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.

Judge Koh also held the “third party doctrine” did not apply to this information. The “third party doctrine” holds that people do not have a reasonable expectation of privacy for information voluntarily given to a third party. By contrast, Judge Koh concluded, CSLI is not voluntarily provided because in order to consent to the government acquisition of CLSI, the cell phone user would have to read the privacy policy of “every service provider in the country.”

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 11^th Circuit’s ruling in U.S. v. Davis.