When does a K-9 cop need a warrant for his nose?

Suppose you’re pulled over by police for a traffic violation. Is it legal for the officer to make you wait a few minutes after writing you a ticket so a backup officer can arrive and allow the first officer’s police dog to sniff for drugs? That was the question before the U.S. Supreme Court late last month.

In 2012, a Nebraska policeman pulled over Dennys Rodriguez for veering off the highway. The officer checked his license and registration, asked a few questions, and issued a written warning. During that time, the officer observed a nervous passenger who pulled his hat down over his eyes. He smelled overwhelming air freshener, which often is used to mask drug odors. Now suspicious, the officer asked permission to have his canine partner sniff around the car.

Rodriguez said no. The officer ordered Rodriguez out of the car and called for backup. Afterward, the dog sniffed the car and signaled to officers that drugs were in it. A search produced a bag of methamphetamine. It took about eight minutes after writing the ticket for the dog to do its investigation.

Rodriguez’s attorney, Shannon O’Connor, wants the meth evidence thrown out. He argued those eight minutes were a Fourth Amendment violation—an unreasonable search and seizure. The traffic stop should have ended when the officer issued the warning for veering off the road, O’Connor said.

But Justice Samuel Alito saw futility in that reasoning.

“If we hold that it’s OK to have a dog sniff so long as it’s before the ticket is issued, then every police officer, other than those who are uninformed or incompetent, will delay the handing over of the ticket until the dog sniff is completed,” he said.

Ginger Anders of the Solicitor General’s office argued for “reasonable analysis” on a case-by-case basis.

“We don’t want officers to have to make finely tuned judgments in the moment about whether the next question he wants to ask is sufficiently related to the traffic mission or not,” Anders said. She argued the delay was within legal limits for searches and minimal. The justices and lawyers went back and forth about what constituted a “minimal” or “reasonable” delay, but Justice Sonia Sotomayor brought the argument back to constitutional principles.

“We can’t keep bending the Fourth Amendment to the resources of law enforcement,” she said. “Particularly when this stop is not incidental to the purpose of the stop. It’s purely to help the police get more criminals. … Then, the Fourth Amendment becomes a useless piece of paper.”

A “search” is a legal trigger requiring further analysis about probable cause, reasonable suspicion, and whether a search warrant is needed. If a dog sniff is not considered a “search,” then none of that other analysis is needed. And here the law is unclear.

Earlier Supreme Court rulings said dog sniffs in public places aren’t searches because there is no reasonable expectation of privacy in public. But just last term, the court said using dogs to sniff for drugs on someone’s front porch is a search that first requires a warrant. Another case said if a police dog already is on the scene of a traffic stop and alerts officers to drugs, that’s probable cause to search and no warrant is needed. A decision on this case, later this year, could clear up the practical limits of using man’s best friend to catch criminals.

Listen to Mary Reichard’s “Legal Docket” on The World and Everything in It.