No Warrantless Blood Tests in DUI Stops, Says Supreme Court

Police officer administering a fielf sobriety test


Suspicion of driving under the influence is not grounds in and of itself for police to draw blood from a suspect without first acquiring a warrant, the Supreme Court ruled today.

In Missouri v. McNeely, the Court upheld a Missouri State Supreme Court ruling that police could only take a blood test without a warrant in an emergency or under exigent circumstances. A person’s blood alcohol content naturally dropping over time does not count.

“The question presented here is whether the natural metabolization of alcohol in the bloodstream presents a per se exigency that justifies an exception to the Fourth Amendment’s warrant requirement for nonconsensual blood testing in all drunk-driving cases,” Justice Sonia Sotomayor writes in the opinion. “We conclude that it does not, and we hold, consistent with general Fourth Amendment principles, that exigency in this context must be determined case by case based on the totality of the circumstances.”

The decision was split, with five justices signing onto a majority opinion, others concurring in part and only Justice Clarence Thomas completely dissenting.

The Supreme Court in 1966 decided in Schmerber v. California that warrantless blood tests were permissible but only when the circumstances called for it because of potential destruction of evidence. Today’s ruling effectively reinforces the Schmerber decision without broadening it.


DUI Enforcement

The case stemmed from the 2010 police stop of Tyler G. McNeely, who was pulled over for speeding but refused a breathalyzer or blood test though he exhibited other signs of intoxication. Missouri police took his blood anyway, without waiting for a judge’s ok. No good, the trial court decided — taking blood counts as a search, which is protected under a citizen’s Fourth Amendment rights. 

The state argued that the nature of BAC dissipation counted as an emergency when it could take up to two hours to rouse a judge for a warrant, stating “Although the dissipation rate will vary from person to person, one simple fact cannot be refuted — during a drunk driving investigation the best and most probative evidence of the crime is being lost at a significant rate.”

However, the Supreme Court noted that warrants can usually be obtained fairly quickly and efficiently. Furthermore, the opinion says, states have plenty of tools at their disposal to enforce DUI laws even without warrantless blood draws, including implied consent rules mandating that a driver automatically loses his or her license on refusal to take a BAC test.

Chief Justice John Roberts suggested that blood could be drawn automatically if a warrant could not be obtained in a specific amount of time; however the majority rejected any kind of uniform rule or guide.

Steven B. Epstein

Had the court ruled in favor of Missouri, it could have given police carte blanche to draw blood from anyone pulled over for DUI with no warrant. That, the justices decided, was going too far.

“The application for warrant process is a check on the system,” says Steven B. Epstein, a DWI attorney and partner with New York firm Barket, Marion. “You don’t want to give unbridled authority to law enforcement.”

Instead, if an officer does take a warrantless blood test, the court will get a chance to decide after the fact if it was justified. “Every case has its own fact patterns,” Epstein says. “Was there an opportunity to take a breath sample first? Did anyone need to be taken to the hospital?”

“It’s not that you can’t, with exigent circumstances, do this, but the fact that it’s a DWI case itself is not sufficient,” the attorney says. “Go get your warrant.”

Tagged as: , , , , , , , ,