The Carpenter Decision: A Huge Step Forward for Privacy Rights but Major Problems Remain

Last week the Supreme Court issued a landmark decision in Carpenter v United States, which challenged the government’s warrantless acquisition of cellphone location data. The Court’s ruling that a warrant is required for the government to obtain historical location data will have a major impact on privacy rights, both in terms of immediate practical effects and expanding Fourth Amendment doctrine to respond to rapidly evolving surveillance technologies. But the Court also crafted a narrow ruling that needlessly left many issues unaddressed, with serious ramifications for our privacy rights for years to come.

In order to understand the magnitude of the Carpenter ruling, it’s important to note how frequent and invasive cellphone tracking is. As The Constitution Project noted in its amicus brief submitted for the case (which was cited in the decision), police make hundreds of thousands of demands for cellphone location data every year; by comparison, there are only several thousand wiretap orders per year. And location information is incredibly sensitive. It reveals everywhere we go, and as a result, can be used to deduce our personal and romantic relationships, political and religious views, medical histories, work activities, and a host of other intimate details about our lives. Placing a warrant requirement on this common surveillance tactic will have immediate benefits for hundreds of thousands of people who were being watched too easily, and prevent overbroad surveillance in the future.

Perhaps even more significant than its immediate impact is the basis for the Supreme Court’s decision. For years, many have argued that in the digital age, the Fourth Amendment should not be treated as merely building a legal wall between public and private spheres, but rather as a limit on the power government can obtain by stockpiling sensitive information about its citizens (a few good examples pioneering this concept come from are Orin Kerr, Daniel Solve, and Kevin Bankton and Ashkan Soltani). By declaring that “the [Fourth] Amendment seeks to secure the privacies of life against arbitrary power” and that “a central aim of the Framers was to place obstacles in the way of a too permeating police surveillance,” the Supreme Court established a powerful new doctrine that courts can apply to emerging technologies in the future.

And in embracing the notion that too much surveillance power in itself can trigger Fourth Amendment protections, the Supreme Court highlighted two important triggers in relation to location tracking.

First, the Court more generally accepted an idea it had previously discussed regarding cellphones in Riley v California several years ago: It concluded that “voluntarily” exposing one’s information—which generally means forfeiting privacy rights to that information—should be based on feasible actions for living in modern society, not the more broad standard of whether it is technically possible (but not at all reasonable) to avoid such actions. When looking at individuals’ choice to use cellphones, and the location data collection that comes with them, the Court described modern phones as “almost a feature of human anatomy” and concluded, “cell phones and the services they provide are such a pervasive and insistent part of daily life that carrying one is indispensable to participation in modern society.”

This will have major ramifications not just for other Fourth Amendment cases involving smartphones, but also involving a host of other technologies. From now on, the standard of “voluntarily” giving up data is not whether it was technically possible to instead live in a hut off the grid, but rather whether such data stems from a necessary action to participate in modern society. This will certainly impact legal arguments on web browsing, apps, and computers generally. It could even expand to use of cars, a necessity for many. And in the future a host of technologies—from Internet of Things devices to tools and services we can’t even imagine—will fall into this same bucket of not-truly-voluntary-choices that is now entitled to Fourth Amendment protections.

Second, the Carpenter ruling represents a huge leap forward for privacy rights in public. Traditionally information that the government could freely see was by nature not private, and not entitled to Fourth Amendment protections. But by saying that some surveillance power is simply too powerful to exist unchecked in a democracy, the Court upended this idea. Although some information may be freely visible to observe and catalog on an individual scale, we’re entering a new era where for the first time technology may allow the government to stockpile such data en masse. Carpenter established that at some point scale of collection matters more than availability of information on an individual basis.

We’ve reached that point for location data. As the Court notes, “With just the click of a button, the Government can access each carrier’s deep repository of historicalal location information at practically no expense.” This formally establishes as a Fourth Amendment protection an often-overlooked shield that I’ve described as critical to democracy: obscurity. Our location (and the activities and associations it reveals) has always been highly sensitive, but we’ve trusted our ability to blend into a crowd as sufficient protection. Carpenter holds that a police officer’s eyes are categorically different than sweeping electronic scans, even in public.

Achieving the right to privacy in public spaces is likely to have far-reaching implications for emerging surveillance technologies, from facial recognition to automated license plate readers to aerial surveillance. All these technologies threaten to permit dragnet surveillance of our activities and associations on as significant a scale as cellphone location tracking, perhaps even more so. Carpenter lays the foundation for challenging unchecked use of these technologies, and makes clear that just because surveillance is of public activities does not mean it can go unchecked.

But the most obvious potential expansion of this new protection for privacy in public is something the Supreme Court erred in not addressing as part of the Carpenter decision: cellphone tracking in real-time. The Court explicitly declared that it was providing a narrow ruling that only applied to a government demand for cellphone location data from the past, and was not taking on the question of whether ongoing location surveillance in real-time should require a warrant as well.

Putting off this question is illogical and will result in serious harms to privacy. There is no meaningful distinction between historical and real-time location surveillance. Real-time location tracking provides the same “intimate window into a person’s life, revealing not only his particular movements, but through them his familial, political, professional, religious, and sexual associations” that the Court found too sensitive to be freely collected in terms of historical cellphone location tracking. Real-time location tracking can occur at the same unacceptably broad scale. The Court correctly said that “cell phone location information is detailed, encyclopedic, and effortlessly compiled,” and this is equally true for historical and real-time tracking. There is no rational basis to say that your location information today should receive less protection than your location information from yesterday, but because the Supreme Court opted for an unnecessarily narrow ruling, real-time location surveillance will continue to occur without a warrant and will be fought over in courts for years to come.

Even worse, the Supreme Court’s decision to avoid taking on real-time cellphone tracking creates a perverse incentive for police to ramp up collection. Using IMSI catchers, devices that imitate cell towers and are commonly called “stingrays,” law enforcement can suck up all cellphone location data in a large radius in real-time. Sometimes the government even places stingrays on planes and sucks up data across an entire city. Since the government now needs a warrant to get historical cellphone location data from companies but lacks this mandate for real-time tracking, law enforcement may now want to use stingrays to collect and stockpile as much location data as possible, and then refer back to internal databases to avoid needing to go to courts to get a warrant. This cannot possibly be what the Supreme Court envisioned when it created new privacy protections in Carpenter. Congress should act immediately to close this loophole by establishing the same warrant standard for real-time cellphone tracking as the Court established for historical data, thereby removing incentives to engage in bulk collection for later use.

Another area the Court needlessly took too narrow an approach was on was how long cellphone location tracking can occur for before a warrant is required. In a footnote, the Court notes that the government argued that seven days should be the cutoff, and therefore “It is sufficient for our purposes today to hold that accessing seven days of CSLI [cell site location information] constitutes a Fourth Amendment search.” The main reason the Court did this appears to be a desire to avoid ruling in a way that would affect collection of “tower dumps,” a slightly different tactic where law enforcement collects data of every cellphone that pinged off a tower, revealing everyone who was in a given area over a short period of time. It is a shame that the Court would recognize that certain locations are extremely sensitive and reveal “the privacies of life,” but potentially leave them unprotected. And even if the Court wanted to avoid a ruling that would affect tower dumps without a case fully focused on that specific technology and its ramifications, tower dumps generally last for a number of hours, not days. The Court could have easily established a twenty-four-hour cutoff as the plaintiff requested without preemptively ruling on other location tracking techniques. This is another area where Congress should act to prevent the years of overbroad surveillance and litigation that will result because the Carpenter ruling was unnecessarily restrained.

The decision also featured four dissents, one from each Justice that did not sign on to the Opinion of the Court. Unfortunately, three of these dissents demonstrate that much of the Court is still troublingly out of touch with how modern surveillance affects our lives. Justice Kennedy argued that because cellphone location data is held by phone companies, individuals have no privacy right to that information. Similarly, Justice Thomas contends “By obtaining the cell-site records of MetroPCS and Sprint, the Government did not search Carpenter’s property.” And Justice Alito dismisses the idea of requiring a warrant for “the search of a third party’s property” as “revolutionary.” These arguments refuse to acknowledge the necessity of cellphones in modern life, and effectively tell the American public that the price of living in a 2018 world of technology is to live with an Orwellian 1984 government.

Justice Kennedy at least seems to understand the flaws of fully applying this concept of third-party ownership to the digital age, and fortunately states that this standard shouldn’t apply to “modern-day equivalents of an individual’s own ‘papers’ or ‘effects,’ even when those papers or effects are held by a third party” such as “e-mails held by Internet service provider.” But his failure to focus on the sensitivity of information rather than a surface-level assessment of whether it constitutes 21st century “papers” could not only have devastating effects on the security of our location information, but could also have serious ramifications on an enormous and ever-increasing variety of intimate details of our lives that are stored in the cloud rather than a desk drawer.

Justice Alito ignores this elephant in the room entirely, arguing that the fact that third parties hold the data negates privacy rights without ever mentioning email, cloud computing, or the host of other clearly private digital items that would be freely available to government under his viewpoint. Justice Thomas takes a more dogmatic view, arguing that physical “property” is the only bounds of the Fourth Amendment, going so far as to oppose 50-year-old precedent established in Katz v United States that protected Americans from warrantless wiretaps.

Justice Gorsuch takes a more reasonable view of the problem, but fails to see it through to a solution. He acknowledges the idea that the government could “demand a copy of all your e-mails from Google or Microsoft without implicating your Fourth Amendment rights” is unthinkable, and criticizes the general concept that third parties holding information should be dispositive in dismissing Fourth Amendment rights. But he only goes on to offer a vague outline of factors—such as level of choice and extent of access—that should guide courts in assessing ownership and privacy rights. This may spur interesting legal theories and law review articles and be entertaining to boot (“You would not expect … the valet to lend your car to his buddy; or the neighbor [watching the dog] to put Fido up for adoption”), but they do not offer the clear answers needed now on pervasive surveillance technologies that are currently affecting millions of Americans.

Chief Justice Roberts and the majority are wiser to note that the Founders wrote the Fourth Amendment to protect the content we carry on our persons and in our papers, not the physical apparatus that held them, and for the Court to apply clear standards regarding the privacy of the information at issue. A slightly broader ruling applying those same standards to cellphone tracking as a whole could have resulted in greater clarity for law enforcement, and a stronger protection of individuals’ rights. But Carpenter will still be lauded as a critical moment in applying the Fourth Amendment to the digital age. By establishing as law that the Fourth Amendment is meant to set limits on government power to watch its citizens, that our interactions with modern technology is sometimes a necessity of life rather than a “voluntary” choice, and that there is privacy in public spaces, the Supreme Court has laid a strong foundation for protecting the right to privacy for decades to come, no matter what advances in technology and surveillance power they bring.