Updated:
June 27, 2016

Whether states may criminalize a driver’s refusal to consent to a warrantless blood, breath or urine test for alcohol after a drunk driving arrest.

In 2013, the Supreme Court held in Missouri v. McNeely that the Fourth Amendment bars warrantless blood tests in drunk driving cases absent exigent circumstances beyond the normal dissipation of alcohol in the blood.  The issue in this case is whether a state can criminally prosecute a driver for exercising his Fourth Amendment right to refuse consent.  The ACLU argues in an amicus brief that the assertion of a constitutional right can never be a crime, and that the government cannot avoid this basic rule by treating the issuance of a driver’s license as a blanket consent to all future blood, breath, or urine testing without a warrant. 

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