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.
