The fact that the human body naturally metabolizes alcohol in the blood does not automatically constitute exigent circumstances for the Fourth Amendment search warrant exception.
In Missouri v. McNeely, 133 S. Ct. 1552 (2013), the U.S. Supreme Court held that whether an officer is permitted to require a blood test of a suspected drunk driver must be determined on a case by case basis. In the McNeely case, the defendant had refused to submit to a breathalyzer test after failing field-sobriety tests. The officer who pulled him over then took him to a hospital where a blood test was performed without McNeely’s consent or a search warrant.
McNeely filed a motion to suppress the results of the blood test, which had determined his BAC (blood alcohol concentration) was almost double the legal limit. The trial court granted his motion to suppress due to his lack of consent and a warrant, saying that the typical circumstances of the body processing alcohol did not qualify as exigent circumstances under the established Fourth Amendment exception. The trial court determined that there was no reason the officer could not obtain a warrant first. The Missouri Supreme Court affirmed the lower court’s decision.
The exigency exception “applies when the exigencies of the situation make the needs of law enforcement so compelling that a warrantless search is objectively reasonable under the Fourth Amendment.” Kentucky v. King, 131 S. CT. 1849, 1856 (2011).
The U.S. Supreme Court discussed how the metabolization of alcohol is a predictable process, and further how taking suspected drunk drivers to a place where a blood test can be performed requires time. In fact, likely the same kind of delay that would be necessary in order to obtain a search warrant. All of this was considered in the context of how technology enables officers to obtain warrants quicker and easier than ever before. In situations where true exigent circumstances do exist, the Court found that no warrant will be required. Trial courts will now have to decide on a case by case basis whether exigent circumstances exist in order for law enforcement to circumvent the warrant requirement when taking the blood of suspected drunk drivers to determine their BAC levels.