Future Tense

They Have Eyes Everywhere

Courts can’t keep up with police technology that tracks your location.

In the past, resource constraints meant that the government could only track the locations of a small group of people. Now it can do so for the entire population.


On Wednesday, the Supreme Court will take the long-overdue step of hearing arguments on whether law enforcement should have to get a warrant before tracking individuals’ locations using their cellphones. Its ruling in the case—Carpenter v. United States—could dramatically shift privacy law and provide important protections from overbroad surveillance. Unfortunately, given how long it takes for the courts to settle privacy questions and the rapid advancement of technology in the hands of law enforcement, a decision in Carpenter is unlikely to safeguard our location privacy.

Location often reveals incredibly sensitive information about us. It can show our religious views, our political activities, our medical conditions, our interactions with lawyers, and our most intimate sexual relationships and social associations. And the potential for government to mine these sensitive data by tracking our locations is all the more worrisome because it has become exponentially easier and cheaper in recent years. For example, according to research published in 2014 in the Yale Law Journal, it previously cost roughly $250 an hour to track someone on foot and $275 an hour to track them by car. Now, police can track an individual with a GPS tracking device for a mere 36 cents an hour. Cellphone tracking can be as cheap as 4 cents an hour. In the past, resource constraints meant that the government could only track and log the locations and activities of a small group of people. Now it can do so for the entire population.

With practical limits on ubiquitous surveillance disappearing, the only checks to preserve our private identities are legal limits. However, the courts have moved far too slowly to protect them.

The most important location-privacy case until this year was U.S. v. Jones, which involved police attaching a GPS tracking device to a car and monitoring it for weeks. The Supreme Court properly recognized the importance of protections against location tracking and ruled 9–0 that this GPS tracking required a warrant. But the court ruled in a manner that would let the problem fester. It made the trigger for the warrant requirement not location tracking itself but rather the physical attachment of the GPS device to the vehicle (although five justices did argue in concurring opinions that there was a more general right to location privacy).

This was a huge problem, because the GPS tracking at issue occurred in 2005, but by 2012, when the Supreme Court issued its ruling, this method had been largely replaced by the even more invasive tactic of cellphone tracking. And in the five years since the Jones decision, pervasive location tracking via cellphones has become more and more common. Law enforcement now issues hundreds of thousands of orders for cellphone location data, often without a warrant, compelling carriers to provide data that they have to collect for phones to function and communicate.

That takes us to Carpenter, where the court will finally take on the question directly: Does the Fourth Amendment require a warrant when the government uses a cellphone to track an individuals’ location? Hopefully—as my organization, the Constitution Project, recommended in its amicus brief—the answer will be yes. As Justice Sonia Sotomayor explained in Jones, the ability of government to stockpile sensitive information about its citizens could “alter the relationship between citizen and government in a way that is inimical to democratic society.” This risk holds whether location tracking—and the personal information it reaps—occurs via a GPS device, a cellphone, or any other method.

And it is those other methods that should make us worry when looking toward the future. Even if the Supreme Court issues a comprehensive rule requiring a warrant for cellphone location tracking, new tactics and technologies are emerging that could again allow law enforcement to circumvent rules and engage in pervasive location tracking. Two stand out as especially worrisome: aerial surveillance and facial recognition.

Aerial surveillance is by no means new, but emerging technologies are making it an unprecedented threat for location tracking. In Baltimore, the private company Persistent Surveillance Systems maintains Cessna planes that fly around the city, constantly ready to monitor any part of the area below at a moment’s notice. After receiving a signal from the ground, these planes’ camera operators can zoom in on an area close enough to identify an individual, then zoom back and follow an identified person as a dot across a city. In fact, Persistent Surveillance Systems boasts about its capacity to engage in location tracking, and the company is seeking to expand to other areas. And while owner and chief technical officer Ross McNutt insists his company will focus its efforts on crimes in progress and suspects rather than pervasive surveillance, it is offering a template that could be abused. In fact, one can argue that it already has been. During demonstrations after Freddie Gray died in Baltimore police custody in 2015, the FBI used aerial surveillance, flying its own planes and recording devices to log protesters.

And this is just today’s technology. Currently, a program like Persistent Surveillance System’s Cessna planes must zoom its cameras in to obtain precision viewing—such as a face or license plate—which means it has to stop filming the broad area across the city. In the future, the government need not choose between the two. The Department of Defense scientific branch Defense Advanced Research Projects Agency developed ARGUS-IS, a camera that can record with precision from 20,000 feet, capturing an area as broad as half of Manhattan with perfect resolution of everything within that field. If police obtain the ability to fly planes or drones with cameras as powerful as the ARGUS-IS over cities, it will essentially mark an end of anonymity in populated areas.

Aerial surveillance will be incredibly difficult for civil rights and civil liberties advocates to grapple with. It may seem reasonable to advocate for laws that would prevent fleets of drones with ARGUS-IS-powered cameras from flying over every city and suburb. But it would be challenging not to overreach into noncontroversial practices such as common police choppers. One solution here might be a “naked-eye rule,” whereby court approval is necessary for individuals looking out of a plane to use advanced video technology on aircrafts. Maybe other middle-ground measures will emerge. One thing is sure, though: The Supreme Court’s ruling in Carpenter will not resolve this question.

Just as problematic as unchecked aerial surveillance is the growing power of facial-recognition technology. Already, 1 in 2 American adults is in a law enforcement facial-recognition network, and 1 in 4 local or state police departments can run facial-recognition searches. And “real-time” facial recognition—meaning facial recognition that scans a crowd and instantly identifies individuals on any type of preprogrammed watch list—will allow police to track as many people as they want in an automated manner. Police closed-circuit TV already blankets Chicago and other cities. And police body cameras, first hailed for bringing transparency, will expand law enforcement’s access to real-time video footage to an unprecedented degree. America’s largest body-camera vendors are actively working to incorporate facial recognition that could identify individuals, which—if widely used—could basically turn every beat cop into part of an automated system of identifying and logging the activities of every individual he or she passes.

Given the seriousness of these threats to privacy, we cannot follow the same slow pattern we did for Jones and Carpenter. We cannot accept five or 10 years of location tracking that is even more pervasive than anything we’ve encountered before while we await the courts to sort it out. No matter how the Supreme Court rules on the Carpenter case, Congress and state legislatures need to begin taking the threat of pervasive location tracking—by whatever means—far more seriously. Sensitive information is sensitive no matter what tool is used to scoop it up en masse.

This article is part of Future Tense, a collaboration among Arizona State University, New America, and Slate. Future Tense explores the ways emerging technologies affect society, policy, and culture. To read more, follow us on Twitter and sign up for our weekly newsletter.