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The Unwarranted Collection of Cell Phone Data?

On Behalf of | Jul 17, 2018 | Cybersecurity & Data Privacy

Carpenter v. United States, ___ U.S. ___, No. 16-402 (22 June 2018)

Maybe in his mind Timothy Carpenter saw himself as a local boy trying to get ahead, but others saw him for what he really was, an armed robber who, with other bandits, robbed nine stores in Michigan and Ohio.  In due course, the police arrested four suspects, and, there being no honor among thieves, one of the suspects confessed, identified Carpenter as the ringleader and told the police Carpenter’s cell phone number.

The prosecutors applied for court orders under the Stored Communications Act (SCA) to obtain the cell phone records for Carpenter’s cell phone.  The SCA permits the government to apply for a court order to compel the disclosure of certain telecommunications records, if the government “offers specific and articulable facts showing that there are reasonable grounds to believe” that the records sought “are relevant and material to an ongoing criminal investigation.” 18 U.S.C. §2703(d).  The SCA’s standard for a court order is not as demanding as the probable cause standard for issuance of a search warrant under the 4th Amendment.

A federal magistrate judge issued two orders directing Carpenter’s wireless carriers – MetroPCS and Sprint – to disclose cell site location information (CSLI) for Carpenter’s phone.  Pursuant to the orders, MetroPCS and Sprint produced a total of 129 days of phone records.

Unless turned off and placed in “airplane mode,” a cell phone continuously scans the environment looking for the best signal, which usually comes from the nearest cell site, typically (but not always) a cell tower.  Each time a cell phone connects to a cell site, it generates a time-stamped record known as CSLI.  Wireless carriers collect and store CSLI, and some carriers store the information for as long as five years.  CSLI provides a comprehensive record of a cell phone’s location at specific times over a long period of time.  The CSLI for Carpenter’s phone showed that his cell phone was in the vicinity of several of the armed robberies at the time of the robberies.

Carpenter moved to suppress the CSLI evidence, contending that the government had obtained the evidence without a warrant supported by probable cause.  The district court denied the motion and the 6th Circuit affirmed, holding that the CSLI on Carpenter’s phone was not protected by the 4th Amendment.  The 6th Circuit said that, under the so-called third-party doctrine, the CSLI records belonged to the carrier, not to Carpenter.  Therefore, the government did not search Carpenter’s person, houses, papers or effects, and the 4th Amendment did not require a warrant.  The Supreme Court reversed.  The Court rejected application of the third-party doctrine to CSLI and held “that an individual maintains a legitimate expectation of privacy in the records of his physical movements as captured through CSLI.”

The 4th Amendment says that “[t]he right of the people to be secure in their persons, houses, papers and effects, against unreasonable searches and seizures, shall not be infringed, and no Warrants shall issue, but upon probable cause…”  In the instant case, the police did not directly search Carpenter’s person, houses, papers or effects; the police searched the carriers’ records of Carpenter’s movement.  The carriers created and stored the CSLI, and the CSLI belonged to the carriers.  Carpenter had no property interest in the CSLI.

By connecting the 4th Amendment to the right to be secure in one’s person, houses, papers and effects, the text of the 4th Amendment reflects its close connection to rights in property.  United States v. Jones, 565 U.S. 400, 405 (2012).  By using his cell phone, Carpenter voluntarily shared his location and movements with the cell phone carrier, and the Court has drawn a line between what a person keeps to himself and what he shares with others.  See United States v. Miller, 425 U.S. 435, 443 (1976).  How, then, did the Court reach the conclusion that the government’s acquisition of Carpenter’s CSLI without a warrant violated the 4th Amendment?

For much of history, 4th Amendment search doctrine was tied to common law trespass.  If the search was a common law trespass, then the 4th Amendment required the government to have a search warrant.  In 1967, the Supreme Court broadened the 4th Amendment to apply to areas in which a person has a “legitimate expectation of privacy,” even if the person does not have a property interest in the area searched, and there was no trespass in the traditional common law sense of a trespass.  The Court wrote that “the 4th Amendment protects people, not places,” and “what [a person] seeks to preserve as private . . . may be constitutionally protected.” Katz v. United States, 389 U.S. 347, 353-361 (1967).  Katz was a case in which the police, without a warrant, attached a listening device to a phone booth.[1]

In Katz the Court said that if a person seeks to preserve something as private, and if her expectation of privacy is an expectation that society recognizes as reasonable, then official government intrusion into that private sphere generally qualifies as a search under the 4th Amendment; and the government must have a warrant to conduct the search.  Later, in Jones, supra, 565 U.S. at 430, the Court said that individuals have a reasonable expectation of privacy “in the whole of their physical movements.” Jones, 565 U.S. at 430.  In Jones, the police attached a GPS tracking device to a suspect’s car and tracked his movements for 28 days.

Cell sites scoop up huge amounts of information on a person’s movements over time.  CSLI is comprehensive and tracks nearly exactly the movements of the owner of the cell phone.  It is like an ankle monitor providing a detailed chronicle of a person’s physical presence compiled every day, every movement, over several years.  CSLI is a record of the “whole of [a person’s] physical movements.”  Although the Court did not explicitly say it, there is a suggestion in the opinion that when the government searches this enormous mound of undifferentiated CSLI data without a warrant, it is equivalent to executing a general warrant, which the 4th Amendment aims at preventing.

In this case, the Court declined to apply the traditional trespass theory of 4th Amendment searches and rejected the third-party doctrine which is an adjunct to the trespass theory.  What guideposts did the Court use to conclude that a search of CSLI requires a warrant?  The Court said that the basic purposes of the 4th Amendment are to protect privacy against “arbitrary power,” Boyd v. United States, 116 U.S. 616, 630 (1886) and to “place obstacles in the way of permeating police surveillance.”  See United States v. Di Re, 332 U.S. 581, 595 (1948).  These statements by the Court put primary emphasis on limiting the reach of the modern surveillance state, the “deep state,” the Orwellian “Big Brother” state.  The Court said that the government’s position in the litigation “fails to contend with the seismic shifts in digital technology that made possible the tracking of not only Carpenter’s location but everyone else’s, not for a short time but for years and years.” (Slip op. at p. 15)  “CSLI is an entirely different species of record – something that implicates basic Fourth Amendment concerns about arbitrary government power much more directly than corporate tax or payroll records,” for example. (Slip op. at p. 20)

The Court made a large point that 4th Amendment “analysis is informed by historical understanding of what was deemed an unreasonable search and seizure when [the Fourth Amendment] was adopted.”  Carroll v. United States, 267 U.S. 132, 149 (1925).  Courts must heed the founders understanding of privacy “. . . to assure preservation of that degree of privacy against the government that existed when the 4th Amendment was adopted.” Kyllo v. United States, 533 U.S. 27, 34 (2001).  Thus, the government cannot use new technology permitting enhanced surveillance to circumvent the 4th Amendment’s warrant requirement.

In addition to Carpenter’s specific holding concerning CSLI, I think that the opinion can be read as endorsing several general propositions.

  1. If new technology exceeds the reasonably possible surveillance and search available to the government when the 4th Amendment was adopted, then the government must get a warrant.
  2. If a device or system holds vast, comprehensive information about a person, then the traditional rationales allowing warrantless search have diminished force, and the police should search only with a warrant.
  3. If a mode of surveillance or data collection was not practical before the digital age, then in the digital age a search is permissible only with a warrant.
  4. A person has a legitimate expectation of privacy in the “whole” of his physical movements, meaning his movements over an extended period of time, although the opinion does not specify what is an extended period of time.

Justices Kennedy, Thomas, Alito and Gorsuch dissented, all for different reasons, but there is one unifying thread appearing in the dissents.  The legislatures, not the courts, should define what society considers to be a legitimate expectation of privacy.

[1] For readers under the age 30 who have never known a world without cellphones, I offer this bit of enlightenment.  In ancient times, people had telephones in their homes that transmitted over landlines.  A person outside her home and away from her landline phone could only make a phone call from a public pay phone, many of which, but not all, were located in phone booths.  Life was hard back then but somehow we survived.

John Polk is a Special Counsel at Berenzweig Leonard, LLP. John can be reached at [email protected].