On April 21, 2015, the U.S. Supreme Court vacated an Eighth Circuit ruling allowing police to conduct drug-detecting dog sniffs following an otherwise completed traffic stop. In Rodriguez v. United States, 575 U.S. ___ (2015), the Court held that absent reasonable suspicion to investigate for drugs, a dog sniff conducted after the completion of a traffic stop constitutes an unreasonable seizure under the Fourth Amendment.
The facts of Rodriguez involved a motorist pulled over for driving on a highway shoulder in violation of Nebraska law. After questioning the motorist and his passenger and running a records check on the motorist, the officer issued a written warning. The officer proceeded to explain the contents of the warning, and when finished, asked the motorist if the officer could conduct a dog sniff. The motorist refused, and the officer instructed the motorist and his passenger to exit the vehicle. After seven to eight minutes elapsed, a second officer arrived and conducted a dog sniff, which revealed methamphetamines.
The motorist was indicted on one count of possession with intent to distribute, and moved to have the evidence suppressed. The magistrate judge rejected the motion, and both the district court and Eighth Circuit affirmed on the grounds that a seven-to-eight-minute delay constituted a de minimis intrusion on the motorist’s Fourth Amendment rights.
Writing for a 6–3 majority, Justice Ginsburg vacated the Eighth Circuit’s decision. The Court focused on the officer’s own admission that no reasonable suspicion existed to initiate a dog sniff once the officer had issued the written warning. The Court made clear that absent reasonable suspicion, a traffic stop may only last as long as necessary to investigate the traffic infraction for which the stop was made. While police may conduct ancillary investigations to ensure safety, such as checking a driver’s license, running a records check, and inspecting a registration and proof of insurance, the Court noted that dog sniffs lack a close nexus to any such safety issue. Therefore, conducting a dog sniff absent reasonable suspicion deviates from the mission of the stop.