Dennys Rodriguez was pulled over by highway patrol for veering onto the shoulder, which is unlawful in Nebraska. The officer checked Rodriguez’s license, registration, insurance, and for outstanding warrants. He issued a warning and gave back the documents—but then asked permission to walk his drug-sniffing K-9 around the car. Rodriguez said no. The officer nevertheless took his dog around the car; the dog alerted to the presence of drugs. A search of the car turned up a bag of methamphetamine.
The Supreme Court ruled that the drug sniff violated the Fourth Amendment. The Court said that a traffic stop may last only as long as necessary to accomplish the mission of the stop. The officers mission when he pulled over Rodriguez was to address the traffic infraction. Once he accomplished that objective, the mission was over, and so was his authority to detain Rodriguez. The officer’s prolonging the stop to lead his dog around the car therefore violated Rodriguez’s Fourth Amendment right to be free from unreasonable searches and seizures.
This ruling is somewhat unusual, as the trend in recent years has been for the Supreme Court to rule against individuals claiming Fourth Amendment violations.