In April the United States Supreme Court handed down its decision in Missouri v. McNeely and held that, when a person is unwilling to give a blood sample, a warrant is necessary. The Court ruled that the Fourth Amendment requires that a court issue a warrant if law enforcement wish to draw a person’s blood because in run-of-the-mill DWI/DUI cases the exigency exception to the warrant requirement does not apple. Missouri had argued that the fact that blood alcohol levels dissipate as time passes created such an exigency, however 5 justices, including Justice Sotomayor disagreed.
Previous case law has influence the typical procedure. When they suspect a driver of DWI/DUI, law enforcement will often try to extract their blood to show intoxication. To do so, they generally take the driver to a medical facility where a phlebotomist or other medical professional will conduct the blood draw. From the viewpoint of the state, the obvious and unavoidable delay in time creates a per se exigency which should allow the state to bypass the Fourth Amendment’s warrant requirement where a search or seizure (here, a search) is conducted by law enforcement.
The Court, in disagreeing with Missouri, instead held that a totality of the circumstances test would be the future guide as to whether a warrant was required before a blood draw. In its ruling, the Court did leave open the possibility of circumstances where an exigency may arise. In fact, the ruling specifically pointed to the procedure of obtaining a warrant, and the time lapse involved, as possibly creating that exigency. All in all, a ruling favoring the defense side of things, however, the holding created a fact-based inquiry into each course of events, which allows the state leeway to act without a warrant when it feels the need to do so.