“Categorically unconstitutional” – that is how the US Fifth Circuit Court of Appeals has ruled about the use of geofence warrants.

The part of the Constitution that this type of warrant, that enables dragnet-style mass surveillance, violates is the Fourth Amendment, the court found.

This amendment is meant to protect citizens from unreasonable searches or seizures – but, said the court of appeals, what geofence warrants do is allow for the opposite: “General, exploratory rummaging.”

We obtained a copy of the ruling for you here.

Geofencing works by essentially treating everyone who happens to be in a geographic area during a given time as a suspect, until established otherwise.

And, the Electronic Frontier Foundation (EFF), a digital rights group, an outspoken critic that often gets involved in legal cases to argue against this method of investigation, welcomed the court’s decision, noting that people should not have to fear having their phone with them in public because that could turn them into a criminal suspect.

The Circuit Court’s stance on geofence warrants came as it deliberated the United States v. Smith case, revolving around the police in Mississippi in 2018 resorting to obtaining this type of warrant to investigate an armed robbery and assault that took place in a post office.

Google, which is who law enforcement turns to with these warrants most of the time, obliged, turning over data from the phones to the police, who then managed to produce two suspects, later defendants.

But – even though it decided not to suppress the evidence, because it found the police were acting “in good faith” while geofencing was still a new phenomenon – the Fifth Circuit Court doesn’t think the warrants are inherently lawful, i.e., in compliance with the Constitution.

One problem cited by the judges is that police access to sensitive location data collected during the process of geofencing is “highly invasive” since it can reveal a lot about a person, including their associations, and, also lets the police “‘follow’ them into private spaces,” EFF explained the court’s decision.

Another is that the warrants never specify that they apply to a particular person, as law enforcement “have no idea who they are looking for, or whether the search will even turn up a result.”