Wisconsin Supreme Court Upholds Vehicle Search Over Marijuana Odor

The Wisconsin Supreme Court has ruled that the smell of marijuana alone can give police probable cause to search a person inside a vehicle, even though legal substances may produce an identical odor. The 4-3 decision, issued by the court’s conservative majority, reverses earlier rulings from lower courts and is expected to have broad implications for law enforcement and residents across the state.

At the center of the case was a 2019 traffic stop in Marshfield involving Quaheem Moore. Police pulled Moore over for speeding and reported detecting the smell of marijuana coming from inside the vehicle. Moore, who was alone in the car at the time, told officers that a vaping device in his possession contained CBD — a legal cannabis-derived substance that smells the same as marijuana. He also explained that the vehicle was a rental belonging to his brother. Officers did not report smelling marijuana directly on Moore himself.

Despite Moore’s explanation, two officers searched him. During that search, they discovered small bags of cocaine and fentanyl in his pocket. Moore was not charged with marijuana possession, but he was charged with narcotics offenses related to the drugs found during the search.

Moore challenged the legality of the search, arguing that officers had no specific reason to believe he was personally responsible for the odor inside the car. Under constitutional standards, police must have probable cause — meaning sufficient evidence to reasonably believe a person has committed a crime — before conducting a search. Evidence obtained through an unlawful search cannot be used in court.

A circuit court judge agreed with Moore and suppressed the drug evidence, ruling that the search was not legally justified. An appeals court upheld that decision, reasoning that because cannabis-derived CBD is legal and indistinguishable in smell from illegal marijuana, officers could not be certain that a crime had occurred based solely on odor.

However, the state’s highest court disagreed.

Writing for the majority, Justice Brian Hagedorn concluded that the smell of marijuana provided sufficient probable cause under existing legal precedent. Because Moore was the only occupant of the vehicle, Hagedorn wrote, officers could reasonably infer that he was connected to the illegal substance they believed they smelled. The opinion emphasized that probable cause does not require absolute certainty — only a reasonable belief that criminal activity is likely.

The majority relied in part on a 1999 decision that held officers were justified in arresting a driver after detecting what was described as the “unmistakable” smell of marijuana. That earlier ruling treated the odor of a controlled substance as strong evidence that a crime had been committed. Although marijuana laws have evolved since then, the conservative justices maintained that the precedent still applies.

The court’s three liberal justices sharply disagreed. In a dissenting opinion, Justice Rebecca Frank Dallet argued that the earlier case law no longer reflects modern legal realities. Since cannabis-derived products have been legalized in certain forms, she wrote, officers who believe they smell marijuana may just as easily be detecting a lawful substance.

“Officers who believe they smell marijuana coming from a vehicle may just as likely be smelling raw or smoked cannabis that is not criminal activity under current law,” Dallet wrote, questioning whether odor alone remains a reliable indicator of illegal conduct. She and the other dissenting justices contended that the majority’s reasoning risks allowing searches based on assumptions that may no longer be dependable.

Moore’s attorney, Joshua Hargrove, echoed those concerns. He warned that the ruling could broaden police authority in ways that expose law-abiding citizens to intrusive searches. By allowing officers to rely on an odor that could originate from legal cannabis products, Hargrove argued, the decision may reduce accountability and make it harder for defendants to challenge questionable searches in court.

The case unfolds against the backdrop of an ongoing political debate over marijuana legalization in Wisconsin. Democratic Gov. Tony Evers has repeatedly proposed legalizing both medical and recreational marijuana, but Republicans who control the state Legislature have rejected those efforts. At the same time, GOP Assembly Speaker Robin Vos has said he is working on legislation that could legalize medical marijuana, potentially as soon as this fall.

Complicating matters further is the fact that cannabis products are already widely available in Wisconsin through a legal loophole tied to federal cannabis regulations. Because certain cannabis products that meet federal definitions can be sold legally, retailers across the state offer intoxicating cannabis items that can be purchased lawfully and produce the same smell as traditional marijuana. That gray area has created confusion for consumers and law enforcement alike, as officers may encounter products that look and smell identical to marijuana but are technically legal under current rules.

Lawmakers have indicated that this loophole may soon be addressed. Proposals under discussion could tighten regulations or close the gap entirely, with possible action coming as soon as November. If that happens, the legal landscape surrounding cannabis in Wisconsin could shift again — potentially affecting how future courts evaluate cases involving the smell of marijuana.

Wisconsin’s approach contrasts with neighboring states. Recreational marijuana has been legal for years in Michigan and Illinois, and Minnesota is set to implement legalization under legislation passed last month. As more states adopt clearer legalization frameworks, Wisconsin remains in a transitional phase, where certain cannabis products can be legally purchased even as marijuana itself remains illegal.

For now, the Wisconsin Supreme Court’s decision establishes that, within the state, the odor of marijuana remains enough to justify a search — even in a legal environment where that same smell may come from products that can be purchased lawfully.