Supreme Court recognizes digital age with win for cellphone privacy

Equifax and Facebook have tested the limits of our tolerance for corporate promises to protect our personal information, while the special counsel’s investigation into Russian influence in the last presidential election has confirmed the extent to which U.S. intelligence gathering begins at home.

But do not lament the death of privacy just yet. The Supreme Court decided in United States v. Carpenter that the Fourth Amendment protects cellphone location information shared with service providers. It may not seem like the greatest win, but Carpenter could lead to future rulings recognizing that individuals have legitimate privacy interests when the government seeks their personal information in digital form.

{mosads}The ruling harks back half a century to a case called Katz v. United States. There, the court famously held that the Fourth Amendment protects people and not places as against the government. So long as an individual expectation of privacy is reasonable, it is protected. The analysis would be contextual. Whether federal agents need to get a warrant to obtain personal information would not necessarily depend upon whether individuals could be observed or overheard by someone else.

The Framers, after all, were not worried about the secrets we shared with our neighbors in conversations over the back fence. They put the Fourth Amendment’s protection of privacy in the Constitution because they were worried about the government intruding, without any justification, on those conversations. Nonetheless, in cases decided after Katz and long before the dawn of the digital age, the court concluded that, if you voluntarily shared personal information with a third party, you lost any expectation that the information would remain private.

Thus, you had no privacy interest in the numbers you dialed once you shared that information with the phone company. It was an open question at the time whether this rule accurately reflected the way in which people lived and conducted themselves, but the rule was expanded to many situations in which we voluntarily shared information about ourselves and our business with third parties, including banks and doctors.

In Carpenter, the defendant challenged the application of the third party rule in the context of cellphone data that revealed his location whenever he made or received calls. Despite the fact that such information is shared with a wireless carrier, the court concluded it has not lost protection under the Fourth Amendment. Though the court made clear that its holding extends no further than this kind of information, it represents an important limit on the reach of the third party rule.

Indeed, think for a moment about how much information about yourself flows through the seemingly innocuous stream of location data. Using the information generated by cellphones and similar devices over just a few days, the government could paint a convincing portrait of nearly any person’s habits and preferences, eliminating the need for a warrant in all but the most exceptional circumstances.

Chief Justice John Roberts, writing for the majority in Carpenter, recognized that the third party rule, if extended to its logical end, would make our personal information vulnerable to government seizure with a simple request to your service provider to hand it over. Now government agents will have to secure a warrant to get that information. This is not a revolutionary holding. It simply calibrates the Fourth Amendment’s protection of personal information with the way we actually live today.

Lawrence Friedman is professor at New England Law in Boston, where he teaches courses in constitutional law and information privacy law.