In the U.S., police who pull over suspected impaired drivers are permitted to ask the suspects to submit to a blood alcohol test. Often, this involves drawing blood from the driver and analyzing it for alcohol content (or THC).
Technically, police must get consent before sticking a needle into someone's arm for a blood test. But in some states, people can actually be charged with a crime for refusing a blood test. In North Dakota, for example, refusing a blood test subjects a driver to the same penalties as a DUI conviction. (In Washington, a blood test refusal results in a year-long suspension of your driver's license – which is not a criminal penalty, but rather the revocation of the privilege of driving.)
On Wednesday, oral arguments were presented at the U.S. Supreme Court about warrantless blood draws in DUI cases and whether criminalizing the refusal of these tests was a violation of the Fourth Amendment in the form of an unlawful, nonconsensual search.
According to a reporter who attended the hearing, the lawyer representing Danny Birchfield, who refused to take a blood test in North Dakota, did a solid job of defending his client's position that Birchfield shouldn't have been forced to take a blood test under threat of criminal penalties. In contrast, the two lawyers who stood up and tried to defend the warrantless blood tests performed so ineptly that the nine Supreme Court justices were openly laughing at them.
The Supreme Court won't render a decision for a few months. But based on the direction of the oral arguments, it appears that the justices will consider requiring police to at least get a warrant from a judge via telephone or electronic communication before drawing blood from a DUI suspect.