On June 24, 2006, Deputy Sheriff William Wheetley pulled over Clayton Harris in Liberty County, Florida for having expired tags on his truck. Harris was shaky and agitated; an open beer in his cup holder didn’t aid his case. Wheetley deployed his drug-detection dog, Aldo, for an open-air sniff around the vehicle. The dog “alerted,” which was enough cause for a search. The officer found 200 pseudoephedrine pills, 8,000 matches and other ingredients for cooking meth under Harris’s seats.

The case would have been open-and-shut if Aldo were trained to detect the scent of matches and Sudafed, but he wasn’t. Aldo may have alerted to residual odors, but dogs can’t be cross-examined, and no illegal drugs were found on Harris’s person. The state of Florida’s appeal of the suppression of evidence based on this fact has made it all the way to the Supreme Court, where oral arguments in Florida v. Harris were heard in October.

Historically, courts have upheld the right of police to use drug dogs, but there are no national regulations for their training or reliability. Although dogs are required to be “trained” and “certified,” those terms vary widely. For example, U.S. Customs uses a rigorous 12-week training course that requires dogs to demonstrate 100 percent accuracy to pass and graduates only half its canine candidates; the United States Police Canine Association requires 70 percent accuracy, and the National Police Canine Association requires only that dogs find three of four “hides” to pass certification. Other programs provide no certification standards, simply graduating dogs that “pass.”

Research shows that even with training drug dogs can be remarkably inaccurate: Studies from the Chicago Tribune, the University of California, Davis and the Australian government have found that currently operating canines have false alert rates of 56 percent, 85.5 percent and 79.8 percent, respectively. These results were consistent over time and mirror situations encountered by police departments daily.

Then there are dogs that aren’t trained to detect drugs at all: Nevada state troopers filed a lawsuit last June alleging their dogs were being trained to operate as “trick ponies,” providing false alerts via handler cues to facilitate illegal searches and seizures of property (including money).

During oral arguments in the Harris case, Supreme Court Justice Antonin Scalia asked, “What are the incentives here? Why would a police department want to use an incompetent dog?” It would seem so-called incompetent dogs provide all the incentive potentially corrupt police need.