A federal appeals court in Atlanta has overturned a ruling that would have required authorities to obtain a warrant before collecting Americans’ cellphone location data, but privacy advocates, who are fighting similar legal battles across the country, say it won't be the final word.

The overturned decision, issued last year by a three-judge panel of the U.S. Court of Appeals for the 11th Circuit, found the no-warrant status quo for police acquisition of cellphone location data unconstitutional.

That decision, written by Judge David Sentelle, said police violated the Fourth Amendment rights of Quartavious Davis, convicted of committing a string of 2010 robberies, by acquiring his cellphone location data from a service provider without a warrant based on probable cause. Police instead used a court order based on a lower legal standard, saying the records were relevant to an investigation.

Sentelle, joined by the two other judges, leaned heavily on the 2012 Supreme Court decision that police need warrants for GPS tracking, and weeks after that victory for privacy advocates the Supreme Court protected arrested people’s cellphones from warrantless searches.

The 11-judge en banc panel in its ruling Tuesday, however, accepted the government’s long-standing reliance on the 1979 ruling in Smith v. Maryland, which allowed the warrantless seizure of a suspect’s phone call metadata held by a business. That case also is cited by the government as allowing the dragnet collection of all Americans’ phone records.

"The use of cell phones is ubiquitous now and some citizens may want to stop telephone companies from compiling cell tower location data or from producing it to the government," the majority ruling said. "Davis and amici advance thoughtful arguments for changing the underlying and prevailing law; but these proposals should be directed to Congress and the state legislatures."

The majority found even if Smith v. Maryland wasn’t applicable, the acquisition of the records was constitutional.

“At most, Davis would be able to assert only a diminished expectation of privacy in MetroPCS’s records” and the government’s acquisition of them would be reasonable under the Fourth Amendment in efforts to identify criminal suspects, they wrote.

George Washington University law professor Orin Kerr calls the alternative holding “a novel development of the law that cuts against a lot of practice and precedent” in an analysis of the ruling on the legal blog The Volokh Conspiracy.

“It’s way beyond this case, waters down Fourth Amendment protections, and is only likely to confuse other courts,” Kerr writes, suggesting it may prompt Supreme Court justices to accept the case.

David Oscar Markus, a defense attorney for Davis who argued the appeal, tells U.S. News he plans to appeal the case to the Supreme Court within 90 days.

“The reach of the majority opinion is breathtaking," he says. “Unfortunately, the majority is stuck in the early ‘80s when cellphones were the size of bricks and cost $3,000. The cases from that long-ago era aren’t helpful in today’s world.”

A feisty dissent from Judge Beverly Martin, supported by Judge Jill Pryor, made a similar point, suggesting courts establish Fourth Amendment protections for the vast amounts of information people share with new technologies.

“Under a plain reading of the majority’s rule, by allowing a third-party company access to our e-mail accounts, the websites we visit, and our search-engine history—all for legitimate business purposes—we give up any privacy interest in that information,” Martin wrote.

“And why stop there? Nearly every website collects information about what we do when we visit. So now, under the majority’s rule, the Fourth Amendment allows the government to know from YouTube.com what we watch, or Facebook.com what we post or whom we 'friend,' or Amazon.com what we buy, or Wikipedia.com what we research, or Match.com whom we date—all without a warrant. In fact, the government could ask 'cloud'-based file-sharing services like Dropbox or Apple’s iCloud for all the files we relinquish to their servers. I am convinced that most internet users would be shocked by this.”

Nathan Freed Wessler, a staff attorney at the American Civil Liberties Union who argued the Fourth Amendment dispute before the three-judge panel but was denied time before the en banc court, says the Supreme Court probably could cite a circuit split, albeit a narrow one, with the Philadelphia-based 3rd Circuit – which allows judges discretion to require warrants – if it’s motivated to act, and says the strident dissent may inspire them to take the case.