On Wednesday, the Fourth Circuit held, in United States v. Graham, that "the government’s warrantless procurement of [cell-site location information] was an unreasonable search in violation of Appellants’ Fourth Amendment rights." But unfortunately for Mr. Graham and his co-defendant, the court also held that the good-faith exception applied to law enforcement's conduct and affirmed the convictions.
The Fourth Circuit's holding in Graham creates a clear circuit split with the Fifth and Eleventh Circuits on whether acquiring cell-site location records is a search. And according to a post by Orin Kerr (which I recommend), it also "it also appears to deepen an existing split between the Fifth and Third Circuits on whether the Stored Communications Act allows the government to choose whether to obtain an intermediate court order or a warrant for cell-site records."
This is an issue that the Supreme Court may be taking up soon. Last week, the ACLU filed a cert petition on this issue in case from the Eleventh Circuit. So it might be sooner rather than later that this issue gets there. In other words, it is definitely something that should be litigated. If you have a case where the government obtained historic cell-site location information without a warrant, you should be filing a motion to suppress and using the decision in Graham as persuasive authority.