Who Let the Dogs In?

Here's how it works: An officer pulls you over because you're driving a bit too fast or a bit too slow, or because you have a broken tail light, or because you're not wearing your seat belt, or because you forgot to put your new registration sticker on your license plate. He is soon joined by another officer with a drug-sniffing dog, which "alerts" when it gets near your trunk.

Or so the officers say. You have no idea what this particular dog does when it smells contraband, and the dog isn't talking. But now the police can look in your trunk. A minor traffic stop is thus transformed into an embarrassing, invasive, intimidating, time-consuming search for illegal drugs.

The Supreme Court recently gave its approval to this sort of stop-and-switch in a case involving a man named Roy Caballes, who was pulled over on Interstate 80 by an Illinois state trooper for driving six miles an hour faster than the speed limit. Caballes happened to have 282 pounds of marijuana in his trunk, but even those of us who are not pot smugglers should worry that the Court saw nothing wrong with the circumstances that led to his arrest.

Trooper Daniel Gillette testified that he became suspicious because Caballes was well-dressed and seemed nervous, the car smelled of air freshener, and the only visible belongings were two sport coats, even though Caballes said he was moving from Las Vegas to Chicago. Gillette asked for permission to search the car, which Caballes, not surprisingly, declined to grant.

Gillette got permission from a dog instead. Trooper Craig Graham, upon hearing Gillette call in the stop, decided to swing by with a drug-sniffing canine, conveniently arriving just as Gillette was writing Caballes a warning ticket. For Caballes, one sniff by that dog was the difference between a warning and a 12-year prison sentence.

But according to the Supreme Court, the sniff was not a search. "A dog sniff conducted during a concededly lawful traffic stop that reveals no information other than the location of a substance that no individual has any right to possess does not violate the Fourth Amendment," wrote Justice John Paul Stevens for the six-member majority.

The decision built on a 1983 ruling that said "subjecting luggage to a 'sniff test' by a well-trained narcotics detection dog does not constitute a 'search' within the meaning of the Fourth Amendment" because it "discloses only the presence or absence of narcotics, a contraband item." In other words, the only privacy interest it violates is a drug smuggler's desire to conceal his stash, which is not protected by the Fourth Amendment's prohibition of "unreasonable searches and seizures."

This argument is based on a myth. As Justice David Souter, one of two dissenters in Illinois v. Caballes, pointed out, "the infallible dog ... is a creature of legal fiction."

Souter cited examples from court cases of dogs with error rates of up to 38 percent. "Dogs in artificial testing situations return false positives anywhere from 12.5 to 60 percent of the time," he added.

In short, it is simply not true that a drug-sniffing dog "discloses only the presence or absence of narcotics." Even leaving aside the possibility of deliberate deception or honest error by police officers eager to turn a hunch into probable cause, the dogs themselves make mistakes, responding to subconscious cues from their handlers, alerting to food or residual odors of drugs that are no longer present, mistaking items associated with drugs for the drugs themselves, and so on.

Whatever the cause of a false alert, it exposes innocent people to the inconvenience and humiliation of drug searches they have done nothing to justify. Now that the Court has said police need no special reason to bring in the dogs, provided they are otherwise complying with the law, such searches will become more common, and they need not be limited to routine traffic stops.