In Illinois v. Caballes, 543 U. S. 405 (2005), this Court held that a dog sniff conducted during a lawful traffic stop does not violate the Fourth Amendment's proscription of unreasonable seizures. This case presents the question whether the Fourth Amendment tolerates a dog sniff conducted after completion of a traffic stop. We hold that a police stop exceeding the time needed to handle the matter for which the stop was made violates the Constitution's shield against unreasonable seizures. A seizure justified only by a police-observed traffic violation, therefore, "become[s] unlawful if it is prolonged beyond the time reasonably required to complete th[e] mission" of issuing a ticket for the violation. Id., at 407.Justice Ginsburg wrote the opinion. Justice Thomas dissented, joined by Justices Kennedy and Alito.
The "only" in the last sentence is disputed in this case and remains open. The government contends that the officer did have an individualized basis for suspicion that the car contained drugs. Justices Thomas and Alito would affirm on that basis. Justice Kennedy agrees with the majority that the point is not properly before the Supreme Court because the Court of Appeals did not decide it.
Although the issue discussed in that Part [of Justice Thomas's dissent] was argued here, the Court of Appeals has not addressed that aspect of the case in any detail. In my view the better course would be to allow that court to do so in the first instance.