Without identifying specific cases, the Tennessee Supreme Court in State v. Green, expressly overruled “any prior opinions of the Court of Criminal Appeals or this Court [which] imply or provide a per se rule of probable cause based on a positive alert” by a drug dog. While the Court took great pains to explain that its opinion was not breaking new ground, Green purportedly ends the reign of the standalone odor providing probable cause for a search.
The issue has been percolating for years now, following admissions from law enforcement that nobody — canine, human, or other — can distinguish between the smell of illegal marijuana and its ubiquitous slightly less-powerful imitators, all of which now fall under the legal definition of “hemp.” Until Green, the intermediate courts, constrained by a lack of guidance from the Tennessee Supreme Court, felt duty bound to allow K-9 sniffs alone to suffice as probable cause even though the dogs could not distinguish marijuana from any of its perfectly legal substitutes.
In Green the Court finally spoke, albeit with very little clarity. First, the Court summarized prior precedent as standing for the proposition that the smell of drugs has never been allowed to justify a search, then specifically held that it overruled any of its own prior opinions to the contrary. The Court then explained that the “totality of the circumstances” meant exactly that, and, relying on federal precedent to provide a broad definition, held that “totality” could include a dog sniff even if that dog could not tell marijuana from hemp.
The totality of the circumstances in this case included three things: air fresheners hanging from a mirror, a backpack in the car that nobody wanted to claim, and the dog sniff. The Court noted in passing that the Defendant seemed suspicious and noted that the dog was trained to smell other illegal drugs. However, given that a dog trained on marijuana is scientifically no better than a coin flip for finding illegal drugs, it is difficult to see how the totality of these circumstances yielded probable cause. While smell alone is insufficient, it appears that the threshold for establishing probable cause is extremely low.
Although not substantively addressed in the opinion, the Court appeared to be open to considering whether a dog sniff now constitutes a search in light of the legalization of hemp. At least one Court of Criminal Appeals judge has already hinted at believing this to be the case. With that in mind, this will likely be the next frontier for litigation on dog sniff cases. Post Green, it will be important to (1) use preliminary hearings to lock in those cases where the dog or officer sniff is the only incriminating factor, (2) challenge the dogs themselves, and (3) continue to challenge the totality of the circumstances wherever possible.