US Supreme Court: Warrant Required for Search of Cell-Site Records

Carpenter v United States, 585 US ___ (2018) (delivered June 22, 2018)
The Supreme Court has held that accessing cell-site records is a Fourth Amendment search requiring a warrant supported by probable cause in Carpenter v United States, a 5-4 decision authored by Chief Justice Roberts. Each time a cell phone connects with a cell-site (such as a cell tower), a time-stamped record is created, known as cell-site location information (CSLI). CSLI provides a “comprehensive chronicle” of a user’s past movements. The Court held that Carpenter had a reasonable expectation of privacy in “the whole of his physical movements” as captured in CSLI. Carpenter’s expectation of privacy was not reduced when he “shared” his cell-site information with his providers because cell phones are essential and Carpenter made no affirmative act to log the CLSI. The government violated the Fourth Amendment when it searched Carpenter’s cell-site records without a warrant.

Timothy Carpenter was convicted on charges arising from a string of robberies at Radio Shack and T-Mobile stores in Michigan and Ohio. After a suspect identified Carpenter as an accomplice, the prosecution requested (and a federal magistrate issued) an order to obtain Carpenter’s cell phone records under the Stored Information Act, which permits the Government to compel such records when there are articulable facts that show reasonable grounds to believe that the records are material to an ongoing investigation. Pursuant to the order, the government obtained records containing 12,898 location points “cataloging” Carpenter’s movements for a period of 129 days. These records placed Carpenter at the location of four robberies at the time of the robberies.

Carpenter moved for suppression in the federal district court arguing that the government’s seizure of the cell-site records without a warrant violated the Fourth Amendment. The district court denied the motion, and the Court of Appeals for the Sixth Circuit affirmed, holding that Carpenter did not have a reasonable expectation of privacy in the location information because he had shared it with his wireless carriers.

The Supreme Court overruled the Sixth Circuit, holding that the warrantless seizure of Carpenter’s cell-site records violated the Fourth Amendment. The Fourth Amendment protects people, not places, the Court stated, citing Katz v United States, 389 US 347 (1967). Accordingly, when a person has a certain expectation of privacy that society is willing to accept as reasonable, intrusion into that “private sphere” is generally a search and requires a warrant supported by probable cause.

Carpenter had a reasonable expectation of privacy in his cell-site records, the Court determined, because individuals have a reasonable expectation of privacy in “the whole of their physical movements.” A cell phone is almost a “feature of anatomy” that tracks nearly exactly the movements of its user. And it follows its user beyond public streets and places into private residences, doctor’s offices, and many other potentially revealing locations.

Carpenter’s expectation of privacy in his cell-site records is also one that society is willing to accept as reasonable because a search of those records goes far beyond surveillance as normally understood. Prior to the digital age, the Court observed, pursuing a suspect for an extended period was difficult, costly, and rarely undertaken. Accordingly, society’s expectation has been that law enforcement would not, or could not, catalogue an individual’s every single movement for very long.

A warrantless search of cell-site records contravenes that expectation, the Court determined. Cell phone tracking is easy, cheap, and efficient compared to traditional investigative tools. CSLI allows the government to retrace a person’s whereabouts in detail, information that was previously unknowable. And this data is continually collected from every cell phone, not just those belonging to persons who might come under suspicion, and retained for up to five years. With access to CSLI, police need not know whether they want to follow a particular person, or when. Whoever turns out to be the suspect has been effectively trailed every moment of every day for up to five years. Such absolute surveillance is contrary to Katz and to the foundational purposes of the Fourth Amendment.

The Court also determined that the third-party doctrine did not apply. Under the third-party doctrine, an individual does not have a reasonable expectation of privacy in information the individual has shared with a third-party. The Court had previously applied that doctrine to validate warrantless searches of bank records and short-term telephone call records.

The Government argued that the doctrine applied because the cell-site records are business records, and they were acquired by request to a third-party. But the Court found that the argument failed to recognize the “seismic shifts in digital technology” that make it possible to track not only Carpenter’s location but also everyone else’s and not for a short period but for years. Unlike the “nosy neighbor,” the Court reasoned, wireless providers are “ever alert” with nearly infallible memory. Cell-site records provide a detailed chronicle of a person’s presence compiled over years and, thus, implicate privacy concerns far beyond those to which the third-party doctrine has previously been applied.

Further, the Court concluded, cell-site records are not “shared” as the term is normally understood. Cell phones are indispensable to participation in modern society; cell-site records are logged without any affirmative act of the user; and any activity on the phone generates CSLI. Due to the “deeply revealing nature of CSLI” and its comprehensive and inescapable nature, the Court declined to extend the third-party doctrine to cell-site records. The government’s acquisition of Carpenter’s cell-site records was a warrantless search in violation of the Fourth Amendment.

The Court stated that its decision is a narrow one. The decision does not disturb conventional surveillance techniques, such as security cameras or access to business records that might incidentally reveal location information. And the decision does not preclude a warrantless search of CSLI if an exception to the warrant requirement, such as exigent circumstances, exists.

Justice Kennedy dissented, joined by Justices Thomas and Alito. He would have held that the government did not search anything of Carpenter’s when it obtained cell-site records from wireless providers that create and keep them.

Justice Thomas dissented. He would also have held that the government did not search anything of Carpenter’s when it obtained cell-site records from wireless providers. Further, he would conclude that the Katz test has no place in the text or history of the Fourth Amendment, which focuses on property, not persons.   

Justice Alito dissented, joined by Justice Thomas. He would have held that an order requiring a party to produce records is not a search; a search takes place only when officers are dispatched to enter private premises to search through private papers or effects. The Justice further predicted that the majority opinion will guarantee a “blizzard of litigation.”

Justice Gorsuch dissented. He called upon the Court to return to a traditional understanding of the Fourth Amendment, which focused on houses, papers, and effects. While Katz may still have some place in traditional analysis, he opined, it should not hold primacy in Fourth Amendment law.

Congratulations to the Michigan lawyers who worked on this case, including Mr. Carpenter’s counsel, Harold Guerwitz, and his associate Jason Eggert, who is now an Assistant Defender at SADO, and to our friends at the ACLU of Michigan.

Read the opinion here.