A divided appellate court panel in Richmond, Virginia, ruled on Wednesday that citizens do not give up their privacy rights just because their mobile-phone providers know where to reach them.

The decision is the strongest assertion of the Fourth Amendment rights of mobile phone users out of three appellate court decisions on the matter, setting up a likely Supreme Court hearing.

“The tide I think is turning,” said Hanni Fakhoury, a senior staff attorney with the Electronic Frontier Foundation, which joined a friend-of-the-court brief in the case of Aaron Graham, a man convicted of armed robbery after his cell phone location information over seven months was obtained by the government from Sprint.

The Fourth Circuit Court of Appeals ruling rejected the “third party doctrine,” a legal theory that private information held by a company is not protected by the Fourth Amendment’s prohibitions against unreasonable search and seizure.

The ruling acknowledged the prevalence and advancement of technology in our lives. “People cannot be deemed to have volunteered to forfeit expectations of privacy by simply seeking active participation in society through use of their cell phones,” the court wrote.

“It’s great for us going forward,” says Nate Wessler, a staff attorney with the American Civil Liberties Union’s Speech, Privacy, and Technology Project.

“It’s a robust recognition of how much private information can be revealed through our cell phone records — doctor’s office visits, AA meetings … in the aggregate, it paints a strong picture of our lives.”

Wessler said a Supreme Court hearing on the case is now more likely.

In fact, the Fourth Circuit decision calls for it. The panel split 2 to 1, with one judge finding for the government.

Writing for the majority, Judge Andre Davis wrote: “If the Twenty-First Century Fourth Amendment is to be a shrunken one, as the dissent proposes, we should leave that solemn task to our superiors in the majestic building on First Street and not presume to complete the task ourselves.”