The Volokh Conspiracy

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Idaho Supreme Court Rules Fourth Amendment Violated When Drug-Sniffing Dog "Intermeddled" With Defendant's Car

Nero the police dog put his paws on the side of the car, which qualifies as a trespass, and thereby also a "search" under the Fourth Amendment.


Police dog | Arisha Singh /
(Arisha Singh /

In State v. Dorff, a decision issued on March 20, the Idaho Supreme Court suppressed evidence obtained in a police search of a car because Nero the drug-sniffing police dog committed "trespass" by "intermeddling" with the defendant's vehicle. More specifically, Nero put his paws on the side of the car:

For the reasons discussed below, a "search" occurs when a drug dog trespasses against the exterior of a vehicle during a "free air" sniff if its physical contact with the vehicle amounts to "intermeddling" at common law. In this case, a drug dog intermeddled with Dorff's vehicle when it jumped onto the driver side door and window, planted two of its paws, and sniffed the vehicle's upper seams. Accordingly, law enforcement conducted a warrantless and unlawful "search" of Dorff's vehicle by way of its drug dog.

Nero should have studied the relevant legal precedents more carefully! His  more learned predecessor, Caligula, would never have made such an obvious mistake.

On a slightly more serious note, I am no Fourth Amendment expert. But the case does interest me in my capacity as both a property law professor, and a longtime dog owner.

The majority opinion, written by Justice Brody, reasons that a "search" occurs if a police officer (or, in this case, his dog) trespasses on the defendant's property, and that physical contact with the property qualifies as a trespass if it rises to the level of "intermeddling":

At common law, a "trespass" to chattel occurs when an actor violates "the dignitary interest in the inviolability of chattels," PROSSER & KEETON, at 87, i.e., those "interests" that comprise the "bundle of sticks" (e.g., the right to use, possess, and exclude).An actor violates such interest"either by intentionally using or otherwise intermeddling with a chattel in the possession of another or by continuing to use or intermeddle therewith after a privilege to do so has been terminated." RESTATEMENT (FIRST) OF TORTS § 217 (1934) (emphasis added)….

The physical contact with the chattel must amount to "intermeddling" for a "trespass" to occur, and although some contact to the exterior surface of a chattel in every-day type commotions will be insufficient, entering into another's chattel—and thereby intruding against the inviolability of the chattel's "close"—is a form of "intermeddling" that suffers no de minimus exception.... Intermeddling is the difference between someone who brushes up against your purse while walking by—and someone who, without privilege or consent, rests their hand on your purse or puts their fingers into your purse…. It is also the difference between a dog's tail that brushes against the bumper of your vehicle as it walks by—and a dog who, without privilege or consent, approaches your vehicle to jump on its roof, sit on its hood, stand on its window or door—or enter into your vehicle….

Nero fell on the "intermeddling" side of the line:

[W]hen Nero approached the driver's side on his second pass, he clearly trespassed against Dorff's vehicle. The footage reflects that when Nero reached the front driver side door, he jumped up onto the door, and planted his two front paws on the door (and then the window) as he sniffed the upper seams of the vehicle. Although the length of time Nero had his paws on the vehicle is not dispositive of whether Nero's doing so amounted to intermeddling, the seconds that do pass while Nero stood on, and occupied, Dorff's vehicle—without privilege or Dorff's consent—is enough to objectively constitute a wrongful trespass against, and intermeddling with, Dorff's vehicle, and his right to exclude. And as we have said before, "there is no asterisk to the Fourth Amendment excusing the unconstitutional acts of law enforcement when they are accomplished by means of a trained dog."Howard, 169 Idaho at 382, 496 P.3d at 868. Thus, although it was accomplished by Nero, it was law enforcement who violated Dorff's dignitary interest in maintaining the inviolability of his chattel….


I think it's pretty obvious that a drug-sniffing dog jumping on the side of your car and placing his paws on the window qualifies as a "trespass to chattel" under the common law. And that's true regardless of whether it can be described as "intermeddling." Such an action is also a trespass because it temporarily "dispossesses" the owner, in so far as he cannot safely drive the car so long as the dog is on it.

In a dissenting opinion, Justice Moeller appears to agree that Nero's actions may qualify as a search, but argues that it wasn't an "unreasonable" one because it wasn't a sufficiently grave "physical intrusion." It therefore didn't violate the Fourth Amendment. I will leave that issue to the Fourth Amendment experts.

Chief Justice Bevan joined Moeller's dissent, and also wrote a separate dissent arguing that "a dog's instinct to jump cannot be imputed to its officer-handler when the dog acts without instruction" and therefore Nero's actions do not qualify as a true search by the police. This argument makes little sense. The dog didn't just spontaneously jump on the car. It did so while sniffing for drugs under the direction of his handler. Surely the officer is responsible for controlling the dog in such a situation.

If I am walking my dog down the street and she jumps on another pedestrian—or on a car—surely I am responsible, and am liable for any damage or trespass the dog inflicts. Police K-9 handlers should be held to at least the same standards as ordinary dog owners.

The possibility of trespass to chattel is far from the only problem with drug-sniffing dogs. They also often make mistakes, including ones motivated by the desire to please their law-enforcement handlers, who may want false alerts in order to facilitate asset forfeiture abuse. In an era of widespread marijuana legalization, drug-sniffing dogs have become even less reliable than before, because they may "alert" to marijuana, despite its no longer being illegal in a given jurisdiction.