Police do not need a search warrant to test the blood alcohol level of an unconscious driver, the Supreme Court ruled Thursday.

The ruling was a victory for Wisconsin, upholding its law that says any person who drives on public roads automatically consents to a blood alcohol test, including someone who is unconscious. A total of 28 states have similar provisions in their implied consent laws.

The case arose from a 2013 incident involving Gerald Mitchell, who drove to the shore of Lake Michigan, took about 40 pills and drank vodka. Tipped off by a neighbor who feared Mitchell had driven away in a van, apparently drunk and suicidal, police arrived to find him belligerent and unsteady on his feet. After putting him in a holding cell, they decided to take him to a hospital, where they directed medical personnel to draw his blood. It showed an alcohol level of .22, far above Wisconsin's legal limit of .08.

When he was charged with drunken driving, he argued that the blood test violated the Fourth Amendment's protection against unreasonable searches because police did not get a warrant and he was incapable of consenting to the blood draw. Wisconsin state courts ruled against him, and the Supreme Court upheld those rulings.

The state said the ability to test the blood alcohol of any drivers, even unconscious ones, was important for protecting the roads.

"Drunk and drugged driving is an enormous public safety problem, and it is pernicious in Wisconsin," Wisconsin Attorney General Josh Kaul said. "Yet it is everywhere; it takes a terrible national toll. The states must have tools to combat it."