The Supreme Court Hears the Biggest Fourth Amendment Case in a Decade Today — and the Right Answer Isn't Close

Today, April 27, 2026, the Supreme Court hears oral argument in Chatrie v. United States¹, and I think it is the most important Fourth Amendment case since Carpenter v. United States in 2018. The question sounds technical: did a geofence warrant used to identify a Virginia bank robber violate the Constitution? The answer will determine whether law enforcement can compel tech companies to search the digital movements of hundreds of millions of people to generate suspects where none previously existed.

Let me explain what actually happened. In May 2019, someone robbed a credit union in Midlothian, Virginia. Police had surveillance footage and witnesses but couldn't identify the robber. So Detective Joshua Hylton obtained a warrant directing Google to search its Sensorvault database — which at its peak held location records for roughly 592 million accounts⁴ — and return data on every device present within 150 meters of the bank during the hour surrounding the robbery. Google returned 19 anonymized accounts and 209 location data points². Detective Hylton then narrowed the list, asked Google to de-anonymize three accounts, and identified Okello Chatrie. Police found nearly $100,000 in cash and robbery demand notes at his home. He confessed and was sentenced to nearly 12 years⁹.

The geofence warrant worked. That's the hardest thing for the constitutional argument against it. But I think that argument is clearly right, and I want to walk through why.

The inversion problem. The Fourth Amendment requires warrants to "particularly describ[e] the place to be searched, and the persons or things to be seized." This requirement exists because the Founders had direct, bitter experience with general warrants and writs of assistance — instruments that let British officers search anyone, anywhere, on suspicion of anything. A geofence warrant flips the constitutional logic: instead of identifying a suspect and then searching for evidence, it searches everyone to find a suspect⁷. As Chatrie's lawyer Adam Unikowsky told the Court, "The Fourth Amendment was born of the Founders' revulsion for general warrants and writs of assistance — instruments that allowed the government to search first and develop suspicions later."

The government's best response is that geofence warrants do specify particulars: GPS coordinates, a time window, and a type of data. And Google's three-step disclosure process — anonymized returns first, then narrowing, then de-anonymization — adds layers of protection. The Solicitor General's brief¹⁴ argues that "the Fourth Amendment's particularity requirement focuses on the information the government itself gets to view."

I think this argument has a fatal flaw. The three-step process is Google's corporate policy, not a constitutional constraint embedded in the warrant. In Chatrie's own case, this mattered: Detective Hylton initially asked Google for de-anonymized data on all 19 accounts at once¹⁰, and Google refused because he hadn't followed the sequential narrowing process. Hylton then modified his request. But the warrant itself didn't require narrowing — Google enforced it voluntarily. If Google had complied with Hylton's original request, nothing in the warrant would have prevented full de-anonymization of every person near that bank. The Fourth Amendment's protections cannot depend on whether a private company happens to push back.

The circuit split tells the story. The lower courts are hopelessly divided. The Fourth Circuit held in a panel decision that accessing two hours of location data wasn't even a Fourth Amendment "search"⁵ because Chatrie voluntarily shared his data with Google. The Fifth Circuit, ruling weeks later in United States v. Smith, reached the opposite conclusion: geofence warrants are "categorically prohibited by the Fourth Amendment"⁶ because they force Google to search all 592 million accounts to find a handful of matches. When the full Fourth Circuit reheard Chatrie en banc, 15 judges produced a one-sentence opinion accompanied by eight concurrences and one dissent spanning over 100 pages³. The court split 7-7 on whether a search even occurred. That's not a legal question in a healthy state of resolution.

The Texas Court of Criminal Appeals muddied things further. In Wells v. State (2025), it found geofence warrants constitutional — meaning geofence warrants are now presumptively legal in Texas state courts but unconstitutional in Texas federal courts³. That's an untenable situation.

The consent argument is weaker than it looks. The government leans heavily on the third-party doctrine: Chatrie opted in to Google's Location History, so he "assumed the risk" that Google would share his data. The Fourth Circuit's panel decision relied on the fact that Location History "is off by default and can be enabled only by a user's affirmative act."⁵ This sounds reasonable in the abstract. In practice, it's quite thin. An internal Google email, surfaced in Arizona litigation, acknowledged that the Location History interface "feels like it is designed to make [opting out] possible" but is "difficult enough that people won't figure it out"⁴. The Fifth Circuit observed pointedly that "the fact that approximately 592 million people have 'opted in' to comprehensive tracking of their location itself calls into question the 'voluntary' nature of this process." Google's own Supreme Court amicus brief now argues that geofence warrants should be treated as searches² and that the third-party doctrine shouldn't apply "simply because users disclose limited information to a service provider." When the company whose data is at issue tells the Court its users didn't meaningfully consent, that's a significant data point.

More importantly, Carpenter already addressed this. Chief Justice Roberts wrote in 2018 that the third-party doctrine doesn't mechanically apply to comprehensive digital location records, because people don't make meaningful, transactional choices about the data their phones generate. GPS-precision records updated every two minutes — which is what Google's Sensorvault captured, according to district court findings¹¹ — are more revealing than the cell-site location data Carpenter protected, not less.

The strongest counterargument, and why it doesn't hold. The most sophisticated defense of geofence warrants comes from legal scholars like Orin Kerr, who filed an amicus brief¹² arguing that a properly drawn geofence warrant can satisfy the Fourth Amendment if it's narrow enough in time and space. Kerr has a point that the Fifth Circuit's categorical ban may prove too broad — if searching any large database is unconstitutional regardless of the warrant's scope, that logic could threaten wiretaps, pen registers, and even conventional subpoenas. The Harvard Law Review made a similar observation, calling the Fourth-Fifth Circuit split the "inevitable consequence of existing Fourth Amendment doctrine being a poor fit for big technology⁴."

But I think the right answer is more specific than a categorical ban and more protective than the Fourth Circuit's approach. The core constitutional problem isn't the size of Google's database. It's that the warrant authorizes the government to compel a search of constitutionally protected location records belonging to people against whom there is zero individualized suspicion. A bank subpoena for one customer's records requires a database query touching millions of rows, yes, but the warrant authorizes access to one customer's records. A geofence warrant authorizes access to every record matching a geography. The authorization itself is the defect.

What makes this case matter beyond geofences. Google announced in 2023 that it would move Location History data to on-device storage, and as of July 2025, all previously server-stored data was deleted or migrated². Google can no longer respond to geofence warrants based on Location History. So is Chatrie moot? Not remotely. The Brennan Center's amicus brief⁷ warns that a ruling upholding geofence warrants would "open the door to a variety of 'reverse search' warrants" — keyword warrants asking who searched a victim's name, AI chatbot prompt warrants, video surveillance dragnet searches. Whatever the Court says about the constitutionality of searching a geographic database applies by analogy to every other reverse-search tool law enforcement will develop. This is why 29 amicus briefs were filed, from the ACLU to X Corporation to the Cato Institute.

I expect the Court to hold that geofence warrants constitute a search under the Fourth Amendment. The harder question is whether the Court will declare them categorically unconstitutional or articulate a framework under which narrowly drawn geofence warrants might survive. My prediction: a majority opinion, probably written by Roberts, finding that the warrant in Chatrie was unconstitutional but declining to categorically ban all geofence warrants. The opinion will establish that (1) GPS-precision location data is protected under Carpenter regardless of the third-party doctrine, (2) the particularity requirement constrains the warrant's authorization, not just what the government ultimately receives, and (3) each step in the sequential process requires independent judicial authorization. That framework would effectively kill the warrant in Chatrie while leaving a theoretical path for extremely narrow geofence warrants in the future — a path that, in practice, would be nearly impossible to walk. Watch for where Justice Kavanaugh lands. He and Barrett are the wild cards; Roberts needs at least one of them to extend Carpenter's logic rather than retreating to the mechanical third-party doctrine that three current dissenters in Carpenter — Thomas, Alito, and Gorsuch — preferred⁸.