Mitchell v. Wisconsin

When a driver is unconscious and therefore cannot be given a breath test, the exigent-circumstances exception to the Fourth Amendment generally permits a blood test without a warrant.

Petitioner was arrested for driving while intoxicated. After he was unable to provide the standard second breathalyzer Petitioner was transported to the hospital for a blood test. Although unconscious upon arrival, a blood sample was taken and Petitioner was charged with the offense. Petitioner moved to suppress the results of the blood test, arguing it violated his Fourth Amendment right against warrantless searches. The trial court denied the motion to suppress based on Wisconsin’s implied-consent law. The appellate court certified the case for review. The Wisconsin Supreme Court affirmed based on the implied-consent law. The Supreme Court granted certiorari to decide whether a statute which authorizes a blood draw from an unconscious motorist violates the Fourth Amendment. The Supreme Court held that such a statute does not violate the Fourth Amendment reasoning that when breath tests are impossible, enforcement of traffic safety and drunk driving law depends upon the ability of law enforcement to obtain BAC blood draws. Blood draws from unconscious drivers fall into the exigent-circumstance exception to the Fourth Amendment protections because the ultimate goal is to prevent the destruction of evidence impossible to obtain in such circumstances without a blood draw.