Nearly everywhere your cellphone goes in the world, it is tracked.

When you start or end a call, your cell provider logs a piece of data saying where your phone is in the world. When you send or receive a text, it logs the same kind of data. And every time you get a notification, it logs similar data again.

Of course this kind of tracking doesn’t just follow your cellphone. If you’re carrying your phone while it does all these things, then you are tracked, too.

This location data—officially called “cell-site location information,” or CSLI—has been the topic of legal controversy lately. Because your cell provider ultimately creates this information, it is subject to the “third-party doctrine,” a piece of legal precedent created by the Supreme Court in the 1970s. The third-party doctrine allows for the government to access information shared with a third party (like a bank or a phone company) without a warrant.

In other words, a police department or law enforcement agency can back-request historical CSLI whenever they want—and they don’t need a warrant to do so. This ease of access makes CSLI one of the most common forms of government surveillance: In 2015, AT&T alone received almost 60,000 requests for historical CSLI. (In order to track a cellphone in real time, police still need a warrant.)

The relative ease of this method strikes many privacy advocates as, well, inappropriate. After all, the Supreme Court ruled just a few years ago that attaching a GPS tracker to someone’s car requires a warrant—shouldn’t cellphones, which nearly everyone carries around already, be subject to the same protections? For the past few years, two of the country’s most prominent privacy advocacy groups—the Electronic Frontier Foundation and the American Civil Liberties Union—have encouraged the nation’s highest court to take up the CSLI issue. On top of everything else, it seems like a perfect cudgel to update the law around the Fourth Amendment, which protects against unreasonable search and seizure.

And it may well be—but it probably won’t happen this year. The full panel of the Fourth Circuit U.S. Court of Appeals affirmed this week that law enforcement does not need a warrant to access historical CSLI. The ruling closes the book on what had been the most hopeful case to change the law around the data. Last August, a smaller panel from the same court ruled that authorities did need a warrant. That ruling had created disagreement among the nation’s appeals courts—a “circuit split”—on the issue, creating an opening for the Supreme Court to swoop in and rule clearly about whether gathering CSLI required a warrant.    

But with this week’s decision, the opening has now closed. The Fourth Circuit joins three other federal circuits in affirming that CSLI collection does not require a warrant. (The Sixth Circuit ruled on this issue only last month.) Federal authorities working in Maryland, Virginia, West Virginia, and North Carolina can now comfortably gather this information without seeking a warrant first. (Local and state police in Maryland and Virginia are more limited by state law.)

The Fourth Circuit was clear that the third-party doctrine kept its hands tied on the issue.

“Supreme Court precedent mandates this conclusion,” writes Judge Diana Gribbon Motz, a Clinton appointee writing for the majority. “For the Court has long held that an individual enjoys no Fourth Amendment protection ‘in information he voluntarily turns over to a third party.’”

“The Supreme Court may in the future limit, or even eliminate, the third-party doctrine. Congress may act to require a warrant for CSLI. But without a change in controlling law, we cannot conclude that the Government violated the Fourth Amendment in this case,” she continues.

Orin Kerr, a professor of criminal procedure and computer law at George Washington University, said that it’s only a matter of time until the Supreme Court rules on the question.

Seven federal appeals courts and most of the 51 state superior courts have yet to decide on the issue, Kerr said. “This is an issue that is going to come up in every state and every circuit. There’s going to be at least one court that is going to buck the trend,” he told me. “All it takes is one.”

Once a single court challenges the third-party doctrine, the Supreme Court will almost certainly examine the issue fresh and not feel bound by precedent. “When it gets to the Supreme Court, the justices probably won’t care that most of the circuits said it was a search,” said Kerr.

That’s exactly what the EFF hopes will happen. “Now, more than ever, it’s clear that the only way to ‘assure preservation of that degree of privacy against government that existed when the Fourth Amendment was adopted’ is for the Supreme Court to revisit and overturn the third party doctrine,” writes Jennifer Lynch, a senior staff attorney at the organization. She calls on the Graham defendants to appeal to the Supreme Court.

But Kerr said that’s unlikely to happen—at least with this case. “This issue will live on, it’s gonna keep bubbling up,” he told me. “This is a long running story, we're just in the early chapters of it.”