In the next few weeks, the Supreme Court will be deciding Carpenter v. United States, a major privacy case examining whether the government needs a warrant to find out where your cell phone has been.
In 2011, the government investigated Timothy Carpenter for involvement in a string of robberies. To learn if he had been near the robbery locations, law enforcement officials asked his cell phone company for 127 days’ worth of his cell site location information (CSLI). To get this information — recorded by the phone company every time someone makes a call, sends a text message, or receives data on their cell phone — the government used a court order. It did not use a warrant, which is required by the Fourth Amendment when the government conducts a “search.”
The Supreme Court agreed to hear the case to decide whether the warrantless seizure of records “revealing the location and movements of a cell phone user over the course of 127 days” is allowed by the Fourth Amendment. The case involves the privacy implications of our rapidly evolving use of technology in the digital age — and the need for our laws to evolve in tandem.
Here’s what you need to know:
1. What level of privacy should cell phone users expect?
Since a warrant is required when the government conducts a “search,” Mr. Carpenter argued that the government violated the Fourth Amendment by obtaining his data without a warrant. The trial court and appeals court disagreed, relying on a 1967 Supreme Court case finding that the Fourth Amendment kicks in when an individual has a “reasonable expectation of privacy” in the information he is trying to protect, the appeals court reasoned that because the location data didn’t reveal the content of his conversations, Mr. Carpenter did not have a “reasonable expectation” that the company would keep it private.
The court also pointed to a decades-old rule called the “third-party doctrine,” which holds that the government generally doesn’t need a warrant to get information about an individual from a company or another third party with whom she has “voluntarily” shared it. Reasoning that cell phone users know their providers determine their location to do things like connect calls, the court concluded that users have no reasonable expectation of privacy in their location data.
2. Why does it matter if the police can get your cell site location information?
The ubiquity and sophistication of modern cell phones, and the proliferation of cell phone towers, has led to a substantial increase in the availability and accuracy of cell site location information. Service providers store location data for up to seven years. This information can reveal a great deal about where someone lives, whom they visit, where they spend their off hours, and more, with significant implications for freedom of speech and association. In a related case, armed with 220 days of CSLI, the American Civil Liberties Union was able to determine when the defendant was at the OB/GYN with his pregnant wife, when he arrived home, and even when he slept away from his house one night. This sensitive data deserves the highest level of protection the Constitution offers.
3. What is the third-party doctrine, and why does it matter?
The third-party doctrine says that when an individual shares information or records with a business or even another person, she relinquishes any reasonable expectation that her information will remain private. In the 1970s, the Supreme Court found that there was no Fourth Amendment protection for checks given to a bank or phone numbers dialed and transmitted to a phone company. The reasoning of these cases has been extended to digital records by the government as well as some lower courts.
However, as Justice Sonia Sotomayor wrote in her concurrence in a case involving GPS tracking, “[t]his approach is ill-suited to the digital age, in which people reveal a great deal of information about themselves to third parties in the course of carrying out mundane tasks.” We now share a great deal of information with third parties — email, personal pictures, health records, and more — by using cell phones, other smart devices, and the cloud, but few of us would say we’ve agreed to let the government rummage through all that personal data.
That’s why the Brennan Center urged the Supreme Court to limit the third-party doctrine when it comes to CSLI to ensure that, in the earlier words of the Supreme Court, the “power of technology” does not “shrink the realm of guaranteed privacy.”
4. Do we know what the Court will decide?
There have long been signs that many of the Supreme Court’s justices are rethinking whether or how the third-party doctrine should apply to sensitive digital data. At oral argument, it appeared that a majority of Justices thought the warrantless collection of CSLI violated the Fourth Amendment. There seemed to be little consensus, however, on how the Court should get there.
Some of the justices cited the staggering power of modern-day surveillance technologies, with capabilities that would have been inconceivable to the Founders. In Justice Breyer’s words, “the village snoop had a fallible memory and didn’t follow people for 127 days.” Some justices thought it would be reasonable simply to carve out an exception from the third-party doctrine for cell phone location information. Chief Justice John Roberts drew on a recent decision to suggest that having a cell phone is not a choice but a necessity, so that disclosure of cell phone data to a company could not be truly “voluntary.” And Justice Neil Gorsuch suggested users might have a Fourth Amendment property right to their cell phone data.
With the justices taking such different tacks, the Court could end up resolving the case in any number of ways: It could abolish the third-party doctrine entirely; it could decide cell phone data is sensitive enough that it should be exempt from the doctrine; it could determine a minimum number of days of location tracking that would trigger a warrant requirement; or it could look to property rights.
5. Will this decision mean that the law has finally caught up with technology?
Not necessarily. Technology has significantly changed since the Carpenter investigation in 2011. At the time, the police were able to use CSLI to isolate Mr. Carpenter’s position to within about half a mile to two miles from the cell tower to which his phone connected, which was useful enough to serve as evidence in his prosecution but not as accurate as a GPS tracker.
In 2018, the landscape looks very different. Given the huge increase in the number and concentration of cell towers since 2011, as well as the development of “small cell” technology, in some circumstances police could pinpoint someone’s location to a particular floor in a building or even to a particular apartment.
In light of these developments, a decision from the Supreme Court relying on the particular facts of this case is likely to be obsolete almost immediately. The Supreme Court could choose to craft an opinion with a longer legacy, however. It could tackle location information as a whole, beyond the specific facts of this case, or it could even take on the third-party doctrine itself. Whatever the Supreme Court decides, it is sure to have long-term consequences for the privacy of the average cell phone user.