The Supreme Court recognizes privacy right to cell phone location history.

On May 22, 2018, the U.S. Supreme Court issued an important decision extending the Fourth Amendment right against unlawful search and seizure into the digital age. In Thomas Ivory Carpenter v. United States, the Court sided with the privacy rights of cellphone users over law enforcement using private tracking data compiled and saved by cell phone companies. At issue was whether the Fourth Amendment required law enforcement to obtain a warrant before accessing cell phone location history from cell phone service providers.

The Supreme Court recognized the importance and prominence of cell phones in an individual’s daily life and the right to privacy of the sensitive information generated by the cell phone’s use.

The Court stated that there are 396 million cell phone service accounts in the United States for a Nation of 326 million people. Cell phones perform their wide and growing variety of functions by connecting to a set of radio antennas called “cell sites” mounted on towers, light posts, flagpoles, church steeples, or the sides of buildings. Cell sites typically have several directional antennas that divide the covered area into sectors. Cell phones continuously scan their environment looking for the best signal, which generally comes from the closest cell site. Cell phones, smartphones, tablets, and other devices tap into the wireless network several times a minute whenever their signal is on. Each time the smart device connects to a cell site, it generates a time-stamped record known as cell-site location information (CSLI). Wireless carriers collect and store CSLI for their own business purposes, including finding weak spots in their network and applying “roaming” charges when another carrier routes data through their cell sites. In addition, wireless carriers often sell aggregated location records to data brokers, without individual identifying information. Carriers retained CSLI for the start and end of incoming calls,text messages and routine data connections. Accordingly, modern cell phones generate increasingly vast amounts of increasingly precise CSLI.

In December of 2010, there were a series of robberies in Michigan and Ohio of cell phones, ironically. Several cell phones stores were robbed of their cell phones at gunpoint. Eventually, the FBI arrested four men suspected of the robberies. One of the men confessed and provided names and cell phone numbers of accomplices including the petitioner, Timothy Carpenter.

Prosecutors applied for court orders under the Stored Communications Act (“SCA”) to obtain cell phone records for Carpenter and several other suspects. The SCA permits the Government to compel the disclosure of certain telecommunications records when it “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.” The SCA stops short of requiring that prosecutors demonstrate probable cause, which is necessary to obtain a warrant.

Federal Magistrate Judges issued two orders directing Carpenter’s wireless carriers to disclose the CSLI for Carpenter’s telephone at call origination and at call termination for incoming and outgoing calls during the four-month period when the string of robberies occurred.

Law enforcement was able to track Carpenter’s locations and connect Carpenter to the crimes by obtaining more than 100 days’ worth of his smartphone location data records without a warrant. The location data records placed his phone in over 12,000 locations including when he was at church and whether or not he spent the night at home.

Before his trial, Carpenter argued that obtaining the records constituted a Fourth Amendment search, and therefore the police should have needed a warrant. His motion was denied, and the Sixth Circuit Court of Appeals later upheld the case.

The Supreme Court reversed and remanded with Chief Justice Roberts providing the deciding vote and writing the majority opinion.

The Court held that the acquisition of Carpenter’s CSLI records was a Fourth Amendment search. The Fourth Amendment protects not only property interests but certain expectations of privacy as well. Thus, when an individual “seeks to preserve some thing as private,” and his expectation of privacy is “one that society is prepared to recognize as reasonable,” official intrusion into that sphere generally qualifies as a search and requires a warrant supported by probable cause.

The Court further held that the digital data at issue, personal location information maintained by a third party, does not fit neatly under existing precedents but lies at the intersection of two lines of cases. One set of cases addressing a person’s expectation of privacy in his physical location and movements. The other set of cases addresses a person’s expectation of privacy in information voluntarily turned over to third parties.

The third-party doctrine, as first set forth in United States v. Miller, 425 U. S. 435 (no expectation of privacy in financial records held by a bank), and Smith v. Maryland, 442 U. S. 735 (no expectation of privacy in records of dialed telephone numbers conveyed to telephone company) holds that information customers voluntarily provide to a third party is outside the bounds of Fourth Amendment protections and, therefore, law enforcement does not need a warrant in order to access that information.

The Supreme Court stated that the third-party doctrine partly does not apply given “the nature of the particular documents sought” and “legitimate ‘expectation of privacy’ concerning their contents.” The Supreme Court cited prior case law where the court had already recognized that individuals have a reasonable expectation of privacy in the whole of their physical movements. Additionally, the Supreme Court recognized in many way CSLI is not voluntarily provided by the cell phone users but automatically obtained when the cell phone is used in some form.

The Supreme Court found the Government did not obtain a warrant supported by probable cause before acquiring Carpenter’s cell-site records. It acquired those records pursuant to a court order under the SCA, which required the Government to show “reasonable grounds” for believing that the records were “relevant and material to an ongoing investigation” which falls well short of the probable cause required for a warrant.