A coalition of the nation’s leading privacy and civil liberties advocates has formally petitioned the United States Supreme Court to intervene in the escalating use of "geofence warrants," arguing that these digital dragnets represent a fundamental violation of the Fourth Amendment. The Electronic Frontier Foundation (EFF), the American Civil Liberties Union (ACLU), the ACLU of Virginia, and the Center on Privacy & Technology at Georgetown Law filed a joint amicus brief on Monday, calling for a definitive ruling against a surveillance practice they describe as the modern equivalent of the "general warrants" that once sparked the American Revolution.
The legal challenge centers on the case of Chatrie v. United States, a pivotal matter that could redefine the boundaries of digital privacy in the 21st century. At the heart of the dispute is the use of reverse-location data—where law enforcement, rather than identifying a suspect and seeking their records, identifies a location and time and demands data on every individual present. The advocacy groups contend that this practice turns every citizen with a smartphone into a potential suspect, fundamentally altering the relationship between the state and the individual.
The Technical Mechanism of Geofence Warrants
To understand the constitutional concerns, it is necessary to examine how a geofence warrant operates. Unlike a traditional warrant, which targets a specific person, place, or thing based on probable cause, a geofence warrant begins with a crime but no suspect. Police draw a virtual boundary—a "geofence"—around a specific geographic area during a specific timeframe. They then serve this warrant to a service provider, most frequently Google, demanding the location history data of every device that entered that boundary.
Google’s "Sensorvault" database has historically been the primary target of these requests. This database contains detailed location history for hundreds of millions of users who have "Location History" enabled on their accounts. When Google receives a geofence warrant, it typically follows a three-step process: first, it provides anonymized data for all devices in the area; second, police review the movements of these anonymous "dots" to identify suspicious patterns; and third, the police demand the identifying account information for the specific devices they have deemed relevant.
The coalition’s brief argues that this process is inherently "exploratory rummaging." Because the initial search requires Google to scan its entire database of users to find those within the geofence, the privacy of millions is technically compromised to find a handful of people. Furthermore, the "anonymized" data in the first step is often easily deanonymized, and the sheer volume of innocent bystanders caught in the net is unprecedented in the history of American policing.
The Case of Chatrie v. United States: A Legal Catalyst
The specific case before the Supreme Court, Chatrie v. United States, originated from a 2019 bank robbery in Midlothian, Virginia. Investigating officers, lacking a lead on a suspect, obtained a geofence warrant that forced Google to search its records for any device within a 150-meter radius of the bank during a one-hour window.
The implications of this specific radius were vast. The area encompassed not only the bank but also a church, several private residences, and busy thoroughfares. In total, the warrant compelled Google to search the records of nearly 600 million users to see who was near that specific Northern Virginia crime scene. The data eventually led police to Okello Chatrie, who was subsequently charged. However, the defense moved to suppress the evidence, arguing that the warrant was overbroad and lacked the particularity required by the Fourth Amendment.
The district court in the Chatrie case initially expressed deep concern over the warrant, calling it "unsettling" and noting that it "circumvents the Fourth Amendment’s protections." However, the court ultimately declined to suppress the evidence, citing the "good faith exception," which allows evidence to be used if police believed they were acting legally at the time. The case has since climbed the judicial ladder, with the Supreme Court agreeing earlier this year to address the core constitutional questions it raises.
Chronology of the Geofence Controversy
The rise and potential fall of geofence warrants have followed a rapid trajectory alongside the advancement of smartphone technology:
- 2016–2017: Law enforcement agencies begin experimenting with geofence warrants, primarily targeting Google’s Sensorvault. The number of requests is initially small, numbering in the dozens.
- 2018: The Supreme Court rules in Carpenter v. United States that police generally need a warrant to access cell site location information (CSLI), establishing that individuals have a reasonable expectation of privacy in their physical movements over time.
- 2019: The Midlothian bank robbery occurs, leading to the geofence warrant against Okello Chatrie. This year sees a massive spike in geofence requests, with Google reporting a 1,500% increase in such warrants over two years.
- 2020–2022: Federal and state courts issue conflicting rulings. Some judges begin denying geofence warrants, calling them "digital dragnets," while others continue to approve them for serious crimes.
- December 2023: In a major policy shift, Google announces it will change how Location History data is stored. Instead of keeping the data in its own cloud (Sensorvault), the data will be stored locally on users’ devices. This change, scheduled to be fully implemented by 2025, effectively makes it impossible for Google to comply with mass geofence warrants in the future.
- 2024: The Supreme Court grants certiorari to Chatrie v. United States, signaling its intent to provide a national standard for these types of searches.
Supporting Data: The Scale of Digital Surveillance
The frequency of geofence warrants has grown at a rate that has outpaced legal oversight. According to transparency reports released by Google, the company received approximately 982 geofence requests in 2018. By 2019, that number jumped to 8,396. In 2020, it surpassed 11,500.
The ACLU and EFF highlight that while Google is the most common recipient, they are not the only data brokers in possession of such information. Numerous third-party apps—ranging from weather trackers to games—collect and sell location data to brokers, who in turn can be subpoenaed by law enforcement. The brief warns that even if Google’s technical changes limit one avenue of surveillance, the legal precedent established by the Supreme Court will apply to all forms of "suspicionless" location-based searches.
Data from the Chatrie case reveals the "dragnet" nature of the practice. For a single crime, the movements of 19 people who were near the bank were scrutinized in detail by investigators, despite 18 of them having no connection to the crime. In other cases, geofences have been drawn around entire city blocks during political protests, capturing the identities of thousands of peaceful demonstrators.
Legal Arguments and the Shadow of General Warrants
The amicus brief filed by the coalition draws a direct line between geofence warrants and the "general warrants" of the colonial era. Before the American Revolution, British authorities used "writs of assistance" to conduct broad searches of colonial homes and businesses without specific evidence of wrongdoing. These intrusive, non-specific searches were a primary grievance of the Framers and led directly to the drafting of the Fourth Amendment.
"This is not traditional police work, but rather the leveraging of new and powerful technology to claim a novel and formidable power over the people," the brief states. The groups argue that for a warrant to be constitutional, it must satisfy two main criteria: probable cause and particularity. Geofence warrants, they argue, fail both. They lack probable cause because they do not target a specific person suspected of a crime; instead, they hope to find a suspect within a crowd. They lack particularity because they do not describe the person or thing to be seized with specificity, instead seizing data from everyone in a given area.
Andrew Crocker, the EFF Surveillance Litigation Director, emphasized this point in a statement following the filing. "To courts, to lawmakers, and to tech companies themselves, EFF has repeatedly argued that these high-tech efforts to pull suspects out of thin air cannot be constitutional, even with a warrant," Crocker said. "The Supreme Court should find once and for all that geofence searches are just the kind of impermissible general warrants that the Framers of the Constitution so reviled."
Broader Implications for Privacy and Democracy
The outcome of Chatrie v. United States will have profound implications for the future of privacy in the United States. If the Supreme Court upholds the use of geofence warrants, it could open the door for even more invasive forms of technology-driven policing. This could include "keyword warrants," where police demand the identities of everyone who searched for a specific term online, or "facial recognition dragnets," where cameras scan entire crowds to find a single face.
Conversely, a ruling against geofence warrants would reinforce the "Carpenter" doctrine—the idea that the digital age requires a robust interpretation of the Fourth Amendment to protect citizens from "the power of technology to shrink the realm of guaranteed privacy."
The brief also cautions the Court against viewing the issue through a narrow lens based on Google’s recent technical changes. While Google’s shift to on-device storage (set for completion in July 2025) may mitigate the immediate use of geofences against their specific database, the legal principle remains vital. Other companies, including smaller app developers and data aggregators, still maintain centralized databases that could be exploited if the Court does not set a clear constitutional boundary.
Furthermore, the brief highlights the "chilling effect" such surveillance has on democratic participation. When individuals know that their presence at a church, a doctor’s office, or a political rally can be logged and scrutinized by the government without individualized suspicion, they may be less likely to exercise their First Amendment rights.
Conclusion: The Path Forward
As the Supreme Court prepares to hear oral arguments in Chatrie v. United States, the legal community and the public are watching closely. The case represents a junction between 18th-century constitutional values and 21st-century technological capabilities. The coalition of the EFF, ACLU, and Georgetown Law has made its position clear: the Fourth Amendment was designed precisely to prevent the government from casting such broad nets into the private lives of its citizens.
The ruling, expected by the end of the current term, will likely serve as a landmark decision, determining whether the "digital version of exploratory rummaging" will be permitted to continue or if the Court will reassert the necessity of individualized suspicion in the age of the smartphone. For now, the privacy of millions of Americans remains at the center of a high-stakes judicial debate over where the geofence of the law should be drawn.
