[JURIST] The Ohio Supreme Court [official website] ruled [opinion, PDF; press release] Tuesday that police must obtain a warrant before searching data stored in a cell phone, in the first ruling of its kind by a state high court. The court ruled 4-3 that a warrantless search of the contents of a suspect's cell phone violates the Fourth Amendment [text] prohibition against unreasonable search and seizure unless the search is necessary to protect the officers' safety or there are other exigent circumstances:

We hold that the warrantless search of data within a cell phone seized incident to a lawful arrest is prohibited by the Fourth Amendment when the search is unnecessary for the safety of law-enforcement officers and there are no exigent circumstances. Because the state failed to show that either of these exceptions to the warrant requirement applied, the search of Smith's cell phone was improper and the trial court was required to exclude from evidence the call records and phone numbers taken from the cell phone.

Greene County prosecutor Stephen Haller expressed disappointment [AP report] with the ruling and may appeal to the US Supreme Court.

Courts have struggled with how to apply Fourth Amendment protections to modern technology. Earlier this week, the US Supreme Court granted certiorari [JURIST report] in City of Ontario v. Quon [docket; cert. petition, PDF], in which the Court will consider whether a special weapons and tactics (SWAT) team member has a reasonable expectation of privacy in text messages sent to and from his SWAT pager, where the police department has an official no-privacy policy but a non-policymaking lieutenant announced an informal policy of allowing some personal use of the pagers. The US Court of Appeals for the Ninth Circuit ruled [opinion, PDF] that the SWAT team member does have a reasonable expectation of privacy and that a search of his text messages violated his Fourth Amendment rights.