Return of the Dragnet

The U.S. government says it has the right to track your cellphone’s every movement. Will the Supreme Court agree?

As Americans have adopted new technologies to make life more efficient, the government has devised ways to use that technology to curtail the Fourth Amendment.


The Supreme Court has a fraught relationship with technology. Can you blame it? The Bill of Rights predates even the most basic modern technology—telegraphs and motion pictures would utterly befuddle its drafters. Yet the court often looks to the past when asked to determine what rights we hold today. And so the justices wind up wondering what James Madison would think about video games or whether George Mason would compare a GPS tracker to a very tiny constable.

On Wednesday, the court will consider a monumental clash between technology and privacy in Carpenter v. United States. The case presents a thorny constitutional question: Under the Fourth Amendment, can law enforcement seize and search cellphone records that reveal the user’s location over 127 days? The government argues that it can, asserting that Americans have no right to privacy in the records they convey to third parties. But that claim is clearly inconsistent with contemporary technological developments—your cellphone is constantly shedding information that goes right to third parties, whether you want it to or not. And if the justices accept this flimsy argument, they will allow the government to create a dangerous new rule that subverts constitutional limitation on surveillance.

The Department of Justice’s Carpenter brief creates the impression that the Fourth Amendment was written to admonish Americans not to let other people get ahold of our sensitive information. It wasn’t. The Fourth Amendment places restraints on law enforcement, preventing the authorities from abusing their power in pursuit of criminals. It bestows upon “the people” a right “to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures”—meaning police must typically obtain a warrant from a neutral magistrate by demonstrating probable cause of criminal activity. A key purpose of the amendment was to outlaw general warrants, which gave officers vast discretion to search and seize whatever and whomever they wanted without any showing of suspicion of criminal activity.

As Americans have adopted new technologies to make life more efficient and better connected, the government has devised ways to use that technology to curtail the Fourth Amendment. The Supreme Court has generally indicated that the government cannot use these technologies to shrink our rights. In the age of originalism, this approach frequently requires an 18th-century solution to a 21th-century problem. The court has held, for instance, that the use of a thermal-imaging device on a home is similar to a physical intrusion in 1791, and the placement of a GPS device on a car is analogous to a founding-era trespass.

But this mode of analysis gets murky when it comes to data. In 1791, if you actively handed your private papers to somebody else, you likely recognized that they were no longer truly private. In 2017, our devices are constantly and passively churning out data to different companies, and we tend to view that data as private. Yet the court has consistently held that information voluntarily turned over to third parties does not receive Fourth Amendment protection. Thus law enforcement does not need a warrant to search business records, or capture every number dialed on a telephone, because a suspect has no reasonable expectation of privacy in information knowingly provided to a bank or phone company. Or at least, he didn’t in the 1970s, when those cases were decided. Carpenter gives the court an opportunity to revisit that question to determine whether this “third party doctrine” should apply to cell site location information.

The government believes that it should, insisting that anybody who wants to carry around a cellphone—so, almost everyone—must accept the reality that law enforcement can track your movements without a warrant based on probable cause. Its brief touts the existence of a putative safeguard, the Stored Communications Act, which requires the government to put forth “specific and articulable facts showing that there are reasonable grounds to believe that” the data sought “are relevant and material to an ongoing criminal investigation.” Why should the courts force law enforcement to get a warrant, the government muses, when Congress has already “struck a balance” preventing the police from inspecting a truly innocent person’s every movement?

There are, in fact, two reasons. First, the SCA creates a standard that is actually lower than the probable cause needed to obtain a warrant. So if a police search of cell site location information is truly a search under the Fourth Amendment, the SCA is not sufficient to protect the right to privacy. Second, the government’s argument raises a chilling possibility: If Congress repealed the SCA tomorrow, law enforcement could access every American’s cell site info in a snap. The courts could place no meaningful limits on the resulting dragnet, because the government’s search of our every movement poses no Fourth Amendment concerns.

In other words, a bad ruling in Carpenter could take us right back to the era of general warrants—only now, the government can collect a colossal amount of data without even entering your home. It can track your movements with startling specificity for lengthy periods of time; AT&T, for example, keeps your data for five years. So long as law enforcement can present facts that create “reasonable grounds” to believe that the data is relevant to an investigation, it can use your cell site location information to glean extraordinarily personal facts. By scrutinizing your movements alone, the government may be able to learn about your religion, profession, politics, health, family life, and sexual practices. Don’t like it? the government is saying. Then don’t use a cellphone.

The Fourth Amendment does not force Americans to live their lives off the grid if they wish to retain a semblance of privacy. Cell site info is categorically distinct from mere business records or phone numbers, and certainly as revealing as many of the “papers and effects” that the framers believed were worthy of protection. To remain faithful to the Constitution, the Supreme Court should limit law enforcement’s access to the location data that our phones beam to third parties. If it does not, Carpenter may stand for the proposition that we surrender our constitutional rights when we participate in the modern world.

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.