It's official, as I expected, SCOW has adopted the dangerous precedent created by the Supreme Court of the United States ("SCOTUS") in Heien v. North Carolina, wherein the Court ruled that the police--the one group that definitely should know the law--can be excused for their ignorance of the law, so long as the ignorance was "reasonable".
The ruling in State v. Houghton, filed just yesterday, overturned SCOW's earlier cases, State v. Longcore, 2000 WI 23, 233 Wis. 2d 278, 607 N.W.2d 620 and State v. Brown, 2014 WI 69, ¶22, 355 Wis. 2d 668, 850 N.W.2d 66, which firmly held that traffic stops cannot be based upon mistakes of law. Brown was decided less than a year ago. As Justice Abrahamson decries in her dissent, "What happened to precedent and stare decisis?" (Let the decision stand.)
In Houghton, the officer pulled a car over under the mistaken belief that having no front license plate and having object (a pine tree air freshener and a small GPS unit) in the windshield of a car violates Wis. Stat. s. 346.88(3)(b). In fact, the State conceded the officer was mistaken about the legality of no front license plate, and the referenced statute only prohibits such objects that "obstruct the driver's clear view through the front windshield." The Court of Appeals ruled that these objects did not give the officer--who later found a bunch of MJ and other evidence as a result of the stop--probable cause to stop the vehicle. However, SCOW said, using Heien, that the officer's ignorance of the law was close enough and would not make the traffic stop unconstitutional.
"Why should we care?", you might ask. As Justice Jackson of SCOTUS once pointed out, the police are "engaged in the often competitive enterprise of ferreting out crime." Finding drugs and making busts scores them job and ego points. We do not want to create incentives whereby being able to convincingly feign ignorance will advance your career.
The Fourth Amendment is the only thing that prevents the police from stopping us at any time, at any place, for any reason. We are supposed to live in a free society where we get left alone unless we are doing something wrong. Allowing the police to stop cars on a mere pretext--such as a perfectly-legal air freshener dangling from the rear-view mirror--will definitely turn up more illegal drugs, but it also robs of our freedom. I'd rather we be honest about it and legalize road blocks.
SCOW had the opportunity to interpret the Wisconsin Constitution to reject the premise that the police are held to a lower standard than the citizens of Wisconsin. Instead, it chose to go along with SCOTUS and create more authority for pretextual stops. That sucks.
PRACTICE POINTER: When you bring your motion for suppression, subpoena the officer's training materials so that you can demonstrate that he/she knew what the law actually is.