When does the dog sniff go too far?

In 2005, the Supreme Court held in the Caballes case that the police can conduct a dog sniff on your car during a traffic stop. This time around, the Court asks a follow-up question: at what point during the traffic stop is the dog sniff prohibited by the Fourth Amendment?

The case is Rodriguez v. United States, decided on April 21. The Fourth Amendment prohibits unreasonable search and seizures. You cannot resolve Fourth Amendment cases simply by reading the Fourth Amendment; it tells us very little. To answer the question, you have to read the reams of case law that interpret the Fourth Amendment. All of our Fourth Amendment jurisprudence is judge-made.

The many cases interpreting the Fourth Amendment may seem a jumble, but there is a logic to them. The Caballes ruling is a good starting point for this case, but this case is not Caballes, because the facts are different. This time around, defendant was stopped after the driver jerked his car onto the shoulder and then back into the highway. The police checked the license and registration and ran a computer check on the driver. The officer gave the driver a warning ticket. So far, so good.

Moments later, not so good for the driver. Once the traffic stop had run its course and the officer gave the driver a warning, he got out the dog and gave the car an outside sniff. Of course, this being a challenge that reached the Supreme Court, the dog smelled drugs, the police seized the drugs and the driver's life suddenly went down the chute. The dog sniff phase of the stop lasted seven or eight minutes. Was the dog sniff legal?

It was not legal, because the traffic stop had run its course and there was no probable cause or reasonable suspicion for the police to think the driver had drugs in the car. Caballes dictates the result. Writing for a 5-4 majority that included Justice Scalia, the Notorious RGB writes that "In Caballes ... we cautioned that a traffic stop can become unlawful if it is prolonged beyond the time reasonable required to complete the mission of issuing a warning ticket." In another case, the Court said that "the seizure remains lawful only so long as unrelated inquiries do not measurably extend the duration of the stop." The Court in this case summarizes the state of the law: "An officer, in other words, may conduct certain unrelated checks during an otherwise lawful traffic stop. But ... he may not do so in a way that prolongs the stop, absent reasonable suspicion ordinarily demanded to justify detaining an individual."

The case is remanded to the lower courts to decide if the officer had reasonable suspicion to allow the dog to sniff the car. In dissent, Justice Thomas says there was in fact reasonable suspicion and that the defendant cannot assert any rights under the Fourth Amendment.