What was the ruling in Missouri v. McNeely regarding blood tests?

The ruling in Missouri v. McNeely established that, in most circumstances, law enforcement must obtain a warrant before conducting blood tests for blood alcohol content in DUI cases. The court emphasized that while the natural dissipation of alcohol in the bloodstream can create a situation that might seem exigent, this does not automatically negate the requirement for a warrant.

In this case, the Supreme Court ruled that exigent circumstances must be evaluated on a case-by-case basis. Therefore, unless there are specific extraordinary circumstances that justify immediate action without a warrant, law enforcement officers are required to first secure a warrant to conduct blood tests. This ruling reinforces the constitutional protections against unreasonable searches and emphasizes the importance of obtaining judicial oversight in the process of collecting evidence in DUI cases.