 
under 
the 
Fourth 
Amendment. 
No. 
  2013AP1581-CR 
 
12 
 
¶26 Since Whren, some have sought deeper meaning in the 
Court's assertion that, "As a general matter, the decision to 
stop an automobile is reasonable where the police have probable 
cause to believe that a traffic violation has occurred."  Id. at 
810 (emphasis added).  Some courts interpreted Whren to mean 
that probable cause——not reasonable suspicion——is required for a 
traffic stop to be reasonable.  See United States v. Delfin-
Colina, 464 F.3d 392, 396 (3d Cir. 2006) (discussing the 
uncertainty raised by Whren). 
¶27 The existence of multiple standards necessary to 
justify traffic stops in Wisconsin was implied in State v. 
Gaulrapp, 207 Wis. 2d 600, 558 N.W.2d 696 (Ct. App. 1996).  In 
Gaulrapp, the court of appeals stated that a "traffic stop is 
generally reasonable if the officers have probable cause to 
believe that a traffic violation has occurred, or have grounds 
to 
reasonably 
suspect 
a 
violation 
has 
been 
or 
will 
be 
committed."  Id. at 605 (citations omitted).  This dual-standard 
analysis continued in Longcore when the court of appeals noted 
that the officer "did not act upon a suspicion that warranted 
further investigation, but on his observation of a violation 
being committed in his presence," thus requiring the officer's 
observations to meet the probable cause standard.  Longcore, 226 
Wis. 2d at 8-9 (footnote omitted). 
¶28 Houghton urges this court to hold that this dual 
standard is correct——that an investigative stop may be based on 
reasonable suspicion, but a stop for an observed violation must 
be based on probable cause.  He argues that our decision in 
No. 
  2013AP1581-CR 
 
13 
 
State 
v. 
Popke, 
2009 
WI 
37, 
¶11, 
317 
Wis. 2d 118, 
765 
N.W.2d 569, recognized this distinction by citing Gaulrapp 
multiple times, and that stare decisis dictates that we adhere 
to it.  Houghton also argues that this dual standard provides 
proper protection to citizens' Fourth Amendment rights. 
¶29 It is undisputed that traffic stops must be reasonable 
under the circumstances.  Gaulrapp, 207 Wis. 2d at 605.  It is 
also widely accepted that traffic stops may be justified by 
either probable cause or reasonable suspicion.  Popke, 317 
Wis. 2d 118, ¶23.  The question here is whether this "either/or" 
principle means that reasonable suspicion will always suffice to 
initiate a traffic stop, or whether the nature of certain types 
of stops requires that a higher standard be met in those stops. 
¶30 We conclude that reasonable suspicion that a traffic 
law has been or is being violated is sufficient to justify all 
traffic stops.6  The prevailing case law instructs that this is 
so.  See, e.g., Delfin-Colina, 464 F.3d at 396 ("the Second, 
Sixth, Eighth, Ninth, Tenth and Eleventh Circuits have all 
construed Whren to require only that the police have reasonable 
suspicion to believe that a traffic law has been broken.") 
(internal quotation marks omitted) (citation omitted).  See also 
Berkemer, 468 U.S. at 439 ("the usual traffic stop is more 
analogous to a so-called 'Terry stop' than to a formal arrest"); 
                                                 
6 In at least some circumstances, reasonable suspicion that 
a non-traffic-related law has been broken may also justify a 
traffic stop.  Cf. State v. Harris, 206 Wis. 2d 243, 258-61, 557 
N.W.2d 245 (1996). 
No. 
  2013AP1581-CR 
 
14 
 
United States v. Ruiz, 785 F.3d 1134, 1141 (7th Cir. 2015); 
United States v. Lopez-Soto, 205 F.3d 1101, 1104-05 (9th Cir. 
2000) (collecting cases).  As the Supreme Court has noted, 
"detention of a motorist pursuant to a traffic stop is 
presumptively temporary and brief."  Berkemer, 468 U.S. at 437.  
When weighed against the public interest in safe roads, we are 
satisfied that the "temporary and brief" detention of a traffic 
stop is an "appropriate manner" in which a police officer may 
"approach a person for purposes of investigating possibly 
criminal behavior even though there is no probable cause to make 
an arrest."  Terry, 392 U.S. at 22. 
B. Reasonable Mistakes of Law 
¶31 At issue in this case is whether a seizure predicated 
by 
an 
objectively 
reasonable 
mistake 
of 
law 
violates 
constitutional protections against unreasonable searches and 
seizures. 
 
The 
Fourth 
Amendment 
to 
the 
United 
States 
Constitution and Article I, Section 11 of the Wisconsin 
Constitution provide these protections.7  The "[t]emporary 
detention of individuals during the stop of an automobile by the 
police, even if only for a brief period and for a limited 
                                                 
7 The Fourth Amendment to the United States Constitution 
provides: "The right of the people to be secure in their 
persons, houses, papers, and effects, against unreasonable 
searches and seizures, shall not be violated . . . ."  U.S. 
Const. amend. IV.  Article I, Section 11 of the Wisconsin 
Constitution uses identical language.  See Wis. Const. Art. I, 
§ 11. 
 
We 
have 
historically 
read 
these 
provisions 
as 
coextensive.  State v. Artic, 2010 WI 83, ¶28, 327 Wis. 2d 392, 
786 N.W.2d 430. 
No. 
  2013AP1581-CR 
 
15 
 
purpose, constitutes a 'seizure' of 'persons' within the 
meaning" of the Fourth Amendment.  Whren, 517 U.S. at 809-10.  
See also Popke, 317 Wis. 2d 118, ¶11. 
¶32 In the past, Wisconsin courts have held that a seizure 
predicated on a police officer's mistake of law is invalid under 
the Fourth Amendment.  See State v. Brown, 2014 WI 69, ¶22, 355 
Wis. 2d 668, 850 N.W.2d 66; Longcore, 226 Wis. 2d at 3-4.  
However, the Supreme Court's recent decision in Heien is at odds 
with these holdings. 
¶33 A brief review of the relevant case law is useful to 
provide context for our decision. 
¶34 In 1999, the court of appeals issued its opinion in 
Longcore.  Longcore involved police officer Kevin Larson, who 
became suspicious of a vehicle when he observed it leaving the 
parking lot of several closed businesses at about 2:00 a.m.  
Longcore, 226 Wis. 2d at 4.  Officer Larson also observed that 
the rear passenger window of the vehicle was missing and had 
been replaced with a plastic sheet.  Id.  Officer Larson 
believed the plastic sheet violated Wis. Stat. § 347.43(1), 
which required that safety glass be properly equipped in all 
cars manufactured after 1935.  Id.  After pulling the car over, 
Officer Larson discovered that the driver of the car, Michael 
Longcore, was operating with a suspended license.  Id. at 3. 
¶35 The circuit court concluded that the stop was valid, 
reasoning, "[T]he officer believed a traffic regulation was 
being violated, the regulation is ambiguous, the officer's 
interpretation was reasonable and therefore his suspicion that 
No. 
  2013AP1581-CR 
 
16 
 
the law was violated was reasonable."  Id. at 5.  However, the 
court of appeals reversed the circuit court.  The court of 
appeals stated: 
If the facts would support a violation only under a 
legal misinterpretation, no violation has occurred, 
and thus by definition there can be no probable cause 
that a violation has occurred.  We conclude that when 
an officer relates the facts to a specific offense, it 
must indeed be an offense; a lawful stop cannot be 
predicated upon a mistake of law. 
Id. at 9. 
¶36 Longcore was affirmed by this court in a per curiam 
opinion after the court divided 3-3 on whether to affirm or 
reverse the court of appeals.  State v. Longcore, 2000 WI 23, 
233 Wis. 2d 278, 607 N.W.2d 620. 
¶37 This court was confronted with a similar scenario 14 
years later in Brown.  On the night of July 3, 2010, Antonio 
Brown and a friend attended a barbeque together.  Brown, 355 
Wis. 2d 668, ¶8.  After the barbeque, the friend drove Brown 
home in Brown's car because Brown was too intoxicated to drive 
himself.  Id.  The two were stopped by Milwaukee police officers 
William Feely and Michael Wawrzonek, who believed that an unlit 
bulb in the car's tail lamp violated Wis. Stat. § 347.13(1).  
Id., ¶¶2, 7.  The officers eventually conducted a search of the 
vehicle, which revealed a firearm under the front seat.  Id., 
¶7. 
¶38 Brown sought to suppress the evidence, arguing that 
the stop of his car was unconstitutional and the subsequent 
search was therefore invalid.  See id., ¶12.  The court of 
No. 
  2013AP1581-CR 
 
17 
 
appeals held that the police lacked probable cause or reasonable 
suspicion to stop Brown's vehicle, and because there was no 
probable cause or reasonable suspicion to support the stop, the 
evidence from the search should have been suppressed.  Id., 
¶¶14-16. 
¶39 This court affirmed the court of appeals.  The 
majority opinion noted that prior holdings provided "if the 
officers' interpretation of the law were incorrect . . . the 
stop would be unconstitutional because a lawful stop cannot be 
predicated upon a mistake of law."  Id., ¶22 (citing Longcore, 
226 Wis. 2d at 9).  In examining the relevant statutes, the 
court determined that Wis. Stat. § 347.13(1) did not require 
every single light bulb in a vehicle's tail lights to work.  
Id., ¶3.  Rather, the statute required only that the tail lights 
"be in proper working condition" and visible from 500 feet away 
in the dark.  Id.  Thus, "[b]ecause having one unlit bulb on the 
back of a vehicle does not on its own violate the statutory 
requirements for tail lamps, the State . . . failed to show that 
the officers had probable cause to believe that a traffic 
violation had occurred."  Id., ¶38. 
¶40 In dissent, Justice Roggensack——joined by Justice 
Ziegler——argued that a search based on a reasonable mistake of 
law is constitutional.  Id., ¶91 (Roggensack, J., dissenting).  
Specifically, an officer's mistake of law is reasonable if a 
statute is "ambiguous or unclear so that an objectively 
reasonable officer could form a reasonable belief that a 
violation was occurring, even when it was not."  Id. 
No. 
  2013AP1581-CR 
 
18 
 
¶41 Shortly after Brown, the Supreme Court also considered 
the issue of a seizure premised on a police officer's mistake of 
law.  On the morning of April 29, 2009, a police sergeant began 
to follow a vehicle after noticing that the driver looked "very 
stiff and nervous."  Heien, 135 S. Ct. at 534.  When the vehicle 
braked, the sergeant noticed that one of the vehicle's brake 
lights was not working and he stopped the vehicle.  Id.  While 
issuing a written warning for the broken brake light, the 
sergeant became suspicious of the behavior of the occupants and 
their conflicting answers to questions he asked.  Id.   The 
sergeant asked for and received consent to search the vehicle, 
whereupon he discovered a bag containing cocaine.  Id.  Heien 
was arrested and charged with attempted trafficking in cocaine.  
Id. at 535-36. 
¶42 As it turned out, having only one functioning brake 
light is not a violation of law in North Carolina.  Id. at 536.  
Thus, on appeal, the Supreme Court had to determine whether the 
sergeant's mistake of law nevertheless could have provided "the 
reasonable suspicion necessary to uphold the seizure under the 
Fourth Amendment."  Id. at 534. 
¶43 The Court began its decision by noting that under the 
Fourth Amendment: 
a search or seizure may be permissible even though the 
justification for the action includes a reasonable 
factual mistake.  An officer might, for example, stop 
a motorist for traveling alone in a high-occupancy 
vehicle lane, only to discover upon approaching the 
car that two children are slumped over asleep in the 
No. 
  2013AP1581-CR 
 
19 
 
back seat.  The driver has not violated the law, but 
neither has the officer violated the Fourth Amendment. 
Id. 
¶44 The Court held that an objectively reasonable mistake 
of law could give rise to reasonable suspicion.  "Because the 
officer's mistake about the brake-light law was reasonable, the 
stop . . . was lawful under the Fourth Amendment."  Id.  In 
support of this holding, the Court noted, "To be reasonable is 
not to be perfect, and so the Fourth Amendment allows for some 
mistakes on the part of government officials, giving them fair 
leeway for enforcing the law in the community's protection."  
Id. at 536. 
¶45 The Court further explained: 
Reasonable suspicion arises from the combination of an 
officer's 
understanding 
of 
the 
facts 
and 
his 
understanding of the relevant law.  The officer may be 
reasonably mistaken on either ground.  Whether the 
facts turn out to be not what was thought, or the law 
turns out to be not what was thought, the result is 
the same: the facts are outside the scope of the law.  
There is no reason, under the text of the Fourth 
Amendment or our precedents, why this same result 
should be acceptable when reached by way of a 
reasonable mistake of fact, but not when reached by 
way of a similarly reasonable mistake of law. 
Id. 
¶46 Thus, under Heien, a seizure predicated on reasonable 
suspicion based on a law enforcement officer's objectively 
reasonable mistake of law is not a violation of an individual's 
Fourth Amendment rights.  This holding, however, stands in stark 
contrast to the precedents established in Longcore and Brown.  
We therefore must determine which rule controls. 
No. 
  2013AP1581-CR 
 
20 
 
¶47 The majority opinion in Brown noted that the parties 
in that case agreed that a traffic stop predicated on a mistake 
of law was unconstitutional.  Brown, 355 Wis. 2d 668, ¶22.  This 
agreement between the parties was based on their common 
understanding that Longcore was the settled and accepted law of 
Wisconsin.  Id.  As noted above, the court of appeals in 
Longcore "conclude[d] that when an officer relates the facts to 
a specific offense, it must indeed be an offense; a lawful stop 
cannot be predicated upon a mistake of law."  Longcore, 226 
Wis. 2d at 9.  However, the court of appeals provided no 
authority for this proposition. 
¶48 The majority opinion in Brown also cited to a number 
of federal circuit courts that have held that a mistake of law 
cannot provide the basis for a traffic stop.  Brown, 355 
Wis. 2d 668, ¶23.  While those cases undoubtedly provided 
persuasive authority at the time Brown was decided, the Supreme 
Court's decision in Heien abrogated those cases which were based 
on the Fourth Amendment, as the Supreme Court has the final say 
on the meaning of the Fourth Amendment. 
¶49 Of 
course, 
it 
is 
uncontested 
that 
a 
state's 
constitution may provide citizens with protections beyond those 
afforded by the United States Constitution.  However, we have 
traditionally understood the Wisconsin Constitution's provision 
on search and seizure to be coextensive with the Fourth 
Amendment.  State v. Artic, 2010 WI 83, ¶28, 327 Wis. 2d 392, 
786 N.W.2d 430. 
No. 
  2013AP1581-CR 
 
21 
 
¶50 "Where . . . the language of the provision in the 
state constitution is 'virtually identical' to that of the 
federal 
provision . . . , 
Wisconsin 
courts 
have 
normally 
construed the state constitution consistent with the United 
States 
Supreme 
Court's 
construction 
of 
the 
federal 
constitution."  State v. Agnello, 226 Wis. 2d 164, 180-81, 593 
N.W.2d 427 (1999) (citing State v. Tompkins, 144 Wis. 2d 116, 
133, 423 N.W.2d 823 (1988)).  Here, the relevant portions of the 
federal and state constitutions are "virtually identical."  
Compare U.S. Const. amend. IV with Wis. Const. art. I, § 11.  
Accordingly, our standard practice dictates that we interpret 
the search and seizure provision of the Wisconsin Constitution 
consistently with the search and seizure provision of the United 
States Constitution. 
¶51 We are sensitive to the fact that Brown was decided 
only one year ago.  It is unusual for this court to overrule a 
holding after such a short period of time.  However, it would be 
equally unusual for this court to ignore a holding of the 
Supreme Court that interprets a provision of the United States 
Constitution virtually identical to a provision in the Wisconsin 
Constitution. 
¶52 Accordingly, we hold that an objectively reasonable 
mistake of law by a police officer can form the basis for 
reasonable suspicion to conduct a traffic stop.  All Wisconsin 
cases holding otherwise are hereby overruled to the extent they 
conflict with this holding. 
C. Pertinent Statutes 
No. 
  2013AP1581-CR 
 
22 
 
¶53 Before analyzing the case at hand, we consider the 
statutes that formed the basis for Officer Price's stop of 
Houghton.  For Officer Price's interpretation of these statutes 
to be "objectively reasonable," we must first consider their 
meaning. 
¶54 Our purpose in interpreting a statute is to "determine 
what the statute means so that it may be given its full, proper, 
and intended effect."  State ex rel. Kalal v. Circuit Ct. for 
Dane Cnty., 2004 WI 58, ¶44, 271 Wis. 2d 633, 681 N.W.2d 110.  
To do this, we begin with the language of the statute, giving 
words their "common, ordinary, and accepted meaning"; technical 
words are given their technical or special definitional meaning.  
Id., ¶45.  We then consider that language in light of the 
statute's structure and context as well as in "relation to the 
language of surrounding or closely-related statutes . . . to 
avoid absurd or unreasonable results."  Id., ¶46.  See Force ex 
rel. Welcenbach v. Am. Family Mut. Ins. Co., 2014 WI 82, ¶30, 
356 Wis. 2d 582, 850 N.W.2d 866.  A statute's "context" includes 
its statutory history, which "encompasses previously enacted and 
repealed provisions of [the] statute."  Richards v. Badger Mut. 
Ins. Co., 2008 WI 52, ¶22, 309 Wis. 2d 541, 749 N.W.2d 581. 
¶55 "If this process of analysis yields a plain, clear 
statutory meaning . . . the statute is applied according to this 
ascertainment of its meaning."  Kalal, 271 Wis. 2d 633, ¶46 
(quoting Bruno v. Milwaukee Cnty., 2003 WI 28, ¶20, 260 
Wis. 2d 633, 660 N.W.2d 656).  However, if the meaning of the 
statute is unclear after examining the statute's language, we 
No. 
  2013AP1581-CR 
 
23 
 
will consult extrinsic sources, including items of legislative 
history, to resolve any ambiguities.  Id., ¶50. 
¶56 The Wisconsin Statutes contain a tremendous number of 
provisions directed toward safety on the roadway.  At the fore 
in this case are statutory sections related to Wisconsin's 
unobstructed windshield requirement, set forth in Wis. Stat. 
§ 346.88, that motorists have a clear view of the roadway when 
operating a vehicle.  At issue in this case are subsections 
346.88(3)(a) and (3)(b).  These sections provide: 
(3)(a) No person shall drive any motor vehicle 
with any sign, poster or other nontransparent material 
upon the front windshield, front side wings, side 
windows in the driver's compartment or rear window of 
such vehicle other than a certificate or other sticker 
issued by order of a governmental agency.  Such 
permitted sticker shall not cover more than 15 square 
inches of glass surface and shall be placed in the 
lower left-hand corner of the windshield; the left 
corner being on the driver's left when seated behind 
the wheel. 
(b) No person shall drive any motor vehicle upon 
a highway with any object so placed or suspended in or 
upon the vehicle so as to obstruct the driver's clear 
view through the front windshield. 
¶57 The first thing we note about these provisions is that 
each provision has a slightly different character.  Subsection 
(3)(a) appears to be an absolute prohibition on the placement of 
"any sign, poster or other nontransparent material upon the 
front windshield, front side wings, side windows in the driver's 
compartment or rear window of" a vehicle, with a small exception 
for government certificates or stickers.  Subsection (3)(b), on 
the other hand, forbids the placement of all items if they would 
No. 
  2013AP1581-CR 
 
24 
 
"obstruct the driver's clear view through the front windshield."  
In other words, subsection (3)(a) appears to be a strict 
prohibition on a narrow group of items, while subsection (3)(b) 
is a slightly more forgiving prohibition that applies to all 
items. 
¶58 The State urges this court to adopt a reading of these 
subsections that a driver may have nothing attached to or 
suspended from the front windshield——including the rearview 
mirror——except those items specifically exempted in subsection 
(3)(a).  The State made clear at oral argument that this 
prohibition would apply to oil change stickers and rosaries as 
well as standard pine-tree-shaped air fresheners.8 
¶59 We note that the interpretation of these subsections 
is a close case.  In truth, however, we are unpersuaded that the 
purpose of subsections (3)(a) and (3)(b) is to create an 
absolute prohibition on any items being attached to or suspended 
from a vehicle's front windshield or rearview mirror. 
¶60 Subsection (3)(a) creates an absolute prohibition on 
"any sign, poster or other nontransparent material upon the 
                                                 
8 "Little Trees" air fresheners have been sold in the United 
States since the mid-1950s.  The air fresheners were created by 
German-Jewish chemist Julius Samaan, who fled the Nazis for 
North America before developing his product.  The Car-Freshener 
Corporation of Watertown, New York, now offers Little Trees air 
fresheners in some 60 scents.  Car-Freshener Corporation's 
president claims the company has sold "billions" of air 
fresheners in its history.  See generally Hilary Greenbaum and 
Dana Rubenstein, Who Made That? (Little Trees), New York Times 
Magazine, 19 (Mar. 4, 2012). 
No. 
  2013AP1581-CR 
 
25 
 
front windshield . . . ."  By contrast, another provision of the 
same statute, subsection (4), states: "The windshield, side 
wings and side and rear windows of a motor vehicle shall be kept 
reasonably clean at all times."  (Emphasis added.)  We see no 
reason why the legislature would choose to ban oil change 
stickers, often no more than one or two square inches in size 
and placed in a top corner of a windshield, but require that 
same area of a windshield be only "reasonably" clean.9  Instead, 
we interpret subsection (3)(a) to prohibit the attachment of 
"sign[s], poster[s]," and other items of a similar nature to the 
                                                 
9 At the motion hearing, the circuit court briefly examined 
Officer Price about the area of the windshield that is within 
reach of the wipers.  The court noted that "manufacturers 
determine the area, that is the area that's critical for the 
operation 
of 
a 
motor 
vehicle 
as 
determined 
by 
the 
manufacturers."  The court asked Officer Price whether it would 
be reasonable to define an obstruction as something that 
obstructs the area within the extent of wiper coverage. 
Officer Price did not specifically answer the question, but 
the question itself raises its own interesting questions.  For 
example, what if the area of the windshield beyond the range of 
the wipers is entirely covered with snow?  Under the State's 
argument, the presence of the snow may not be a violation.  
However, if the driver were to stop and clean the entire 
windshield——thereby exposing a one-inch by two-inch oil change 
sticker——the driver may then be subject to a ticket, even though 
the driver's view would be significantly less obstructed than it 
would have been had the driver not cleaned away the snow. 
No. 
  2013AP1581-CR 
 
26 
 
front windshield of a motor vehicle.10  See State v. Engler, 80 
Wis. 2d 402, 408-09, 259 N.W.2d 97 (1977) ("The doctrine of 
ejusdem generis . . . provides that when a general word is used 
in a statute, either preceded or followed by specific words in 
an enumeration, the general word is construed to embrace 
something similar to the specific word."). 
¶61 Unlike subsection (3)(a), subsection (3)(b) applies to 
"any object" in or on a vehicle.  However, an object is 
prohibited only if it "obstruct[s] the driver's clear view 
through the front windshield."  The key term in this provision——
"obstruct"——is not defined by the statutory scheme.  As such, we 
give the term its "common, ordinary, and accepted meaning."  
Kalal, 271 Wis. 2d 633, ¶45. 
¶62 Black's Law Dictionary defines "obstruct" as "To block 
or 
stop 
up . . . to 
close 
up 
or 
close 
off, 
esp. 
by 
obstacle . . . .  To make difficult or impossible; to keep from 
happening; hinder . . . .  To cut off a line of vision; to shut 
out . . . ."  Black's Law Dictionary 1246 (10th ed. 2014) 
                                                 
10 At oral argument, the State was asked about the legality 
of a plastic I-Pass prepaid toll collection transponder attached 
to a front windshield.  The State postulated that an I-Pass 
transponder would be exempt from Wis. Stat. § 346.88(3)(a) for 
two reasons: because it can be affixed behind the rearview 
mirror, and because it is issued by a government agency.  
However, 
subsection 
(3)(a) 
exempts 
only 
certificates 
and 
stickers issued by a government agency, and makes no exemption 
for any otherwise-prohibited item that is placed behind the 
rearview mirror.  Thus, we fail to see how the State's strict 
reading of the statute would not also outlaw the use of an I-
Pass transponder. 
No. 
  2013AP1581-CR 
 
27 
 
(emphasis added).  This definition suggests that an object needs 
to have more than a de minimus effect on the driver's vision to 
be considered an "obstruction" of a driver's clear view. 
¶63 Although there appears to be no published case law 
directly on point, Walker v. Baker, 13 Wis. 2d 637, 109 
N.W.2d 499 (1961), indirectly supports this position.  Walker 
was a tort case in which the defendant, Baker, was found liable 
for Walker's injuries incurred in an automobile accident.  At 
trial, the circuit court denied Baker's request to include a 
jury instruction for plaintiff's negligence related to Walker's 
possibly "obstructed view through his windshield."  Id. at 643-
44.  This court noted: 
While there is testimony that Walker had a pair 
of plastic dice suspended over his windshield, there 
is no evidence that this interfered with his vision, 
and it would be pure speculation on the part of the 
jury so to find.  The trial court properly refused to 
submit the requested instruction as to this aspect of 
the case. 
Id. at 644. 
¶64 It seems likely that, had Walker's "plastic dice 
suspended over his windshield" been a violation of Wis. Stat. 
§ 346.88,11 a jury instruction would have been in order. 
¶65  Given 
the 
above, 
we 
conclude 
that 
Wis. 
Stat. 
§ 346.88(3)(b)——which requires that an object "obstruct" a 
                                                 
11 Wisconsin Stat. § 346.88 has not changed since there was 
a comprehensive revision of the motor vehicle code in 1957.  See 
Chapter 260, Laws of 1957.  In fact, much of the language in 
§ 346.88 is unchanged since 1929.  See §§ 85.35(1) and (3), 1929 
Statutes. 
No. 
  2013AP1581-CR 
 
28 
 
driver's clear view to be a violation——does not mean that every 
object in a driver's clear view is a violation.  Rather, we 
interpret subsection (3)(b) as requiring a material obstruction—
—even if minor——in order to be considered a violation of the 
statute. 
D. Analysis 
¶66 Having concluded both that reasonable suspicion can 
form the basis for any traffic stop and that an officer can form 
reasonable suspicion to initiate a traffic stop based on an 
objectively reasonable mistake of law, and having addressed the 
statutory sections at issue in this case, we turn to the 
ultimate question of whether Officer Price's initiation of a 
traffic stop against Houghton violated Houghton's constitutional 
rights. 
¶67 The State contends that Officer Price's stop of 
Houghton was not based on a mistake of law because the presence 
of the GPS unit and air freshener in Houghton's front windshield 
was indeed a violation of Wis. Stat. § 346.88.  The State argues 
in the alternative that any mistake of law by Officer Price as 
to whether those items violated the statute was objectively 
reasonable.  Houghton counters that it was not objectively 
reasonable for Officer Price to interpret the statute as 
carrying an absolute prohibition on all items in the front 
windshield, pointing to Justice Kagan's concurrence in Heien—— 
joined 
by 
 
Justice 
Ginsburg——in 
which 
she 
stated 
that 
objectively reasonable mistakes of law are "exceedingly rare."  
Heien, 135 S. Ct. at 541 (Kagan, J., concurring). 
No. 
  2013AP1581-CR 
 
29 
 
¶68 Justice Kagan's concurrence also expanded on what 
could constitute an objectively reasonable mistake of law: 
A court tasked with deciding whether an officer's 
mistake of law can support a seizure thus faces a 
straightforward question of statutory construction.  
If the statute is genuinely ambiguous, such that 
overturning 
the 
officer's 
judgment 
requires 
hard 
interpretive work, then the officer has made a 
reasonable mistake.  But if not, not.  As the 
Solicitor General made the point at oral argument, the 
statute must pose a "really difficult" or "very hard 
question of statutory interpretation." 
Id. 
¶69 Justice Kagan noted that the difference between a 
"stop lamp" and a "rear lamp" in the North Carolina statute 
offered "conflicting signals" as to how the statute should be 
interpreted.  Id. at 541-42.  She concluded that the sergeant's 
interpretation of the statute was objectively reasonable because 
the sergeant's "judgment, although overturned, had much to 
recommend it."  Id. at 542. 
¶70 Here, we conclude that Officer Price's interpretation 
of 
Wis. 
Stat. 
§ 346.88——that 
the 
statute 
prohibited 
the 
placement of any object in the front windshield——was objectively 
reasonable.  That the statute has never been interpreted before 
No. 
  2013AP1581-CR 
 
30 
 
weighs in favor of this decision.12  See id. at 540 (majority 
opinion) ("This 'stop lamp' provision, moreover, had never been 
previously construed by North Carolina's appellate courts.").  
Our conclusion that the analysis of the statute is a close call 
also advances this conclusion.  See id. at 542 (Kagan, J., 
concurring) ("The critical point is that the statute poses a 
quite difficult question of interpretation . . . ."). 
¶71 Because "a reasonable judge could agree with the 
officer's view" in this case, id. at 541, we hold that Officer 
Price's mistake of law was objectively reasonable, and that the 
stop of Houghton's vehicle therefore was not unlawful. 
¶72 We turn briefly to the issue of Houghton's "missing" 
front license plate.  Although the State concedes that Officer 
Price's interpretation of the license plate statute was not 
objectively reasonable, we choose to address this issue to 
                                                 
12 We note that some unpublished Wisconsin cases have found 
reasonable suspicion or probable cause of a violation of 
subsection (3)(b) based on items hanging from a rearview mirror.  
E.g., State v. Currie, No. 2011AP322-CR, unpublished slip op., 
¶2 (Wis. Ct. App. Jul. 19, 2011) ("a very large air freshener"); 
State v. Jury, No. 2010AP622-CR, unpublished slip op., ¶7 (Wis. 
Ct. App. Sept. 1, 2010) (necklace visible "from a distance of 
200 feet"); State v. Avery, No. 2001AP1995-CR, ¶4 (Wis. Ct. App. 
Feb. 13, 2002) ("a bunch of stuff hanging from the rearview 
mirror").  We cite these cases not for any persuasive authority, 
but merely to show that the issue of windshield obstruction does 
arise in Wisconsin from time to time. 
In any event, none of these cases suggest either way 
whether subsection (3)(b) is an absolute prohibition on all 
items placed in a front windshield. 
No. 
  2013AP1581-CR 
 
31 
 
provide guidance in future cases and because it was the basis of 
the circuit court's decision. 
¶73 It is clear that Wis. Stat. § 341.15 requires a 
vehicle to display a front license plate only when two license 
plates are issued for that vehicle.  Officer Price's belief that 
Houghton was violating the statute by not having a front plate 
was not a reasonable mistake of law to the extent that it 
implies that all vehicles must display a front license plate. 
¶74 An officer who observes a vehicle driving without a 
front license plate may have no way of knowing whether that 
vehicle is required to display a front plate.  Whether a vehicle 
is indeed required to display a front plate is both a question 
of law and a question of fact——the operative fact being whether 
the vehicle was issued two plates.  Thus, it could perhaps be 
argued that a stop based on the lack of a front plate when the 
vehicle was issued only one plate is based on a mistake of fact 
rather than a mistake of law. 
¶75 Because searches and seizures can be based on mistakes 
of fact, see Illinois v. Rodriguez, 497 U.S. 177, 183-86 (1990); 
State v. Reierson, No. 2010AP596-CR, unpublished slip op., ¶1 
(Wis. Ct. App. Apr. 28, 2011), we confront the question of 
whether the lack of a front license plate, without more, may 
give rise to reasonable suspicion to conduct a traffic stop.  To 
answer this question in the affirmative, we would have to hold 
that it is reasonable for a police officer in Wisconsin to 
believe that, if a vehicle is operating on a Wisconsin road, it 
must have been issued two license plates. 
No. 
  2013AP1581-CR 
 
32 
 
¶76 Such 
a 
belief 
would 
usually 
be 
unreasonable.  
Wisconsin borders four other states, and residents from those 
and many other states pass through Wisconsin on a regular basis.  
That most vehicles on Wisconsin roads might be registered in 
Wisconsin and most vehicles registered in Wisconsin might be 
issued two plates is not enough to conclude that a stop of a 
vehicle solely because it lacks a front license plate passes 
constitutional muster. 
¶77 On the other hand, if an officer observes some indicia 
that a vehicle without a front license plate is from Wisconsin, 
then the officer may indeed have reasonable suspicion to stop 
the vehicle.  Perhaps the most common indication would be a 
Wisconsin plate attached to the rear of the vehicle in question.  
However, other things may clue an officer in to a vehicle's 
origins as well——for example, markings indicating an affiliation 
with a local business. 
¶78 Here, however, there was no initial indication that 
Houghton's vehicle was from Wisconsin.  Once Officer Price was 
behind Houghton's vehicle, it would have become apparent from 
the rear plate that the vehicle was registered in Michigan.   
Thus, to the extent that Officer Price may have believed that 
Houghton was violating the law by not having a front license 
plate displayed, we hold that belief was neither a reasonable 
mistake of law nor a reasonable mistake of fact. 
IV. CONCLUSION 
¶79 We hold that an officer's reasonable suspicion that a 
motorist is violating or has violated a traffic law is 
No. 
  2013AP1581-CR 
 
33 
 
sufficient for the officer to initiate a stop of the offending 
vehicle.  We also adopt the Supreme Court's holding in Heien 
that an officer's objectively reasonable mistake of law may form 
the basis for a finding of reasonable suspicion. 
¶80 In this case, we hold that Wis. Stat. § 346.88 does 
not create an absolute prohibition on any object being present 
in the front windshield of a vehicle.  However, Officer Price's 
interpretation that the statute did create such a prohibition 
was objectively reasonable.  Accordingly, Officer Price had 
reasonable suspicion to stop Houghton's vehicle, and it was not 
error for the circuit court to deny Houghton's motion to 
suppress.  For these reasons, we reverse the court of appeals. 
 
By the Court.—The decision of the court of appeals is 
reversed. 
 
 
No.  2013AP1581-CR.ssa 
 
1 
 
 
¶81 SHIRLEY 
S. 
ABRAHAMSON, 
J.   (dissenting). 
 
The 
majority opinion reverses the decision of the court of appeals 
and affirms the defendant's conviction.  The conviction was 
based on a denial of the defendant's motion to suppress evidence 
obtained from a traffic stop.  The traffic stop was predicated 
on a law enforcement officer's mistake of law, which the 
majority opinion deems "objectively reasonable."1 
¶82 By declaring for the first time that reasonable 
suspicion for a traffic stop can rest on a law enforcement 
officer's objectively reasonable mistake of law, the majority 
opinion adopts a new interpretation of Article I, Section 11 of 
the Wisconsin Constitution.  It does so solely in order to 
remain in lockstep with the United States Supreme Court's 
interpretation of the Fourth Amendment.2 
¶83 The majority opinion overturns not only the court of 
appeals decision in the instant case but also two prior 
decisions:  State v. Brown, 2014 WI 69, 355 Wis. 2d 668, 850 
N.W.2d 66, and State v. Longcore, 226 Wis. 2d 1, 594 N.W.2d 412 
(Ct. App. 1999).  What happened to precedent and stare decisis? 
¶84 I would adhere to precedent, reaffirm Brown and 
Longcore, and affirm the court of appeals decision in the 
instant case. 
                                                 
1 Majority op., ¶71. 
2 Majority op., ¶¶46-52. 
No.  2013AP1581-CR.ssa 
 
2 
 
¶85 In Brown, an opinion released just last year, this 
court held that reasonable suspicion for a traffic stop cannot 
rest on a law enforcement officer's mistake of law.3  After Brown 
was decided, the United States Supreme Court held in Heien v. 
North Carolina, 135 S. Ct. 530 (2014), that under the Fourth 
Amendment, a law enforcement officer's reasonable mistake of law 
can support reasonable suspicion for a traffic stop. 
¶86 The majority opinion in the instant case does an 
about-face, 
adopting 
the 
United 
States 
Supreme 
Court's 
interpretation of the Fourth Amendment in Heien as the correct 
interpretation of the Wisconsin Constitution. 
¶87 The drafters of the Wisconsin Constitution could have 
simply said "ditto" and incorporated the federal Bill of Rights 
into the Wisconsin Constitution.  But they did not.  Instead, 
they adopted a separate and distinct Wisconsin Declaration of 
Rights. 
¶88 In the instant case and many like it, this court is 
doing what the drafters of the Wisconsin Constitution did not 
do, 
namely 
adopting 
the 
federal 
Bill 
of 
Rights. 
 
More 
specifically, by adopting wholesale the United States Supreme 
Court's interpretation of the federal Bill of Rights as the 
proper interpretation of Wisconsin's Declaration of Rights, this 
court is in effect replacing Wisconsin's Declaration of Rights 
with its federal counterpart.  This court is not taking 
                                                 
3 State v. Brown, 2014 WI 69, ¶¶22-25, 355 Wis. 2d 668, 850 
N.W.2d 66. 
No.  2013AP1581-CR.ssa 
 
3 
 
seriously the Justices' oath of office to support the Wisconsin 
Constitution. 
¶89 Heien is binding on this court only insofar as the 
federal constitution is concerned.  It is not binding with 
regard to the state constitution.  This court need not and 
should not automatically adopt the United States Supreme Court's 
interpretation 
of 
the 
Fourth 
Amendment 
as 
the 
proper 
interpretation of Article I, Section 11 of the Wisconsin 
Constitution. 
¶90 In Brown, this court set forth three primary reasons 
for its determination that reasonable suspicion cannot rest on a 
law enforcement officer's mistake of law: 
1. Wisconsin precedent so stated.  In State v. Longcore, 
226 Wis. 2d 1, 9, 594 N.W.2d 412 (Ct. App. 1999), the 
court of appeals declared that "a lawful [traffic] 
stop cannot be predicated upon a mistake of law." 
2. Other jurisdictions were in accord.  A substantial 
majority of both the federal circuit courts and the 
state courts that had addressed the issue had 
concluded that a law enforcement officer's mistake of 
law cannot support reasonable suspicion or probable 
cause for a traffic stop.4 
3. Holding that a law enforcement officer's mistake of 
law could support lawful traffic stops would defeat 
the 
purpose 
of 
the 
exclusionary 
rule. 
 
More 
                                                 
4 Brown, 355 Wis. 2d 668, ¶¶23, 25.  See also Heien v. North 
Carolina, 135 S.Ct. 530, 544 (2014) (Sotomayor, J., dissenting). 
No.  2013AP1581-CR.ssa 
 
4 
 
specifically, declining to exclude evidence that was 
gathered from a traffic stop premised on a law 
enforcement officer's erroneous view of the law 
"would remove the incentive for police to make 
certain that they properly understand the law that 
they are entrusted to enforce and obey."5 
¶91 These considerations remain persuasive and convince me 
to adhere to Brown.  A law enforcement officer's reasonable 
mistake of law cannot, in my view, render a traffic stop 
reasonable in the eyes of the Wisconsin Constitution. 
¶92 My position is supported by several cogent points that 
Justice Sotomayor makes in her dissent in Heien: 
1. An inquiry into the reasonableness of officers' 
understanding of the law breaks with longstanding 
federal and state court precedent.6 
2. The notion that the law is definite and knowable sits 
at the foundation of our legal system.  Yet, Heien 
gives 
those 
who 
enforce 
the 
law 
leeway 
in 
interpreting and understanding it.7 
                                                 
5 Brown, 355 Wis. 2d 668, ¶24 (internal quotation marks 
omitted). 
6 Heien, 135 S. Ct. at 542-43 (Sotomayor, J., dissenting). 
7 Id. at 543 (Sotomayor, J., dissenting).   
Heien purports to rest on the concept of reasonableness, 
the touchstone of the Fourth Amendment.  However, as Justice 
Sotomayor's dissent explains, 
this broad statement simply sets the standard a court 
is to apply when it conducts its inquiry into whether 
the Fourth Amendment has been violated.  It does not 
(continued) 
No.  2013AP1581-CR.ssa 
 
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3. Heien 
"further 
erod[es] 
the 
Fourth 
Amendment's 
protection of civil liberties in a context," namely 
traffic stops, "where that protection has already 
been worn down."8   
4. Heien 
is 
a 
significant 
expansion 
of 
officers' 
authority and leads one to wonder "how a citizen 
seeking to be law-abiding and to structure his or her 
behavior to avoid these invasive, frightening, and 
humiliating encounters could do so."9 
5. Because traffic stops can be annoying, frightening 
and 
humiliating, 
they 
have 
consequences 
for 
                                                                                                                                                             
define the categories of inputs that courts are to 
consider when assessing the reasonableness of a search 
or seizure, each of which must be independently 
justified. What this case requires us to decide is 
whether a police officer's understanding of the law is 
an input into the reasonableness inquiry, or whether 
this inquiry instead takes the law as a given and 
assesses an officer's understanding of the facts 
against a fixed legal yardstick. 
Id. at 542. 
8 Heien, 135 S. Ct. at 543 (Sotomayor, J., dissenting).   
For discussion of the "wearing down" of the protections of 
the Fourth Amendment in Wisconsin courts, see Alan Ball, How 
Effective 
are 
Fourth-Amendment 
Arguments 
in 
the 
Wisconsin 
Supreme 
Court?, 
SCOWstats, 
June 
22, 
2015,  
http://www.scowstats.com/2015/06/22/how-effective-are-fourth-
amendment-arguments-in-the-wisconsin-supreme-court/ 
(last 
visited June 30, 2015) (reviewing decisions of the Wisconsin 
Supreme Court and concluding that the current judicial climate 
is inhospitable to Fourth Amendment arguments). 
9 Heien, 135 S. Ct. at 544 (Sotomayor, J., dissenting). 
No.  2013AP1581-CR.ssa 
 
6 
 
individuals 
and 
communities 
"and 
for 
their 
relationships with the police . . . ."10 
6. Law 
enforcement 
officers 
have 
not 
been 
unduly 
hampered in the exercise of their duties by the rule 
that their mistakes of law are not considered as part 
of the Fourth Amendment reasonableness inquiry.11 
7. There is scarcely any law that does not admit of some 
ingenious doubt.12  A decision interpreting a law will 
not immunize the law from further interpretation.  
Interpretation of the law constitutes a substantial 
portion of court business. 
¶93 These considerations apply with equal force in the 
context of the Wisconsin Constitution.  Both precedent and 
policy compel me to conclude that a traffic stop premised on a 
law enforcement officer's mistake of law is unreasonable and 
thus unlawful under Article I, Section 11 of the Wisconsin 
Constitution. 
¶94 Accordingly, the traffic stop at issue in the instant 
case, which was premised on a law enforcement officer's mistake 
                                                 
10 Heien, 135 S. Ct. at 544 (Sotomayor, J., dissenting). 
11 Id. 
12 Id.  Justice Kagan authored a concurrence in Heien 
explaining that an officer has made a reasonable mistake of law 
only when the statute in question is "genuinely ambiguous," 
"requires hard interpretive work," and "poses a quite difficult 
question."  Heien, 135 S. Ct. at 541-42 (Kagan, J., concurring).  
I do not think the mistake of law at issue in the instant case 
falls within this exacting interpretation of what constitutes a 
reasonable mistake of law. 
No.  2013AP1581-CR.ssa 
 
7 
 
of law, was unlawful.  The defendant's motion to suppress the 
evidence obtained from the unlawful traffic stop should have 
been granted, and the defendant's conviction should be reversed. 
¶95 For the reasons set forth, I dissent. 
¶96 I am authorized to state that Justice ANN WALSH 
BRADLEY joins this opinion. 
No.  2013AP1581-CR.ssa 
 
 
 
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