When will a search warrant be required to obtain a blood test for blood alcohol content?

Brennan J., giving the majority judgment, affirmed the convic­tion, relying principally on the judgment of the court in Breithaupt v. Abram. In dealing with the argument relating to the Fourth Amendment, Brennan J. emphasized that the purpose of the Fourth Amendment is to protect “human dignity and privacy” and does not permit searches “involving intrusions beyond the body’s surface” on “the mere chance that desired evidence might be obtained”. He stated that search warrants are ordinarily required for searches of dwelling-houses and “… absent an emergency, no less could be required where intrusions into the human body are concerned” (p. 919). He said further at pp. 919-20: The officer in the present case, however, might reasonably have believed that he was confronted with an emergency, in which the delay necessary to obtain a warrant, under the circumstances, threatened “the destruction of evidence” … We are told that the percentage of alcohol in the blood begins to diminish shortly after drinking stops, as the body functions to eliminate it from the system. Particularly in a case such as this, where time had to be taken to bring the accused to a hospital and to investigate the scene of the accident, there was no time to seek out a magistrate and secure a warrant. Given these special facts, we conclude that the attempt to secure evidence of blood-alcohol content in this case was an appropriate incident to petitioner’s arrest.