A full panel of judges at the Fourth US Circuit Court of Appeals has now overturned last summer’s notable decision by the standard trio of appellate judges, which had found that police needed a warrant to obtain more than 200 days’ worth of cell-site location information (CSLI) for two criminal suspects.
In the Tuesday en banc decision, the Fourth Circuit relied heavily upon the third-party doctrine, the 1970s-era Supreme Court case holding that there is no privacy interest in data voluntarily given up to a third party like a cell phone provider. That case, known as Smith v. Maryland, is what has provided the legal underpinning for lots of surveillance programs, ranging from local police all the way up to the National Security Agency.