Drunk driving is a public menace, and the nation is better for efforts to crack down on it. But motorists arrested for driving under the influence, like other people accused of crimes, have constitutional rights that police must respect — including the right to be free from unreasonable searches and seizures.
The Supreme Court reaffirmed that principle last week when it refused to give police blanket authority to draw blood from suspected drunk drivers without first obtaining a search warrant based on probable cause. Police in California and elsewhere are now on notice that, except in truly exigent circumstances, a warrant is necessary.
In a 1966 ruling, the court had upheld the taking of blood evidence without a warrant because the police officer in that case might reasonably have believed that the evidence of intoxication would have dissipated by the time he could obtain one. In the case decided last week, the state of Missouri had asked the court to establish a flat rule that warrants are unnecessary because of the danger that blood evidence would degrade.
By an 8-1 vote, the justices refused to carve out such a broad exception. In the leading opinion, Justice Sonia Sotomayor said that the legality of warrantless blood drawings should be evaluated based on "the totality of the circumstances." In a concurring opinion, Chief Justice John G. Roberts Jr. proposed a more detailed test: A warrant is unnecessary when "there is a compelling need to prevent the imminent destruction of important evidence, and there is no time to obtain a warrant." The "totality of the circumstances" test may not be crystal clear, but the practical effect of this decision will be to encourage police to seek warrants and to press magistrates to be available to provide them in a timely and efficient way. Sotomayor noted that a majority of states already allow police and prosecutors to apply for warrants electronically or by radio or telephone.