The Fourth Amendment of the U.S. Constitution guarantees our right to be free of unreasonable, warrantless searches and seizures — most of the time. There is an exception: If law enforcement has probable cause to believe that evidence of wrongdoing will be removed or destroyed in the time it takes to obtain a warrant, the emergency conditions may justify a search and seizure without a warrant. The exception is called the exigent circumstances doctrine.

Two years ago, the U.S. Supreme Court weighed the arguments in a case that pitted a man suspected of driving drunk against a Missouri law. The issue was not whether the plaintiff had been drinking. Rather, the court was asked to decide if the exigent circumstance doctrine applied to blood or urine tests taken — without consent and without a warrant — from detainees suspected of driving drunk.

The court said no. The exigency at hand — the natural metabolization of alcohol in the bloodstream would lead to the destruction of critical evidence that the driver’s blood alcohol content exceeded the 0.08 percent limit — did not present enough of an emergency to justify a warrantless search.

However, the court did not say that these tests were strictly unconstitutional. Police must apply the rule on a case-by-case basis, taking the “totality of the circumstances” into consideration, the court said.  

One of the most important circumstances, of course, is the passage of time. If there is enough time to get a warrant before the alcohol in the detainee’s bloodstream dissipates, then the police must get a warrant. The court did not explain how police were to judge how long was long enough.

Even if the ruling did not necessarily change the way the police operate, the case put Minnesota on notice that its implied consent law was on shaky ground. We’ll explain more in our next post.


Minnesota Public Radio, “MN Appeals Court: Cops need warrant for DUI blood test,” Bob Collins, Oct. 13, 2015

CNN, “Supreme Court rules against police in drunk driving case,” Bill Mears, April 17, 2013

Get In Touch
The use of the Internet or this form for communication with the firm or any individual member of the firm does not establish an attorney-client relationship. Confidential or time-sensitive information should not be sent through this form.