Barry Kamins

In a landmark decision significantly affecting digital privacy, the United States Supreme Court, in Carpenter v. U.S., 585 U.S. ___, has held for the first time that a person has an expectation of privacy in the whole of his or her physical movements. In addition, it reframed the 40 year-old third party doctrine to permit a person to maintain privacy rights even though he has shared information with a third party, when the information is uniquely sensitive and personal.

The court also made clear that it will step in, when necessary, to ensure that the government’s power does not become excessive because of “seismic shifts in digital technology.” (Slip Op at 15). In the last few years the court has attempted to do so in the area of GPS surveillance (U.S. v. Jones, 565 U.S. 400 (2012)) and cell phone searches (Riley v. California, 573 U.S. ___ (2014)); search warrants are now required for both procedures. It has now held that when law enforcement seeks historical cell site location information (CSLI), this constitutes a search which, with a few exceptions, will also require a search warrant.

In 2011, the police arrested four men suspected of robbing proprietors in, ironically, a series of cell phone stores in Detroit. One of the men confessed that the group, along with as many as 15 other men, had robbed nine different stores in Michigan and Ohio. He gave the FBI the cell numbers of some accomplices, one of whom was Timothy Carpenter.

FBI agents then applied for court orders under the Stored Communications Act to obtain Carpenter’s historical cell site records for a total of 127 days. Agents recovered CSLI from two wireless carriers used by Carpenter—this information revealed the location of Carpenter’s phone, establishing that he was near the scene of four of the robberies. Based on that information and other evidence, Carpenter was convicted.

Carpenter had argued that the seizure of the cell phone records violated the Fourth Amendment because they had been obtained without a warrant supported by probable cause. The District Court denied the motion and, after conviction, the ruling was affirmed by the Sixth Circuit Court of Appeals.

In reversing, the Supreme Court held that accessing at least seven days or more of a person’s historical cell site records constitutes a search under the Fourth Amendment. It is deemed to be a search because a person maintains a legitimate expectation of privacy in the record of his physical movements. Absent exigent circumstances, a search warrant is required.

The court explained that accessing historical cell site records violates a reasonable expectation of privacy because it is the type of monitoring that gives the government the power of “near perfect surveillance, as if it had attached an ankle monitor to the phone’s user.” (Slip Op at 13.) This surveillance is “detailed, encyclopedic and effortlessly compiled.” (Slip Op at 10.) In addition, mapping a cell phone’s location over the course of 127 days provides an all-encompassing record of the phone user’s whereabouts.

Having established that an individual has a legitimate expectation of privacy, the court then addressed whether that expectation can be negated by an application of the third party doctrine. Under that doctrine, a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties.

The doctrine has been a bright line rule for the past 40 years, tracing its roots to two cases involving bank records (U.S. v. Miller, 425 U.S. 435 (1976)) and the records of dialed telephone numbers (Smith v. Maryland, 443 U.S. 735 (1979)). Pursuant to the doctrine, the government is free to obtain such information from the recipient without triggering Fourth Amendment protection.

The court declined to apply Miller and Smith to the unique nature of CSLI, and held that the third party doctrine cannot diminish an expectation of privacy in records that are vastly more revealing and sensitive than the records obtained in Miller and Smith. In determining whether the doctrine was applicable, the court needed to address both the nature of the information being conveyed and whether the conveyance of the information is voluntary.

First, the court held that a phone user does not, in any meaningful sense, “voluntarily” give location information to wireless carriers. Virtually any activity on the phone generates CSLI, and apart from disconnecting the phone, there is no way to avoid leaving behind a trail of location data. In addition, conveying location information does not require an affirmative act by a cell phone user. Second, CSLI is “qualitatively different” from the records disclosed in Miller and Smith, which revealed much less personal information. Thus, the third party doctrine was not applicable to CSLI.

Chief Justice Roberts, who wrote the majority opinion in a 5-4 decision, described the decision as a “narrow” one that will not apply to real-time CSLI, conventional surveillance techniques, such as security cameras, or other collection techniques involving foreign affairs or national security.

In addition, a search warrant will not be required when exigent circumstances exist such as the need to pursue a fleeing suspect, the protection of individuals who are threatened with imminent harm, or a response to emergencies involving bomb threats or child abductions.

Certain questions remain unanswered by Carpenter. The court held that accessing at least seven days of CSLI will constitute a search, thus requiring a search warrant. It declined to decide whether a more limited acquisition of CSLI should escape Fourth Amendment scrutiny. What if a prosecutor seeks CSLI for a period of less than seven days? Could prosecutors continue to obtain those records by a court order under the Stored Communication Act?

Prior to Carpenter, several New York appellate courts had the opportunity to address the accessing of short-term CSLI. In People v. Hall, 86 A.D.3d 450, the First Department upheld the acquisition of CSLI over a three-day period without a warrant, holding that the defendant had no reasonable expectation of privacy. The Fourth Department has upheld the warrantless seizure of CSLI over a four-day period but came to that conclusion only after applying the third party doctrine. People v. Jiles, 158 A.D.3d 75 (2017). While the rationale of these decisions has been rejected by Carpenter, it is still an open question whether accessing short-term CSLI constitutes a search.

Other questions remain unanswered as well. To what extent will Carpenter be applied retroactively? If one assumes that Carpenter has announced a “new rule,” one could argue that it will not be applied to cases already decided but only to cases pending on direct review. Chaidez v. U.S., 568 U.S. 342.

While the Supreme Court describes its decision as a “narrow” one, many believe that Carpenter will have far-reaching implications by protecting other forms of electronic information. One immediate impact may be on the acquisition of emails.

In United States v. Warshak, 631 F. 3d 266 (6th Cir. 2010), the Sixth Circuit held that the government violated the defendant’s Fourth Amendment rights by seizing about 27,000 emails without a warrant. The court refused to apply the third party doctrine and held that the defendant had a reasonable expectation of privacy in his emails. The rationale in Warshak has now been validated by Carpenter.

Carpenter may have an impact on information stored in other databases from which a person’s location can also be inferred. Automated license plate readers, E-Z Pass and credit card records, for example, can generate inferences about a person’s location that may even be more precise that CSLI.

Finally, Carpenter may have an impact on emerging technologies that can store the most sensitive type of information, e.g., voice activated digital assistants (ALEXA); family genealogy records, etc. As Chief Justice Roberts noted, however, the court does not “begin to claim all the answers today,” and in quoting former Justice Felix Frankfurter, reminded us that the court must tread carefully to “ensure that we do not embarrass the future.” Northwest Airlines v. Minnesota, 322 U.S. 292 (1944).


Barry Kamins is a partner at Aidala, Bertuna & Kamins and author of ​’New York Search and Seizure’ (Lexis/Nexis 2018). He is a former ​State Supreme Court Judge.