The Supreme Court of the United States ruled, in June, in the case Carpenter v. the United States, by majority vote, that government entities must obtain a warrant to access the data/information on the location and movement of suspects of crimes in FBI investigations, on cellphone networks.
The ruling that accepted to try this case before the Supreme Court, in the Certiorari to the United States Court of Appeals for the Sixth Circuit, presented the following issue:
“Whether the warrantless seizure and search of historical cell phone records revealing the location and movements of the cell phone user over the course of 127 days is permitted by the Fourth Amendment.”
Judge Robert cast the winning opinion, which was followed by Ginsburg, Breyer, Sotomayor, and Kagan. Justices Kennedy, Thomas, Alito, and Gorsuch cast the dissenting and defeated opinions.
The Court’s decision mentioned the fact that in the United States there are 396 million cellphone services accounts, within a universe of 326 million people.
The discussion revolved around the interpretation of the Fourth Amendment of the U.S. Constitution.
The American constitutional debate consists of examining whether the search and seizure of data/information on the physical movement of an individual through cell phone networks, requested by the authorities, require a warrant or not.
The issue is whether a third party (in this case, the cell phone companies), has the right to oppose the search of personal data/information.
It also involves the expectation of privacy before third parties (cellphone companies).
The majority opinion pointed out that technological innovations allow for the mass surveillance of the population. Hence the risks of technologies concerning the expectations of privacy of citizens, in violation of the fourth amendment.
By majority vote, the Supreme Court of the United States ruled that there is the expectation of privacy before third parties, namely the cellphone companies.
The U.S. Government invoked the Third-party Doctrine. According to this doctrine, the person has reduced expectation of privacy when information is shared with third parties.
As mentioned, the core issue is the expectation of privacy regarding the historical records on the location of an individual, by the recording of the movement of the respective users by the cellphone companies.
The majority opinion of the Supreme Court presented important considerations. According to the decision:

“The case before us involves the Government’s acquisition of wireless carrier cell-site records revealing the location of Carpenter’s cell phone whenever it made or received calls. This sort of digital data – personal location information maintained by a third party – does not fit neatly under existing precedents. Instead, requests for cell-site records lie at the intersection of two line of cases, both of which inform our understanding of the privacy interests at stake”.

The decision of the Supreme Court of the United States continues:

“Significantly, the Court reserved the question whether ‘different constitutional principles may be applicable’ if ‘twenty-four hour surveillance of any citizen of this country (were) possible.”

The decision also provides considerations on the issue of monitoring via GPS devices installed in vehicles, informing the whereabouts of people.
In this line, the majority opinion of the Court reads:
“A person does not surrender all Fourth Amendment protection by venturing into the public sphere. To the contrary, ‘what (one) seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.
(…)
For that reason, ‘society’s expectation has been that law enforcement agents and others would not – and indeed, in the main, simply could not – secretly monitor and catalog every single movement of an individual’s car for a very long period.
Allowing government access to cell-site records contravenes that expectation. Although such records are generated for commercial purposes, that distinction does not negate Carpenter’s anticipation of privacy in his physical location over the course of 127 days provides an all-encompassing record of the holder’s whereabouts. As with GPS information, the time-stamped data provides an intimate window into a person’s life, revealing not only his particular movements, but through them is ‘familial, political, professional, religious, and sexual associations.’
(…)
Accordingly, when the government tracks the location of a cell phone, it achieves near-perfect surveillance, as if it had attached an ankle monitor to the phone’s user.”
(…)
Moreover, the retrospective quality of the data here gives police access to a category of information otherwise unknowable. In the past, attempts to reconstruct a person’s movements were limited by a dearth of records and the frailties of recollection. With access to CSLI, the Government can now travel back in time to retrace a person’s whereabouts, subject only to the retention policies of the wireless carriers, which currently maintain records for up to five years. Critically, because location information is continually logged for all the 400 million persons in the United States – not just those belonging to persons who might happen to come under investigation – this newfound tracking capacity runs against everyone”.
On the other hand, in the dissenting opinions, which were defeated, the Justices felt that cell phone companies have the right to the property of the users’ historical records.
According to Justice Kennedy’s opinion, the recordings obtained by the government belong to the cell phone companies. Still, according to him, the information on the movement history of the user’s mobile device is not private.
In his dissent, Justice Thomas claimed that the Telecommunications Act is insufficient, and does not grant to the plaintiff the right of ownership of the cell phone networks’ recordings.
Another dissenting opinion highlighted that the Fourth Amendment does not regulate all the methods through which the government can obtain evidence, for criminal investigation.
In sum, the core theme debated by the Supreme Court refers to the reasonable expectation of privacy concerning the data stored by third parties (cell phone companies).
The majority decision was based on a constitutional interpretation of the Fourth Amendment of the American Constitution concerning its purpose, extending the requirement for a warrant to obtain personal information, protecting the person’s expectation of privacy (information on the records of their personal location).
The dissenting opinion, which was defeated, was grounded on a more restrictive and literal interpretation of the Fourth Amendment.
Another issue discussed refers to the right of ownership of the data stored by the cell phone companies.
There are substantial interests at stake, such as the right to include, exclude, and control the use of personal data.
Thus, who owns the data stored through cell phone networks: the users or the phone companies?
According to one of the dissenting opinions, the Telecommunication Act refers solely to the user’s right to privacy of their confidential information concerning the phone company. Thus, the company has a duty to respect the right to privacy of the user’s personal information.
In his vote, Justice Thomas states that the American telephone law does not recognize the right of property of the users concerning the data stored by the telephone companies.
As for the discussion on the interpretation of the Stored Communications Act (the American law applicable to electronic communications), the investigative authority has to show that the information on the personal location obtained through cell phone networks is relevant to the ongoing investigation for it to be admitted as evidence in a criminal case. However, according to the winning decision, this statute is not the proper mechanism for obtaining access to the recordings of cell phones’ location history.
On the other hand, according to the dissenting opinion, the Stored Communication Act authorizes Courts to order that the recorded history be handed over, provided that the government show specific and substantiated facts that such evidence (the recordings) is relevant to the ongoing investigation.
This United States Supreme Court case is relevant from the point of view of the constitutional interpretation of the right to privacy, especially concerning the treatment of data collected, processed, and stored by private companies.
Note that the matter is broader than the case tried by the USA Supreme Court, which was related to the telephony industry (cell phone companies). The issue of the privacy of personal information also has repercussions on financial institutions, credit card companies, digital payment services, e-commerce, and others. Hence the relevance of the theme, with effects to millions of people.