By: Franklin Sandrea-Rivero, J.D. Candidate, May 2019, St. Thomas University School of Law.

On November 29, 2017, the United States Supreme Court heard oral arguments in the case of Carpenter v. United States. This case arose out of a series of robberies involving the theft of hundreds of cellphones. But the issue in this case was not whether the defendant, Timothy Carpenter, was guilty of being the criminal mastermind behind the cellphone thefts. The issue here was whether prosecutors were justified in using Mr. Carpenter’s Historical Cell Site Location Information (CSLI)—which allowed for the matching of Mr. Carpenter’s general location to that of the robbery locations—to help convict him.

Everytime a cellphone user sends and receives telephone calls, text messages, or email communications, they generate CSLI. CSLI is location data that is generated and transmitted to the nearest available cell phone tower. Although its intended purpose is to allow cellphone companies the ability to manage their cellphone networks, law enforcement and prosecutors have been using CSLI in criminal investigations and criminal trials to establish a defendant’s whereabouts during a commission of a crime. The use of CSLI in criminal trials creates implications for the Fourth Amendment as questions arise as to whether law enforcement require a search warrant to obtain CSLI.

The Fourth Amendment guarantees “the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures.” U.S. Const. amend. IV. “[A] party alleging an unconstitutional search under the Fourth Amendment must establish both a subjective and an objective expectation of privacy [in the object of the search] to succeed.” United States v. Robinson, 62 F.3d 1325, 1328 (11th Cir. 1995). A party who voluntarily conveys information to a third-party will fail in establishing a Fourth Amendment search violation. This is because according to the third-party doctrine, an individual who voluntarily conveys information to a third party has assumed the risk that the third party will subsequently convey that information to the government and therefore, has no subjective nor objective expectation of privacy in said information. See Smith v. Maryland, 442 U.S. 735, 743 (1979); see also United States v. Miller, 425 U.S. 435, 443 (1976). Thus, the major question in Carpenter, and every other case whereby the defendant’s guilt hinges in part, on CSLI evidence, is whether the third-party doctrine should apply to CSLI.

Proponents advocating for the applicability of the third-party doctrine to CSLI argue that cellphone users voluntarily convey their location information to cellphone companies because they are generally aware that their cellphone pings their location information to cell-network towers everytime they use their cellphones. Proponents advocating for the applicability of the third-party doctrine also argue that because cellphone contracts contain language asserting that the company will collect CSLI, that cellphone users should not be surprised if their CSLI data winds up in the hands of law enforcement.

Opponents argue that the third-party doctrine should not apply to CSLI data since CSLI is generated even when the cellphone user does not actively use their phone by placing calls or sending text messages. This is because CSLI is also generated when cellphone users receive calls or text messages. Thus, the voluntariness requirement for the third-party doctrine is absent in these instances.

So far, the majority of circuits have been willing to extend the third-party doctrine to CSLI. However, several justices expressed concern for that proposition during oral arguments in Carpenter. For example, Chief Justice Roberts disagreed with the notion that cellphone users voluntarily convey CSLI because they choose to get a phone, and know that their CSLI will be stored by their cellphone provider as soon as they sign the contract. Chief Justice Roberts particularly noted that that cellphones have become more ubiquitous over the last decade and a half, and that having one is “not a matter of choice in the modern digital world.” Justice Sotomayor noted that “cellphones are different.” Her statement alludes to the fact that the cases in which the third-party doctrine rests did not have cellphones and the technological advances that come with it in mind when these cases were decided. Specifically, the Court in Smith v. Maryland found that telephone users do not have an expectation of privacy in the numbers they dialed on their telephone.  In United States v. Miller, the Court also found that people do not have an expectation of privacy in their bank records.

Cellphones, as Justice Sotomayor, correctly pointed out, are different in that users are attached to them wherever they go. The question then turns into whether people have an expectation of privacy in their location over a period of several days or even months. In the case of Mr. Carpenter, the government used 127 days’ worth of CSLI data to help convict him.  By extending the third-party doctrine to CSLI records, the Court is essentially saying that the government can track you over several months and find out intimate details of your live—details the 4th Amendment was designed to protect. They can, because of your use of a  cellphone, figure out where you live, where you go to school, what you had for lunch at 1 o’clock in the afternoon, where you go to see your doctor, and all without obtaining a search warrant.

Virtually no case has upended nor restricted the third-party doctrine since its genesis four decades ago, will Carpenter be the first?