Court: Cellular GPS, location data requires a warrant


In a court case in front of the U.S. Court of Appeals, the judges ruled unanimously that the defendant’s cellular GPS and other location data could not be legally obtained without first getting a search warrant. This case, United States v. Davis is being hailed by privacy advocates as a major victory.

The location information in this case came from the cell phone carrier, which law enforcement received without providing just cause. The challenge to the guilty conviction was based primarily on the argument that the evidence that placed the defendant at the scene of the crime was taken in violation of the Fourth Amendment.

As a refresher, the Fourth Amendment reads as follows:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

In short, this requires the government to convince a court they have good reason before performing a search on someone’s property or otherwise violating their privacy. In legal practice, evidence gained by violating the fourth amendment is inadmissible in court. This amendment was motivated in part due to the fact that in colonial America, there was no such amendment; British authorities frequently searched the homes and business of colonists without warning or explanation.

Judge David Sentelle, who wrote the opinion on this case, explained that as technology has advanced, the Supreme Court’s opinions have begun to expand the scope of the Fourth Amendment beyond the idea of protecting one’s property from trespass but also one’s privacy more generally.

The key legal precedent in this case, as explained in the opinion, is United States v. Jones, which was decided in 2012. In that case, the Supreme Court ruled that placing a GPS on someone’s car without a warrant was an unlawful invasion of their privacy and akin to a warrantless search.

The Jones decision is important in regard to tracking of citizen locations because one part of privacy law is that what can be seen publicly is not protected by the Fourth Amendment. For instance, if the police suspected that I left incriminating evidence in a corn field, they could go look for it there without a warrant since it is a space in plain view of the public. The government in the Jones case argued that GPS tracking the defendant’s car was not a warrantless search since we only drive our cars in public.

In that case, the opinion said the issue is “not one of degree but kind,” which is to say that what is publicly viewable by happenstance is not the same as systematically collecting all public activities of a person. It is, as they say, the difference between “a day of life” and “a way of life.” Law enforcement has no right to learn someone’s way of life without a warrant. There is no reasonable expectation of privacy on your trip to Wal-Mart, but there is a reasonable expectation of privacy for the entirety of your travels.

Law enforcement has no right to learn someone’s way of life without a warrant.

The difference in Davis is that law enforcement did not attach a device or use some sort of extensive monitoring to obtain the defendant’s location. Instead, they used location data that exists in phone records – at any given time, your cell phone may communicate with a cell tower, especially when making phone calls. While it is not as precise as GPS, it is possible to know someone’s proximity and direction from the tower.

While Jones was an example of trespass due to the placement of the device, Davis is decided based on the notion of privacy alone since the location information was generated by the defendant’s cell phone. We’ll let Judge Sentelle explain the key portion of this decision:

One’s car, when it is not garaged in a private place, is visible to the public, and it is only the aggregation of many instances of the public seeing it that make it particularly invasive of privacy. . . the car owner can reasonably expect that although his individual movements may be observed, there will not be a “tiny constable” hiding in his vehicle to maintain a log of his movements. . . One’s cell phone, unlike an automobile, can accompany its owner anywhere. Thus the exposure of the cell site location information can convert what would otherwise be a private event into a public one.

While it would be great if cellular carriers didn’t store this sort of information at all, it is much better for consumer privacy that law enforcement will now have to ask for a warrant before obtaining this type of information. Nobody wants to feel like they are walking around with a tracking device in their pocket.

The court soundly repudiates the government’s argument that by merely using a cell phone, people somehow surrender their privacy rights.

The American Civil Liberties Union, who argued on behalf of the defendant, hailed the decision. The ACLU Staff Attorney said in reaction, “This opinion puts police on notice that when they want to enlist people’s cell phones as tracking devices, they must get a warrant from a judge based on probable cause. The court soundly repudiates the government’s argument that by merely using a cell phone, people somehow surrender their privacy rights.”

Featured image by Institute for Money, Technology, and Financial Inclusion (Flickr).

Tags: Aclu Appeals Court Fourth Amendment Privacy Smartphones Supreme Court Technology