Before we delve into the specifics, let’s clarify what a search warrant entails. Essentially, it’s a judicial authorization that allows law enforcement to conduct searches and seize evidence, as long as such activities are founded on probable cause. Given the intrusive nature of a blood draw, one might assume a warrant requirement is always necessary, but this isn’t always the case.
The Supreme Court has determined that while breath tests, being less intrusive, do not require a warrant, blood draws generally do. However, there’s an exception: if obtaining a warrant would significantly hinder the collection of evidence, officers can bypass this requirement. Cases such as Missouri v. McNeely and Birchfield v. North Dakota have emphasized the need for law enforcement to secure a search warrant before conducting a blood test in DUI investigations. In essence, the Fourth Amendment directs officers to obtain a warrant for a blood draw whenever it’s reasonably possible to do so without compromising the efficacy of the search.