Privacy is a squishy concept, one that constantly evolves with the times—and with changing technologies. Advances in how we store and communicate information shift expectations around what we can keep to ourselves, and what the rest of the world is able to know. The disruption of established privacy norms is also nothing new: People were concerned when the postcard came out, for example, because they believed mail should be private.

Still, there's a growing sense that our privacy is more vulnerable now than ever before. The technologies and devices we consider essential to modern life also create an exhaustive record of where we go, who we interact with, how we entertain ourselves, and more. The consequences of that come into sharp focus when we learn, as we have over the past several years, how often corporations fail to safeguard our most sensitive information, or that the government is secretly spying on us.

There are measures you can take to lock down your own data, but broader protections may require new legislation or even reimagining our constitutional rights for the digital era; after all, the Fourth Amendment's protection against "unreasonable" searches and seizures leaves significant room for interpretation. The push for more privacy has been gaining momentum. Now the question is whether the courts, the federal government, or the states will step in to protect our privacy. Its future is still up for grabs.

A Major Win

The Supreme Court handed privacy advocates some good news in June with Carpenter v. United States. In a 5-4 decision, it ruled that the government generally needs a warrant to get cell site location records, which are automatically generated whenever a mobile phone connects to a cell tower. In the opinion, chief justice John Roberts acknowledged the necessity of cell phones for modern life, as well as the powerful surveillance capabilities they have.

The biggest question is whether Carpenter is merely a flash in the pan or the start of a total overhaul of the Fourth Amendment.

The decision was a victory for proponents of reforming constitutional law for the digital age, especially Justice Sonia Sotomayor, who was part of the majority. But Roberts was also careful to rule narrowly, meaning that Carpenter’s protections extend only to cell site location information and not to any other type of data, such as emails, text messages, and browsing histories.

“The Carpenter decision, it’s kind of an unsatisfying one I think, because it still leaves open so many questions. The majority’s rationale is a little all over the place,” says April Doss, a data privacy and cybersecurity lawyer who worked at the National Security Agency for years. “It still leaves open a ton of questions for the future about how this approach might apply to other technologies.”

The Supreme Court could clarify its position by taking on more cases. For example, the justices have yet to address whether Stingrays—the powerful surveillance devices that behave like fake cell phone towers—are constitutional. But it's not clear there's a desire in the court to take on such projects.

For one, Carpenter was a divided, 5-4 ruling that took the justices a significant amount of time to deliberate. Another problem is that if the Supreme Court issues a ruling too broad, it risks impeding an ongoing investigation that relies on electronic surveillance. And there are plenty of obstacles cases need to overcome just to get to that point.

"The courts realize that they're just stepping through a minefield here, and they don't even know what the potential landmines are," says Joshua Matz, a former clerk to justice Anthony Kennedy and the coauthor of Uncertain Justice: The Roberts Court and the Constitution.