Last month, Data & Society and fifteen scholars filed an amicus brief in Carpenter v. United States, a pending U.S. Supreme Court case.

Mr. Carpenter was convicted of a series of armed robberies, with his cellphone records revealing to police that his physical movements over 127 days had been in proximity to the robberies.

The Fourth Amendment’s “third party doctrine” states that citizens who voluntarily convey information to third parties do not have reasonable expectation of privacy. This allows police to obtain such information from third parties, such as cell telephony providers, and submit it as evidence in prosecutions.

Carpenter v. United States addresses the legality of the warrantless search and seizure of Carpenter’s historical cellphone records under the Fourth Amendment.  It will be argued that

…the “third party doctrine” should not apply to cell site location information because cell phones are not meaningfully voluntary in modern society. Cell site location information contains abundant information about people’s lives, and unfettered police access to it poses a threat to privacy rights.

Evidence will be provided that “95% of Americans that have cell phones cannot reasonably be expected to opt out of owning a cell phone to avoid police searches.”

The scholars observe that cell phones are demonstrably:

• Necessary to participate in the most basic aspects of social and family life;

• Essential public safety infrastructure and personal safety equipment;

• Both necessary to find employment, and an important part of workplace infrastructure;

• Widely used for commerce and banking;

• Key for civic participation;

• Key for enabling better health outcomes;

• Critical to vulnerable populations; and

• Have been recognized as a necessity by the U.S. government in the past.

The case is expected to be heard in the fall of 2017.