Can the police perform a blood test on an unconscious driver?

The U.S. Supreme Court has agreed to hear a case about the constitutionality of Wisconsin’s implied consent law, which is somewhat similar to that of Tennessee and many other states.

In both Wisconsin and Tennessee, drivers are deemed, by virtue of driving on the state’s roads, to have consented to chemical tests for intoxication. In both states, police officers can order these tests when they have reasonable grounds to believe the person was driving under the influence of drugs or alcohol. In both states, the driver can refuse such a test, although they will be charged with violating the implied consent law.

In the case before the court, a driver was pulled over for drunk driving in May 2013. A preliminary breath test indicated his blood alcohol content was at 0.24, three times the legal limit. A police officer arrested the man and took him to a hospital for a blood test.

On the way, the man fell unconscious. Attempts to rouse him at the hospital failed. The police officer directed the hospital to draw his blood anyway, even though Wisconsin law requires DWI suspects to be given an opportunity to refuse the test.

The problem with this is that the Supreme Court ruled in a case called Missouri v. McNeely that police need a warrant before they can draw blood from DUI suspects. The court reasoned that blood tests, unlike breath tests, are quite intrusive. Performing them without a warrant, in the absence of a legitimate emergency, violates the Fourth Amendment’s prohibition on unreasonable searches and seizures.

Yet the Wisconsin Supreme Court ruled that the state’s implied consent law only requires the officer to have probable cause to believe the suspect is impaired — not an actual warrant — before a blood test can be ordered. Can that court mean that its implied consent statute eliminates the need for a warrant that the U.S. Supreme Court has said is required by the constitution?

Tennessee’s implied consent statute under T.C.A. section 55-10-406 does have a provision that Wisconsin’s does not. When a suspect is unconscious or otherwise incapable of refusal, the test shall not be given unless law enforcement has obtained a warrant or one of the exigent circumstance exceptions to a search warrant apply.

This case could clarify whether a warrant is required in states whose implied consent statutes appear to allow warrantless blood tests in certain circumstances. At least 29 states have laws with provisions that could be interpreted as allowing blood tests on unconscious suspects without a warrant.

Warrants are not difficult to obtain when the officer can show probable cause. Do you think a warrant should always be required before a blood test?

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