Police cannot use drug-sniffing canines outside a suspect’s residence without first obtaining a warrant, the U.S. Supreme Court ruled this week.

The ruling (pdf), which was closely split at 5-4, came in a case out of Florida where, in 2006, a drug surveillance team of Miami-Dade Police detectives and Drug Enforcement Agency agents employed a trained dog to sniff around the property of Joelis Jardines. After the dog signaled to his handlers that illegal drugs were nearby, the police obtained a court order to search inside Jardines’ home, which turned out to have marijuana plants growing inside.

Jardines was apprehended as he ran out of his home to escape the police. Miami-Dade authorities confiscated 179 marijuana plants from the house, which they estimated to have a street value of more than $700,000.

Jardines—who was charged with drug trafficking and grand theft for stealing electricity for his enterprise—challenged his arrest on grounds that the use of the drug-detecting hound on his property without a warrant constituted a violation of the Fourth Amendment, which protects against illegal searches.

The case went to the Florida Supreme Court, which ruled the evidence against Jardines was inadmissible because police should have obtained a judge’s permission to check around outside the home.

The state then appealed to the U.S. Supreme Court, which agreed with the Florida high court.

“The police cannot, without a warrant based on probable cause, hang around on the lawn or in the side garden, trawling for evidence and perhaps peering into the windows of the home,” Justice Antonin Scalia said for the majority. “And the officers here had all four of their feet and all four of their companion’s, planted firmly on that curtilage—the front porch is the classic example of an area intimately associated with the life of the home.”

The Supreme Court had previously ruled in favor of dog-sniffing searches, including cases in which dogs caught the scent of drugs in airport luggage, a package in transit, and at traffic stops.

Although the drug-sniffing dog, Franky, lost this most recent Supreme Court case, he holds an impressive resume. He has sniffed out 2.5 tons of marijuana, 80 pounds of cocaine, and millions of dollars in cash during the course of his career with the police department. He has since retired.

-Noel Brinkerhoff, Danny Biederman

To Learn More:

Drug-Sniffing Dogs Need Warrants Outside House (by Barbara Leonard, Courthouse News Service)

Drug Dog's Sniff Is An Unconstitutional Search, Rules U.S. Supreme Court (by Jesse J. Holland, Associated Press)

Divided Supreme Court Hinders Cops’ Use of Drug-Sniffing Dogs (by David Kravets, Wired)

U.S. Supreme Court Opinion in the Case of Florida v. Jardines (pdf)

Lawsuit Challenges Effectiveness of Drug- and Bomb-Sniffing Police Dogs (by Noel Brinkerhoff, AllGov) 

Supreme Court Unanimously Rejects Obama Administration on Warrantless GPS Tracking (by Noel Brinkerhoff, AllGov)