On Monday, the Supreme Court granted certiorari in Carpenter v. United States, a Sixth Circuit case that provides the Court with the opportunity to clarify whether individuals have a reasonable expectation of privacy in location data shared with electronic communications service providers. Specifically, the Court will consider whether the Fourth Amendment requires law enforcement to obtain a warrant for the search and seizure of wireless carriers’ cell phone data that reveals the cell phone user’s location over the course of several months; or whether such location information falls within the long-recognized “third-party doctrine” exception to Fourth Amendment protections. A definitive Supreme Court holding on these issues could clarify presently muddled case law surrounding cell-site tracking data and perhaps inform judicial interpretations of privacy torts and other issues related to the collection, use, and sharing of location data.

In the petition for certiorari, Carpenter sought review of the Sixth Circuit’s decision to uphold his conviction for a series of armed robberies throughout Ohio and Michigan. At trial, the government used cell-site tracking data from a cellular service provider to place Carpenter near the crime scenes when they occurred. The government acquired the data pursuant to a court order issued under the Stored Communications Act, 18 U.S.C. §§ 2703(c)(1)(B), (d), which permits law enforcement to compel providers of electronic communications services to disclose client records in response to court orders that are supported by “specific and articulable facts showing that there are reasonable grounds to believe” that the requested records “are relevant and material to an ongoing criminal investigation.” The “reasonable grounds” requirement for a § 2703(d) order is a significantly lower standard than the “probable cause” requirement required to obtain a warrant for Fourth Amendment searches or seizures.

A three-judge panel of the Sixth Circuit held that the government did not violate Carpenter’s Fourth Amendment rights by failing to obtain a search warrant for his cell-site tracking data. The panel focused on the third-party doctrine—under which no legitimate expectation of privacy exists in information voluntarily provided to third parties. Though the Fourth Amendment generally protects subjective and reasonable privacy expectations (in addition to protecting individuals from government trespass upon physical property), Fourth Amendment jurisprudence has established the general rule that the government need not obtain a warrant for information that individuals voluntarily share with third parties.

Judge Kethledge, writing for the majority, noted that content-based information is entitled to an expectation of privacy triggering Fourth Amendment protection; whereas non-content-based information that is used “as a means of establishing communication” lacks that protection. The majority held that because cell phone users are aware, or should be aware, that cell-site tracking data is recorded by cell phone companies as a routine means of establishing and providing communication services, cell-site tracking data is most aptly classified as non-content information that carries with it no legitimate expectation of privacy; and it therefore falls outside the realm of Fourth Amendment protection. Thus, the “reasonable grounds” requirement for a § 2703(d) order is sufficient to obtain cell-site tracking data.

The majority opinion noted the 2012 Supreme Court case United States v. Jones, in which the Supreme Court held that installing a GPS tracking device on a vehicle to track its movements constitutes a search under the Fourth Amendment. The Sixth Circuit distinguished Jones on two grounds: (1) While the location information in Jones was obtained by a GPS tracking device that law enforcement placed on petitioner’s car, the cell-site location data at issue in Carpenter was obtained by police through a third party to which Carpenter had voluntarily disclosed the information, “which can only diminish the defendants’ expectation of privacy in the information those records contain;” and (2) whereas GPS tracking devices are accurate within about 50 feet of the device’s location, the location accuracy of cell-site data varies greatly and is generally far less precise—“up to 12,500 times less accurate than the GPS data in Jones.

The question before the Court is whether the warrantless search and seizure from wireless carriers of 127 days’ worth of cell-site location data is permitted under the Fourth Amendment. The answer may turn on an assessment of when location data becomes so precise as to warrant Fourth Amendment protections, and whether users of communications services cede Fourth Amendment protections by voluntarily disclosing communications and related information to providers of communications services. The latter issue could result in there being no reasonable expectation of privacy even when precise types of location data not at issue in Carpenter, such as GPS, are disclosed to electronic communications service providers. And the answers may impact issues beyond government seizures of data. If the opinion maintains that electronic communications data voluntarily disclosed to third parties is no longer subject to a reasonable expectation of privacy under the Fourth Amendment, that could impact the interpretation of privacy torts, certain data breach claims, and other issues that rely on an assessment of whether information is subject to a reasonable expectation of privacy.

Ben Peachey, in our Washington D.C. office, contributed to this post.