Cell Phone Owners Have a Reasonable Expectation of Privacy in Their Historical Location Data

Carpenter v. United States, recently decided by the U.S. Supreme Court, is the first High Court decision to address “the ability to chronicle a person’s past movements through the record of his cell phone signals.”[i] The case arose when the federal government relied on a subpoena issued under the Stored Communications Act to obtain cell-site location information (CSLI) from Carpenter’s cell phone providers. The location data provided by the CSLI records was central to convicting Carpenter of robbery. Carpenter unsuccessfully argued both at trial and on appeal that the federal government was required to obtain a warrant under the Fourth Amendment to seize the CSLI records.

The High Court held that “an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through CSLI,”[ii] that the government’s acquisition of Carpenter’s CSLI records was a search and that “the Government must generally obtain a warrant supported by probable cause before acquiring such records.”[iii] Specifically addressing the decision’s application to third parties, the Court stated: “We hold only that a warrant is required in the rare case where the suspect has a legitimate privacy interest in records held by a third party.”[iv]

Although the Court indicated that the Carpenter decision is narrow, it is a notable decision in at least three ways:

1) it affirms that the Fourth Amendment protects privacy rights connected to people, not just privacy rights connected to property;

2) it rejects a mechanical application of the third-party doctrine; and

3) it recognizes that law enforcement now has the potential to access years of an individual’s location information that was collected before law enforcement even knew that it wanted to follow that individual.

Keep reading for more details on each of these intriguing topics.

The Fourth Amendment Protects Privacy Rights Connected to People.

Amendment IV

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.[v]

Previous Court rulings indicate that “the Founding generation crafted the Fourth Amendment as a response to the reviled ‘general warrants’ and ‘writs of assistance’ of the colonial era, which allowed British officers to rummage through homes in an unrestrained search for evidence of criminal activity.” [vi]

That sounds as if a physical trespass is required. However, the Court recognized in 1967 that “the Fourth Amendment protects people, not places.”[vii] In 1992, the Court recognized that “property rights are not the sole measure of Fourth Amendment violations.”[viii] In general, when an individual seeks to preserve a private sphere and society recognizes that expectation of privacy as reasonable, government intrusion into that private sphere usually qualifies as a search, requiring a warrant supported by probable cause.

As technology advances, so does the government’s ability to encroach into private spheres with surveillance tools. Two guideposts the Court follows in applying the Fourth Amendment to cases involving advancing technology are 1) that the Fourth Amendment aspires to protect the privacies of life from arbitrary power and 2) that the Fourth Amendment’s Framers sought to create barriers to a too permeating police surveillance.

Reject Mechanical Application of the Third-Party Doctrine!

The third-party doctrine asserts that an individual has no legitimate expectation of privacy in information that individual voluntarily turns over to third parties. For example, the government can lawfully obtain records from a suspect’s bank with a subpoena instead of a warrant. The rationale is that the individual assumes the risk that the third party will provide the information to the government. The government can usually obtain information from third party recipients without activating Fourth Amendment protections.

The Court determined that cell-site records are a qualitatively different category of records from bank records. Cell-site records contain a detailed and comprehensive record of a person’s movements. The Court refused to apply the third-party doctrine to the cell-site records generated by Carpenter’s phone.

Given the unique nature of cellphone location records, the fact that the information is held by a third party does not by itself overcome the user’s claim to Fourth Amendment protection. Whether the Government employs its own surveillance technology as in Jones[ix] or leverages the technology of a wireless carrier, we hold that an individual maintains a legitimate expectation of privacy in the record of his physical movements as captured through CSLI. The location information obtained from Carpenter’s wireless carriers was the product of a search.[x]

The Court determined that cell site records are not mere business records, but result from “the seismic shifts in digital technology that made possible the tracking of not only Carpenter’s location but also everyone else’s, not for a short period but for years and years.”[xi]

According to the Court, applying the third-party doctrine to this case would be a significant extension of the doctrine to a distinct category of information. The third-party doctrine results from a knowing sharing of information with third parties, leading to a reduced expectation of privacy in the information shared. Cell phone location information is not true sharing by the cell phone user and is created by simply turning on the phone.

In light of the deeply revealing nature of CSLI, its depth, breadth, and comprehensive reach, and the inescapable and automatic nature of its collection, the fact that such information is gathered by a third party does not make it any less deserving of Fourth Amendment protection. The Government’s acquisition of the cell-site records here was a search under that Amendment.[xii]

This case represents a smack down on automatically applying the third-party doctrine.

Law Enforcement Now has the Potential to Access Years of Past Location Data on You Collected Even Before They Decided They Should Watch You.

Historically, society has expected that law enforcement agents would not and could not secretly monitor and catalogue every single movement of an individual’s car over a long period, let alone monitor an individual person in such a manner. That expectation is transgressed if the government is allowed access to cell-site records.

Mapping a cell phone’s location over the course of 127 days provides an all-encompassing record of the holder’s whereabouts. As with GPS information, the time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them his familial, political, professional, religious, and sexual associations. These location records hold for many Americans the ‘privacies of life.’ And like GPS monitoring, cell phone tracking is remarkably easy, cheap, and efficient compared to traditional investigative tools. With just the click of a button, the Government can access each carrier’s deep repository of historical location information at practically no expense.[xiii]

The Court noted that historical cell-site record tracking is even more invasive than tracking a person’s car. People leave their cars, but carry their cell phones with them everywhere.

A new concern involves the retrospective quality of historical cell phone data. Law enforcement now has access to information that was previously unknowable.

In the past, attempts to reconstruct a person’s movements were limited by a dearth of records and the frailties of recollection. With access to CSLI, the Government can now travel back in time to retrace a person’s whereabouts, subject only to the retention polices of the wireless carriers, which currently maintain records for up to five years. Critically, because location information is continually logged for all of the 400 million devices in the United States—not just those belonging to persons who might happen to come under investigation—this newfound tracking capacity runs against everyone. Unlike with the GPS device in Jones, police need not even know in advance whether they want to follow a particular individual, or when.

Whoever the suspect turns out to be, he has effectively been tailed every moment of every day for five years, and the police may—in the Government’s view—call upon the results of that surveillance without regard to the constraints of the Fourth Amendment. Only the few without cell phones could escape this tireless and absolute surveillance.[xiv]

The Court noted that the current state of technology allows wireless carriers to pinpoint a phone’s location within 50 meters. The Court ruled that the government invaded Carpenter’s reasonable expectation of privacy in the whole of his physical movements when it accessed CSLI from the wireless carriers.

The Court Did Not Discuss Data Ownership.

The Court did not decide or even discuss who owns the CSLI data. The Court did not determine the full parameters of the cell phone owner’s privacy interest in her location data. The question of whether a privacy interest equates to data ownership was not addressed. Maybe that is a question that does not need to be answered. For now, it may be enough to recognize that individuals can have a legitimate privacy interest in information about them held by and even collected by others.

[i] Carpenter v. United States, No. 16-402, slip op. at 10, 585 U.S. ____ (2018). https://www.supremecourt.gov/opinions/17pdf/16-402_h315.pdf

[ii] Id., slip op. at 11.

[iii] Id., slip op. at 18.

[iv] Id., slip op. at 21.

[v] U.S. Const. amend. IV. https://www.law.cornell.edu/constitution/fourth_amendment

[vi] See id., slip op. at 4-5.

[vii] Id., slip op. at 5.

[viii] Id., slip op. at 5.

[ix] United States v. Jones, 565 U. S. 400, 411 (2012). FBI agents’ installing a GPS tracking device on Jones’s vehicle without a warrant and remotely monitoring the vehicle’s movements for 28 days held to violate the Fourth Amendment.

[x] See id., slip op. at 11.

[xi] Id., slip op. at 15.

[xii] Id., slip op. at 22.

[xiii] Id., slip op. at 12-13.

[xiv] Id., slip op. at 13-14.