We previously reported that government access to cellphone geographic information or CSLI without a warrant has become a vigorous debate between the government, defense attorneys, and the federal bench. In a lengthy opinion, Judge Lucy Koh of the Northern District of California joined those who held that the Fourth Amendment applies to CSLI. Prior to this ruling, the government contended that it need only meet the lesser “reasonable suspicion” standard set forth in the Stored Communications Act to obtain this data. Judge Koh rejected this analysis and, relying on the Supreme Court decisions concerning attaching a GPS device to a car (United States v. Jones) and searching mobile phones (Riley v. California), held that individuals have a reasonable expectation of privacy in the historical CSLI generated by the cellphones.
It is not clear if this ruling will be appealed by the government. If so, the Ninth Circuit may join the current circuit split about government access to this information. This circuit split, however, may be resolved by the U.S. Supreme Court, if it grants the certification petition that was just filed appealing the 11th Circuit’s ruling in U.S. v. Davis.