In 1966, the U.S. Supreme Court upheld in Schmerber v. California a warrantless blood test of a drunken-driving suspect because of exigent circumstances. It found that “the delay necessary to obtain a warrant, under the circumstances, threatened the destruction of evidence.”
On April 17, 2013, the same court suppressed the warrantless blood test of a similar defendant, ruling in Missouri v. McNeely that in drunken-driving investigations, “the natural dissipation of alcohol in the bloodstream does not constitute an exigency in every case sufficient to justify conducting a blood test without a warrant.”
