Supreme Court Rules that Obtaining Cell Site Location Information Is a Search

On Friday, the Supreme Court issued a long-awaited opinion in Carpenter v. United States. The Court held that when law enforcement obtains long-term cell site location information from a suspect’s service provider, it conducts a Fourth Amendment search that normally requires a warrant. Although the majority opinion states that it “is a narrow one,” the dissenting Justices and some scholars see it as a seismic shift that may have many aftershocks. I’ll summarize the case and then use former Secretary of Defense Donald Rumsfeld’s famous approach to address the “known knowns,” the “known unknowns,” and the “unknown unknowns” after Carpenter.

Facts. Carpenter was suspected of participating in a series of store robberies in Michigan and Ohio. The FBI sought and obtained two court orders requiring Carpenter’s cell phone service providers to produce records about Carpenter’s account, including cell site location information. One order covered 152 days, though for reasons not given in the opinion, the service provider only produced records for 127 days. The second order covered seven days, but the service provider only produced records for two days. The cell site location information put Carpenter in the vicinity of several robberies and became important evidence against him.

Procedural history. Carpenter moved to suppress the records, arguing that he had a reasonable expectation of privacy in the records and in the location information that they revealed; that the FBI had therefore engaged in a search, for Fourth Amendment purposes, when agents obtained the records; and that the agents had acted without a warrant or an exception to the warrant requirement and so had violated the Fourth Amendment. It is important to note that the agents had obtained the orders under 18 U.S.C. § 2703(d), which allows investigators to get a court order for telecommunication records when they can provide “specific and articulable facts showing that there are reasonable grounds to believe that the . . . records or other information sought[] are relevant and material to an ongoing criminal investigation.” The “specific and articulable facts” standard is something like reasonable suspicion, so it’s less than probable cause and the orders weren’t the functional equivalent of a warrant.

The trial court denied Carpenter’s motion. He went to trial, was convicted, was sentenced to over 100 years in prison, and appealed. The Sixth Circuit affirmed, ruling that Carpenter had no reasonable expectation of privacy in the cell site location information because he had shared that information with the service providers in the course of using his phone. In other words, the third party doctrine applied to cell site location information just as the Supreme Court has ruled that it applies to bank records, see United States v. Miller, 425 U.S. 435 (1976), and pen register information, see Smith v. Maryland, 442 U.S. 735 (1979). Several other federal courts of appeals had decided similar cases in similar ways. Carpenter sought and obtained Supreme Court review.

Majority opinion. Chief Justice Roberts wrote the majority opinion reversing the Sixth Circuit, joined by Justices Breyer, Ginsburg, Sotomayor, and Kagan. He wrote that “requests for cell-site records lie at the intersection of two lines of cases.” One set of cases concern the third party doctrine — as noted above, the idea that when a person voluntarily shares information with a third party, the person loses any reasonable expectation of privacy in the information. The other set of cases concern “a person’s expectation of privacy in his physical location and movements.” Of particular significance on this front was was United States v. Jones, 565 U.S. 400 (2012), a GPS tracking case in which five Justices expressed concern that long-term electronic location tracking might intrude upon the subject’s reasonable expectation of privacy. (The Court actually decided that case on the basis that installing the tracking device on a suspect’s vehicle was a search, and the Court as a whole didn’t reach the expectation of privacy issue.)

Viewing the issue through the above-described lens, the majority determined that the third-party doctrine isn’t absolute and that law enforcement access to cell site location information is such a severe threat to privacy that the third-party doctrine shouldn’t be extended to cover it. The Court noted that such information offers “an all-encompassing record of the holder’s whereabouts” and “provides an intimate window into a person’s life.” Therefore, the Court reasoned:

Given the unique nature of cell phone 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 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.

Because accessing CSLI is a search, the majority concluded, law enforcement needs a warrant, or an exception to the warrant requirement, to collect it. The FBI didn’t have one, so it violated the Fourth Amendment. The Court remanded the case to the Sixth Circuit, presumably to consider questions like whether suppression is an appropriate remedy given that the officers acted in conformity with then-existing case law and the pertinent federal statute.

Dissents. The four dissenting Justices each produced a dissent. Justice Kennedy focused mainly on the third-party doctrine, arguing that the records were the providers’ business records and that Carpenter therefore had no expectation of privacy in them. Justice Thomas argued that the entire “reasonable expectation of privacy” framework from Katz v. United States, 389 U.S. 347 (1967), is inconsistent with the text and original meaning of the Fourth Amendment. In his view, the proper analysis would focus on whether officers invaded any property interest in Carpenter’s “papers” or “effects,” which he thought plain that they did not. Justice Alito, among other points, contended that obtaining documents using compulsory process — namely, a court order requiring the service provider to produce certain records — rather than by officers’ own rummaging and inspection is not a “search.” Justice Gorsuch wrote a rather informal and conversational opinion, generally endorsing the idea that the Fourth Amendment requires a property-based, not privacy-based, analysis. Together, the opinions cover 119 pages and made for an interesting weekend of reading.

Known knowns. A few impacts of the Court’s decision are plain.

• Obtaining long term, historical CSLI is a search and requires a warrant unless an exception to the warrant requirement, such as exigent circumstances, exists. This effectively reverses State v. Perry, 243 N.C.App. 156 (2015).
• Obtaining financial records and pen register information from third party institutions like banks and service providers remains covered by the third-party doctrine and is not a search. The majority is clear that the third-party doctrine survives, and that Smith and Miller continue to govern, at a bare minimum, the types of information at issue in each of those cases.

Known unknowns. Carpenter also leaves some obvious question marks:

• What about short-term historical CSLI? Footnote three of the majority opinion observes that the Court “need not decide whether there is a limited period for which the Government may obtain an individual’s historical CSLI free from Fourth Amendment scrutiny, and if so, how long that period might be. It is sufficient for our purposes today to hold that accessing seven days of CSLI constitutes a Fourth Amendment search.” Future cases involving shorter time periods may present the issue that the Court sidestepped.
• What about real-time CSLI? The majority likewise expressly declined to offer any opinion about whether the real-time collection of CSLI constitutes a search.
• Finally, what about “tower dumps”? Again, the majority refused to express a view regarding this technique, which provides a snapshot of all the cell phones that connected to a given tower within a specific window of time, usually the time that a particular crime took place.

A cautious officer seeking any of these sorts of information may wish to do so using a warrant or the functional equivalent, such as a court order based on full probable cause. Indeed, my impression is that most agencies in North Carolina are already following this practice. Similarly, a defendant in any case involving information of this kind may wish to assert a Fourth Amendment claim if the information was obtained under a lower standard than probable cause.

Unknown unknowns. Carpenter laid bare some very deep disagreements about the Fourth Amendment, including the extent to which it was intended to protects privacy as opposed to property, and the extent to which Katz and the third-party doctrine are correct interpretations. It was a 5-4 decision and a single retirement, or change of heart, could change the entire direction of the Court. But even if the Court marches off along the path set by Carpenter, it seems likely that it will reach some unexpected destinations. The dissenting Justices certainly think that it will. For example, Justice Kennedy accused the majority of drawing an “unprincipled and unworkable line” between categories of third-party records that will “cause confusion” in application:

[T]he Court’s holding is premised on cell-site records being a “distinct category of information” from other business records. But the Court does not explain what makes something a distinct category of information. Whether credit card records are distinct from bank records; whether payment records from digital wallet applications are distinct from either; whether the electronic bank records available today are distinct from the paper and microfilm records at issue in Miller; or whether cell-phone call records are distinct from the home-phone call records at issue in Smith, are just a few of the difficult questions that require answers.

Indeed, in the age of big data, third parties collect and maintain vast troves of information about individuals and I am certain that future cases will test the logic and implications of Carpenter in contexts that I haven’t even begun to imagine. But just to illustrate the potential range of issues that might be raised, I will note that I can readily imagine questions about the following:

• Records of an individual’s search and browsing histories and social media interactions. These arguably constitute something akin to an individual’s online “location” and they have the potential to reveal a great deal of personal information.
• Medical and genetic records pertaining to an individual. Sometimes these will be protected by the physician-patient privilege, but not always — Justice Gorsuch’s opinion offers the example of a person’s DNA profile on 23andme.
• Photographs and videos stored on third-party servers. These files often reveal private moments, and may contain metadata indicating the time and location at which they were captured. Thus, a sufficiently extensive photo stream may allow investigators to, in the words of Chief Justice Roberts, “retrospective[ly] . . . access . . . a category of information otherwise unknowable” and “travel back in time to retrace a person’s whereabouts” and even activities.
• Data collected through license plate readers, pole-mounted cameras, persistent aerial surveillance, and similar techniques. Although the majority notes that it does not “call into question conventional surveillance techniques and tools, such as security cameras,” future litigants are likely to call those techniques into question. And while the short-term use of a single tool may not intrude on a reasonable expectation of privacy, perhaps a tipping point can be reached beyond which the collective impact of multiple surveillance approaches constitutes a search.
• Data collected by data brokers, private companies that aggregate data from myriad sources to come up with comprehensive pictures of individuals’ demographics and preferences. If some of the news stories about data brokers are accurate, these companies have amazingly detailed information. Could it be a “search” for an officer to access a suspect’s profile or dossier?

Further reading. Professor Orin Kerr is the leading scholar in this area, and various articles of his were cited in four of the five opinions. He’s blogging about the case at the Volokh Conspiracy. His first post is here. Jessie Smith’s preview of the case is in this prior post.

Further discussion. I would love to hear others’ perspectives on this case and its implications. Please share your view in the comments — or send me an email directly if you prefer.