How To Use Geofence Warrants In A Constitutional Manner

By Robert Frommer | September 6, 2024, 3:07 PM EDT ·

Robert Frommer
Robert Frommer
Geofence warrants are powerful tools that let law enforcement identify devices located at a specific location and time based on data users send to Google LLC and other tech companies. But left unchecked, they threaten to empower police to invade the security of millions of Americans. Thankfully, there is a way that geofence warrants can be used in a constitutional manner, if only courts would take it.

First, a bit about geofence warrants. Google, the company that handles the vast majority of geofence warrants, follows a three-step process when it receives one.

Google first searches its location database, Sensorvault, to generate an anonymized list of devices within the geofence. At Step 2, police review the list and have Google provide broader information for a subset of devices. Then, at Step 3, police have Google unmask device owners' identities.

Google came up with this process itself. And a court does not decide what information gets turned over at Steps 2 and 3. That is negotiated by the police and Google. These warrants are issued in a wide span of cases, including not just ordinary crime but also investigations related to the Jan. 6, 2021, insurrection.

One court has held that none of this implicates the Fourth Amendment. In July, the U.S. Court of Appeals for the Fourth Circuit held in U.S. v. Chatrie that demanding location data was not a "search."

It reasoned that, under the third-party doctrine, people lose constitutional protection in information they voluntarily share with others. Since users share location data, the Fourth Circuit said the Fourth Amendment does not protect it at all.

That reasoning is highly suspect. The Fourth Amendment is meant to secure our persons and property. If I take my car to the mechanic, for example, police could not search it on a whim. The car is still mine; I just gave it to the mechanic for a limited purpose — getting it fixed — and the mechanic agreed to secure the car as part of that.

As a constitutional matter, personal data should be treated the same. We give our data to Google for a specific purpose — getting location services — and Google agrees to secure it.

But under the Chatrie decision, that seemingly does not matter. Its holding leaves the location data of hundreds of millions of users completely unprotected, meaning police could order Google to tell them anyone's or everyone's location, whenever they want.

Things could not be more different in the U.S. Court of Appeals for the Fifth Circuit.  The Fifth Circuit held in its Aug. 9 decision in U.S. v. Smith that geofence warrants do require a "search" of users' property. It rebuked Chatrie's invocation of the third-party doctrine, concluding that users do not share location data in any "voluntary" sense.

So far, so good. But the Fifth Circuit went further. It recognized that, at Step 1, Google must search through every account in Sensorvault. That kind of broad, indiscriminate search of every user's data is unconstitutional, said the court, likening geofence warrants to the general warrants the Fourth Amendment prohibits.

So, as of now, police can demand location data at will in some states. And in others, police cannot get that data at all.

The Fifth Circuit was correct in holding that, as currently designed and executed, geofence warrants are unconstitutional. But that doesn't mean they can never be executed in a constitutional manner.

The geofence warrant process can be refined so that courts can safeguard our rights while letting the police investigate crime.

That refinement begins with the courts. Recall that, after issuing a geofence warrant, courts check themselves out from the process, leaving Google to fend for itself. But courts, not corporations, should safeguard our rights. That means geofence warrants require an iterative process that ensures judicial oversight at each step.

Under that iterative process, courts would still issue geofence warrants. But after Step 1, things would change. Rather than go to Google, the police would return to court. They would identify what devices from the Step 1 list they want expanded location data for. And they would have to justify that further intrusion to the court, which would then evaluate the request and denote the subset of devices for which police could constitutionally get expanded data.

The same would happen at Step 3. Rather than police demanding Google unilaterally unmask users, police would ask the court for a warrant asking Google to do that. To get that warrant, police would need to show probable cause linking those individuals and specific devices to the crime under investigation.

Getting courts to actively monitor and control the geofence process is imperative. These warrants have led to innocent people being arrested for crimes they did not commit. And if demanding location data from Google is not even a search, then police can rummage through them as they wish.

The Fourth Amendment was enacted to protect us against "general warrants" that gave officials a blank check to invade our security. We must ensure we don't inadvertently allow the modern-day digital equivalent to do the same.

Geofence warrants are uniquely powerful and present unique concerns. To address those concerns, courts need to be in charge. By treating digital information as property and instituting an iterative process, we can ensure that geofence warrants are narrowly tailored, minimize infringements on innocent individuals' rights, and uphold the principles underlying the Fourth Amendment.



Robert Frommer is a senior attorney at The Institute for Justice.

"Perspectives" is a regular feature written by guest authors on access to justice issues. To pitch article ideas, email expertanalysis@law360.com.


The opinions expressed are those of the author(s) and do not necessarily reflect the views of their employer, its clients, or Portfolio Media Inc., or any of its or their respective affiliates. This article is for general information purposes and is not intended to be and should not be taken as legal advice.

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