The United States Court of Appeals for the Fifth Circuit has overturned a previous ruling, concluding geofence warrants are “categorically prohibited by the Fourth Amendment.”

A three-judge panel—Judges Carolyn Dineen King, James C. Ho, and Kurt D. Engelhardt—overturned a ruling by the Fourth Circuit to conclude that geofence warrants are unconstitutional.

We hold that the use of geofence warrants—at least as described herein—is unconstitutional under the Fourth Amendment. In doing so, we part ways with our esteemed colleagues on the Fourth Circuit.

What Is A Geofence Warrant?

Geofence warrants are a relatively new type of warrant in which law enforcement tries to identify random individuals within a geographic area based on Google Location History data.

For example, when a crime is committed, law enforcement may approach Google and ask for anonymized identifiers for all phones within a certain radius of the crime at the time it was committed. With that data in hand, investigators can drill down, comparing it with other evidence and eventually identify the owners of specific devices, yielding potential suspects.

As the judges point out, Google is the primary recipient of goefence warrants since it received the first one in 2016. Much of this is because of the ubiquity of Google’s software and services, both on its own devices as well as Apple’s.

So far, Google has been the primary recipient of geofence warrants, in large part due to its extensive Location History database, known as the “Sensorvault.”

Google collects data from accounts of users who opt in to Google’s Location History service. Location History is disabled by default.

Google’s Android cell phones, which “comprise about 74% of the total number of smartphones worldwide,” “automatically have an Android operating system, as well as various Google apps that could potentially store a user’s location.”

Apple, which makes approximately 23% of the world’s smartphones, does not keep location data associated with its phones, but its phones still “often have various apps that . . . provide Google with a specific device’s location.”

The judges go on to describe the extremely detailed data provided by Google’s Location History.

Moreover, not only is the volume of data comprehensive, so is the quality. “Location History appears to be the most sweeping, granular, and comprehensive tool—to a significant degree—when it comes to collecting and storing location data.”

The data is “considerably more precise than other kinds of location data, including cellsite location information because [Location History] is determined based on multiple inputs, including GPS signals, signals from nearby Wi-Fi networks, Bluetooth beacons, and cell towers.”

Why Geofence Warrants Are Problematic

Geofence warrants can and do lead to innocent people being suspected of crimes. A person may be in the wrong place at the wrong time, and suddenly find themselves at the heart of an investigation. Similarly, a person may have lost their phone, forgotten it, or had it stolen, all of which could result in someone’s phone being within a geofence area, even if the owner is not.

Even more concerning is the vast amount of private data that is vacuumed up in a geofence warrant, with the location data of users who have nothing to do with the crime being collected and analyzed, all with no probable cause.

As federal judge Nina Morrison said in a recent ruling about the Fourth Amendment’s application at the US border, a person’s location data hold extremely private insights into a person’s personal life, associations, and beliefs:

In Carpenter v. United States, 585 U.S. 296, 311–12 (2018), the Court concluded that cell-site location data, even though it is collected by (and thus not kept private from) third party cell phone companies, requires Fourth Amendment protection for precisely this reason….It reasoned that cell-site location data “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 his ‘familial, political, professional, religious, and sexual associations.’”

The Legal Precedent

Interestingly, in the specific case before the Fifth Circuit—the robbery of a contracted US Postal carrier—the judges decided not to suppress the information that law enforcement collected via a geofence warrant. Because geofence warrants were so new at the time they were used in this specific case, the judges ruled the Postal Inspectors “acted in good faith” in using the warrant.

Nonetheless, the judges looked at the broader scope of the geofence warrant issue and analyzed whether such warrants violate the Fourth Amendment’s guarantee against “unreasonable searches and seizures.” The judges then pointed to the precedent set by the Supreme Courts decision in Carpenter v. United States, “arguably the most relevant Supreme Court precedent addressing law enforcement’s investigatory use of cellular consumer data.

Chief Justice Roberts’s majority opinion in Carpenter speaks at length about the privacy interests inherent in location data, and it expresses grave concern with the government being able to comprehensively track a person’s movement with relative ease due to the ubiquity of cell phone possession. The Court acknowledged “some basic guideposts” in resolving questions related to the Fourth Amendment’s protections of privacy interests, including securing “the privacies of life against arbitrary power,” and placing “obstacles in the way of a too permeating police surveillance.” Carpenter, 585 U.S. at 305 (internal quotations omitted). The Court also recognized the necessity of applying the Fourth Amendment to systems of advanced technology, expressing concern that CSLI is approaching “GPS-level precision,” with wireless carriers having the capability to “pinpoint a phone’s location within 50 meters.” Id. at 313; see also Riley v. California, 573 U.S. 373, 396 (2014) (acknowledging the privacy concerns implicated by cell phone location data that “can reconstruct someone’s specific movements down to the minute, not only around town but also within a particular building”).

Many of the concerns expressed by Chief Justice Roberts in his Carpenter opinion are highly salient in the context of geofence warrants. Perhaps the most alarming aspect of geofences is the potential for “permeating police surveillance.” As Chief Justice Roberts explained, modern cell phones enable the government to achieve “near perfect surveillance”; carrying one of these devices is essentially a prerequisite to participation in modern society, and users “compulsively carry cell phones with them all the time.” Id. at 311–12, 315. Geofences also exemplify the Court’s concern with pinpoint location data—this technology provides more precise location data than either CSLI or GPS. Geofence Warrants and the Fourth Amendment, supra at 2510. Furthermore, obtaining data through geofences, like obtaining data through CSLI, is “remarkably cheap, easy, and efficient compared to traditional investigative tools.” Carpenter, 585 U.S. at 311. With “just the click of a button,” the government can search the pinpoint locations of over half a billion people with Location History enabled.

The Court’s Conclusion

After carefully considering all of the above factors, as well as how hard it is to keep Google from collecting Location History, the judges revealed their ruling.

Having concluded that the acquisition of Location History data via a geofence is a search, it follows that the government must generally obtain a warrant supported by probable cause and particularity before requesting such information. Carpenter, 585 U.S. at 316. Accordingly, we turn to the issue of whether geofence warrants satisfy this mandate, addressing Appellants’ argument that these novel warrants resemble unconstitutional general warrants prohibited by the Fourth Amendment.

The judges then drive the point home in their comparison of geofence warrants and illegal general warrants.

Geofence warrants present the exact sort of “general, exploratory rummaging” that the Fourth Amendment was designed to prevent.

The judges also addressed the governments assertion that geofence warrants should be exempt since they pertain “to a particular crime at a particular place and time.”

This argument misses the mark. While the results of a geofence warrant may be narrowly tailored, the search itself is not. A general warrant cannot be saved simply by arguing that, after the search has been performed, the information received was narrowly tailored to the crime being investigated. These geofence warrants fail at Step 1—they allow law enforcement to rummage through troves of location data from hundreds of millions of Google users without any description of the particular suspect or suspects to be found.

In sum, geofence warrants are “[e]mblematic of general warrants” and are “highly suspect per se.”

We hold that geofence warrants are modern-day general warrants and are unconstitutional under the Fourth Amendment. However, considering law enforcement’s reasonable conduct in this case in light of the novelty of this type of warrant, we uphold the district court’s determination that suppression was unwarranted under the good-faith exception.

The Decision Will Hamper Law Enforcement

In a concurring opinion, Judge Ho acknowledged that the decision would make law enforcement’s jobs more difficult. Nonetheless, Judge Ho pointed out that this was the entire point of the Constitution.

His concurring opinion is a fascinating look into the balancing act that exists between protecting the public, while also protecting the rights of the individual. His opinion bears being included in its entirety.

Geofence warrants are powerful tools for investigating and deterring crime. The defendants here engaged in a violent robbery—and likely would have gotten away with it, but for this new technology. So I fully recognize that our panel decision today will inevitably hamper legitimate law enforcement interests.

But hamstringing the government is the whole point of our Constitution. Our Founders recognized that the government will not always be comprised of publicly-spirited officers—and that even good faith actors can be overcome by the zealous pursuit of legitimate public interests. “If men were angels, no government would be necessary.” The Federalist No. 51, at 349 (J. Cooke ed. 1961). “If angels were to govern men, neither external nor internal controls on government would be necessary.” Id. But “experience has taught mankind the necessity of auxiliary precautions.” Id. It’s because of “human nature” that it’s “necessary to control the abuses of government.” Id.

Our decision today is not costless. But our rights are priceless. Reasonable minds can differ, of course, over the proper balance to strike between public interests and individual rights. Time and again, modern technology has proven to be a blessing as well as a curse. Our panel decision today endeavors to apply our Founding charter to the realities of modern technology, consistent with governing precedent. I concur in that decision.