The U.S. Supreme Court’s 5-4 decision in Carpenter v. United States, ruling that the collection of historical cell-site location information (CSLI) during criminal investigation is a search under the Fourth Amendment, was seen as a vindication for those arguing for higher privacy standards. CSLI data allows law enforcement authorities to roughly estimate the location of a cell-phone holder over potentially long periods of time.
But the court was clear that this case should not influence Fourth Amendment considerations in other types of situations. “Our decision today is a narrow one,” wrote Chief Justice John Roberts Jr. in the majority opinion.
He noted the court “does not express a view on matters not before us,” such as whether real-time downloading information on multiple devices from a single cell tower requires a warrant, or the application of “conventional surveillance techniques and tools.” He added, “our opinion does not consider other collection techniques involving foreign affairs or national security.”
Still, legal experts believe that the way the opinion approaches CSLI data and grants it an exemption under the “third party doctrine”—which holds there is no reasonable right to privacy when data is voluntarily provided to a third party—means the ruling will have lasting impact on privacy cases for years to come.
“Regardless of what constraints the court tried to build into the opinion, I think it will have rather sweeping implications for other types of digital information,” said Michael Vatis, a partner at Steptoe & Johnson. “But what those implications are will really be left for the lower court and the Supreme Court” to decide.
Why CSLI Stands Apart
At the heart of the ruling is way the majority opinion considers CSLI data different than other types of information under the Fourth Amendment. In Smith v. Maryland and United States v. Miller, the court held that the collection of telephone numbers and bank records by law enforcement authorities do not constitute searches because they are voluntarily handed over to third parties by their owners.
“But while the third-party doctrine applies to telephone numbers and bank records, it is not clear whether its logic extends to the qualitatively different category of cell-site records,” Roberts wrote. He added, “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.”
Roberts goes on to note, as the court first did in Riley v. California, that cell phones have become a pervasive, indispensable technology for most Americans, akin to a part of human anatomy, and that while CSLI data is less accurate than GPS data, it chronicles persons every movement, indefinitely.
Equally as important, he argues that CSLI data is not voluntarily given, but instead automatically generated so long as the phone is on and in use. “Apart from disconnecting the phone from the network, there is no way to avoid leaving behind a trail of location data,” Roberts wrote.
The court’s description of why historical CSLI data is different under the Fourth Amendment and the third party doctrine strikes some as formative. Daniel Castro, vice president at the Information Technology and Innovation Foundation (ITIF), believes other courts will use the Carpenter opinion to be more discerning about what type of data collections constitute a search.
“I think they will have to consider the nature of the data in the specific context of what it reveals, how it was collected, what the consumer knew about it, and how many others collect that same information,” Castro said.
But there are still many questions about how Carpenter could be applied more broadly. “I think it will be very interesting to see how this opinion is applied to a grayer area, which is collection of geolocation data by the various apps running on all on these phones that the court says is indispensable to the participation of modern society,” said Laura Jehl, partner at Baker Hostetler.
She noted that if certain mobile apps were deemed to be indispensable as well, it is not clear how all the data they may passively collect would be treated by future courts.
“Where is the line? How much do you have to have consent, how much voluntariness is required for geolocation data? Because what your cell phone is really collecting about you and sharing with private companies in most instances is a lot more detailed” than CSLI.
Castro agreed, adding that such determinations are “very subjective, which means it’s going to be very hard for the courts to say, ‘OK, this data is more sensitive than financial records.’ But how much more over line does it go in terms of consumer privacy?”
How CSLI ‘Broke the Equilibrium’
The Supreme Court’s Carpenter opinion did stress that the time during which geolocation data was collected does play a large role in determining whether the collection is a search, echoing a long legal precedent in Fourth Amendment cases.
The Supreme Court, for example, noted that limited GPS tracking in United States v. Knotts did not constitute a search, but ruled GPS tracking over a period of 28 days did constitute a search in United States v. Jones. In Carpenter, the court specifically set seven days — far less than the 127 days of data that was collected by the government defendants — as a limit when collecting CSLI data, after which the collection would be considered a search.
Vatis noted that this issue of time ties into how invasive tracking can be, and into people’s general expectations of privacy. “In the previous cases like Knotts, the court was able to say that a tracking device did not constitute a search because law enforcement could just simply follow a person around and the tracking device was just an aid to that.”
But with digital surveillance, “that analogy to physical surveillance falls apart, because law enforcement typically doesn’t follow people for such extended periods of time. And that’s why the practice of relying on the CSLI for a certain period kind of broke the equilibrium,” he said.
While the court also stressed that its ruling only applies to CSLI data and not conventional surveillance, there are questions of if that will change should conventional surveillance become more invasive. As an example, Vatis pointed to a situation where a crime has been committed in a public space like New York City’s Time Square, and the police collect recordings from security cameras in the area, which would likely not constitute a search under legal precedent.
“But what if a couple of years from now, the government has rolled out some system connecting all those security cameras to centralized database that allows it to follow someone over the course of a broad distance and a long time? Would the court then say, ‘OK in that situation, you do need a warrant’? The equilibrium of privacy has changed; technology has now given the government an intrusive search capability.”
Whether the Carpenter opinion acts as a Fourth Amendment privacy check on such surveillance is a question only time will tell. But it’s unmistakable that after Carpenter, courts will begin treating telecommunications far differently than they did any other information. “There is a world of difference between the limited types of personal information addressed in Smith and Miller,” Roberts wrote, “and the exhaustive chronicle of location information casually collected by wireless carriers today.”
The views expressed in the article are those of the authors and not necessarily the views of their clients or other attorneys in their firm.