In Missouri v. McNeely, decided on April 17th, 2013, the Supreme Court held that the police cannot force someone to give a sample of their blood during the investigation of a DUI/OUI operaing under the influence case without attempting to get a warrant, or explaining to the court why it would not have been possible to do so.
The ordinary legal rule about searches and seizures is that the police need a warrant for any search or seizure, except where an exception to that rule applies. For example, there are exceptions for cases where the police have a high degree of suspicion and where the only thing they are searching is a car (the 'automobile exception'). In this case, police cited the exception for cases where, if the police were required to get a warrant they could not respond in time to save the evidence they are seeking to obtain (the 'exigent circumstances exception.').
The argument the police made was that, if they had to take the time to get a warrant in cases where someone was arrested for driving under the influence, the time it would take them to get the warrant would allow the alcohol in that person's blood to dissipate. What the police were asking for was a rule that in every drunk driving case, they could draw the person's blood without having to get a warrant, because every drunk driving case posed the sort of 'exigent circumstances' that justified the exception.
The Supreme Court, in an opinion written by Justice Sotomayor, held that a generalized rule to govern the whole country in every DUI/OUI case was inappropriate. Instead, in each case where the police obtain a person's blood without consent, the state will have to demonstrate that it was impractical to get a warrant. It based this decision on the observations that blood alcohol dissipates at a relatively predictable rate, and given that police will have to transport the suspect to a medical facility, some delay is inevitable.
If you or someone you know has been charged with Operating Under the Influence (OUI) in Massachusetts, please contact my office immediately for a free and confidential consultation.