Breath Tests Incident to Arrest are Reasonable but Prosecution for Refusing a Blood Test Goes Too Far

The U.S. Supreme Court waded into the murky waters of implied consent law this term in Birchfield v. North Dakota. The opinion it issued last week clarified important aspects of the relationship between chemical testing for impairment and the Fourth Amendment, but failed to distill a coherent theory of implied consent. Here’s what we know after Birchfield: Warrantless breath testing of impaired driving suspects is permissible under the Fourth Amendment as a search incident to arrest. A person who refuses to submit to such testing may be subjected to sanctions ranging from license revocation to criminal prosecution. Warrantless blood testing of impaired driving suspects is not permissible under the Fourth Amendment as a search incident to arrest. Thus, a warrant or a suspect’s consent is required to conduct such testing. A person who refuses to submit to such testing may not be criminally prosecuted for that refusal. Three cases were consolidated for oral argument and decision in Birchfield. Blood test refusal. In Birchfield v. North Dakota, the defendant was arrested for driving while impaired.  The officer advised him that North Dakota law required him to undergo chemical testing and that, if he refused testing, he could be criminally prosecuted. Notwithstanding the warning, Birchfield refused to let his blood be drawn. He was thereafter prosecuted for his refusal, a misdemeanor crime. The North Dakota Supreme Court affirmed his conviction. Breath test refusal. In Bernard v. Minnesota, the defendant was arrested for driving while impaired.  The officer advised him that Minnesota law required [...]