Those of us who regularly and zealously challenge illegal searches and seizures in criminal and traffic cases were handed a victory of sorts (victory with a very small “v”) by the Wisconsin Supreme Court last month.

In State of Wisconsin v. Antonio D. Brown, 346 Wis.2d 98, the defendant was convicted in Milwaukee County of being a felon in possession of a firearm after the car he was riding in was stopped by police for having a “defective tail light.” Mr. Brown challenged the stop and subsequent search on the grounds that the officers’ interpretation of “defective” — that one out of three light “panels” (bulbs) in an otherwise illuminated tail light was not lit — was an incorrect interpretation of Wisconsin Statutes Section 347.13(1). He filed a motion to suppress the evidence seized during the search on the grounds that the stop was not “reasonable” and was, therefore, an unconstitutional intrusion.

The Circuit Court in Milwaukee County upheld the legality of the stop and denied Mr. Brown’s motion to suppress evidence. He was subsequently convicted. The Court of Appeals reversed, and the State sought review in the Supreme Court. In a disappointingly narrow 4 to 3 decision, the Supreme Court upheld the Court of Appeals decision that the officers did not have reasonable suspicion or probable cause to stop the car, and, therefore, the seizure and search were unconstitutional.

The Supreme Court’s decision in this case seems like an exercise in stating the obvious — that it is legal to drive a car with one burnt out light bulb out of three in an otherwise functioning, illuminated tail light; and that an officer cannot reasonably stop your car for having a defective tail light under those circumstances. Most reasonable people would tend to agree with that conclusion.

From that standpoint the Wisconsin Supreme Court’s ruling seems like a very minor victory for those of us fighting to maintain a strong and vital Fourth Amendment. However, the most important takeaway from this case is that a stop based upon an officer’s mistaken interpretation of the law is not reasonable — even if the officer made the mistake in “good faith” (thinking that his reading of the law was correct). The case is also illustrative of a number of aspects of well-established Fourth Amendment/search and seizure law, which are worth noting:

1. Traffic stops are considered “seizures” under our Fourth Amendment jurisprudence, and must be “reasonable” in order to pass constitutional muster.
2. If a seizure is found to be unreasonable, and, therefore, unconstitutional, then evidence obtained as a result of that seizure is generally not admissible at trial.
3. Police officers are human. They make mistakes and do not always know the law or interpret the law correctly.
4. Police officers are sometimes overzealous, and, more often than one would like to believe, will sometimes look for a reason to initiate a traffic stop (we call this a “pretext”), based upon, for example, the time of day, the proximity to a tavern, the particular neighborhood crime rate or a “gut feeling” or “hunch.”
5. Established federal and state case law is very clear that an officer may not legally initiate an encounter based upon an “unparticularized hunch” — on a hunch that is not based upon specific, reasonable grounds that show that a traffic violation (including an equipment violation) or crime is being committed or has been committed. An encounter (or traffic stop) that is based on a mere hunch is not reasonable, and is, therefore, an unconstitutional intrusion.

Mr.. Brown’s case appears to be an example of the sad but true reality that many African Americans experience every day — being stopped by police for little or no reason (often referred to as “driving while black”).

However, in addition to this “profiling” issue, many OWI (drunk driving) and possession cases begin with a questionable stop by police. If we are going to preserve the integrity and strength of our constitutional protection against unreasonable searches and seizures, then these encounters must be challenged aggressively by experienced and competent defense counsel… even when the victories seem obvious.