On June 29, 2026, in Chatrie v. United States, the Supreme Court held in a 6–3 decision that police conduct a Fourth Amendment “search” when they obtain a person’s cell phone location data through a geofence warrant, notwithstanding the third-party doctrine.1 Writing for five of the justices in the majority, Justice Elena Kagan concluded that “[a]n individual has a reasonable expectation of privacy in records about his cell phone’s location” and that the police “intrude on that constitutionally protected interest when they demand the information—even though for only a limited time, and from a third-party tech company.”2
This Client Alert (1) summarizes the majority opinion and the separate writings, including the division on the Court over how to analyze Fourth Amendment claims; (2) explains why the decision is a direct extension of Carpenter v. United States and Riley v. California; and (3) highlights the forward-looking questions the decision raises—including what other digital information is now likely protected, how categorical that protection is and whether the warrant at issue will ultimately be upheld. For background on geofence warrants and the lower-court decisions that preceded this one, see our prior Client Alert “The Impact and Future of the Fifth Circuit’s New Hard-Line Stance on Geofence Warrants.”
The Court’s Decision
A geofence warrant is a tool that lets investigators work backward from a crime scene to a suspect. Rather than start with a known suspect, the police draw “a ‘geofence’—a virtual perimeter—around the crime scene” and obtain a warrant compelling a technology company to turn over data about all the cell phones present in that area over a set period of time.3 Because these warrants invert the usual sequence of an investigation, they are often called “reverse warrants.”4
The data at issue in Chatrie was Google’s “Location History,” which the Court described as “a time-stamped record of every place a cell phone has been.”5 When enabled, Location History logs a phone’s position “[e]very two minutes or so,” drawing on Wi-Fi, Bluetooth, cell tower sites, GPS, and IP address information to fix the phone’s location to within roughly 20 meters and even to estimate which floor of a building the phone is on.6 The case arose from the 2019 robbery of a credit union in Midlothian, Virginia. Investigators obtained a geofence warrant directed to Google for a 150-meter radius around the credit union, and through a complex three-step process described in the warrant application, narrowed the universe of users and ultimately identified suspects.
At step one of that process, Google produced “anonymized location data for all cell phones within the geofence in the hour between 4:20 and 5:20 p.m. (30 minutes before to 30 minutes after the robbery).”7 At step two, police officers attempted to narrow the list of cell phones by comparing time-stamped location data for each device against “the known time and location information that is specific to this crime.”8 Google then provided additional anonymized data: “cell-phone locations both inside and outside the geofence during a two hour period (so now from 3:50 to 5:50 p.m.).”9 Finally, at step three, the police further winnowed the list by comparing that information against crime-specific information, and Google “turn[ed] over identifying information for each user on the final list, including his name and phone number.”10 In “executing steps two and three, law enforcement initially sought unbounded data and account information from all 19 devices identified at step one.”11 “[O]nly because Google insisted” on a narrower request, law enforcement “eventually settled on requesting data from nine devices at step two.”12 Google ultimately produced identifying information for three users—one of whom was Okello Chatrie, who was later charged with the robbery.13
The Court set as a backdrop for its analysis the recurring challenge of “adhering to” settled Fourth Amendment principles “in the face of new technologies,” emphasizing that “no government official should have free access to the most closely kept aspects of [Americans’] lives.”14
Applying those Fourth Amendment principles to the specific technology at issue, the Court held that obtaining Location History data from Google was a search. To reach that conclusion, the Court applied the familiar Fourth Amendment framework from Katz v. United States15: that a search occurs when the government intrudes on an “expectation of privacy” that “society is prepared to recognize as ‘reasonable.’”16
Within that framework, the Court’s reasoning largely began and ended with Carpenter v. United States, which held in 2018 that accessing seven days of a user’s cell-site location information (CSLI) is a Fourth Amendment search because it “provides an intimate window into a person’s life.”17 “Everything Carpenter relied on” to treat access to CSLI as a search, the majority reasoned, “applies as well or better” to Location History—including because Location History is far more precise than CSLI and records a person’s whereabouts nearly seven times as often as CSLI, “for a daily average of 720” such recordings.18
The Chatrie majority also emphasized that Location History records are more the user’s own than are CSLI records. Location History records “resemble[] other private materials—think of emails, documents, photographs, or calendars—that even if stored on Google’s servers, a user reasonably views as his own” and therefore “reasonably expects to be shielded from the ‘inquisitive eyes’ of the government.”19
The Court rejected the government’s two principal counterarguments. First, the government urged that obtaining only a brief window of location data—here, about two hours—is not a search. The Court disagreed, explaining that “[w]here the Fourth Amendment applies, it applies—regardless of ‘the quality or quantity of information’ the government obtains” and that “[w]hether something is a search does not depend on what it finds.”20
Second, the government invoked the third-party doctrine, under which a person may lose their expectation of privacy in information voluntarily conveyed to another.21 The Court held that doctrine no more applies to Location History than it did to CSLI in Carpenter. As in that case, the Court saw “a world of difference” between the “limited types of personal information” at issue in the doctrine’s foundational decisions—the canceled checks and deposit slips in United States v. Miller, the dialed telephone numbers in Smith v. Maryland—and the comprehensive account of a person’s movements that location data supplies.22 And it refused to make the application of the Fourth Amendment turn on how many users enable a feature or on the fact that they must switch it on, rejecting an “app-by-app, feature-by-feature method of granting Fourth Amendment protection” as a misunderstanding of how people actually use their phones.23 A person, in short, “is not to be viewed as sharing private information with third parties—which then can be freely passed on to the government—just by doing the ordinary things cell-phone users do.”24
Having held that a search occurred, the Court declined to decide whether this search and, in particular, the complex multistep narrowing procedure used to identify the defendant were reasonable and satisfied the requirements of particularity and probable cause, leaving those thorny questions for the Fourth Circuit on remand.25
Looking Ahead
What Else Is Protected?
The Court framed its holding narrowly, in terms of “location information.”26 But its reasoning is not so confined. Although stored content already carries its own statutory warrant requirement,27 the majority’s opinion suggests the Constitution independently requires that result for other cloud-stored material. By grounding protection in the principle that materials a user “reasonably views as his own” remain private even when stored on a provider’s servers—and by naming “emails, documents, photographs, or calendars” as examples—the opinion lays the analytic groundwork for affording constitutional protection to a broad range of cloud-stored personal data.28 Justice Samuel Alito’s dissent warns that the rationale could reach as far as “a person’s Amazon purchase history” and his “Google search history or Venmo transaction log.”29] To be clear, these examples describe where the majority’s reasoning might lead, not where the law stands today: Justice Alito posits that this kind of information “fall[s] squarely within the third-party doctrine” and that the majority’s holding “does not ostensibly disturb that fact.”30 As a predictive matter, however, the more a user treats material entrusted to a provider as his own or the more that material reveals the personal activities of the user, the more likely a court is to find the user maintains a reasonable expectation of privacy in the material.
How Robust Is the Protection—Categorical or Fact-Bound?
The decision reflects a categorical rather than fact-dependent approach to Fourth Amendment analysis. The Court held that the Fourth Amendment applies “regardless of ‘the quality or quantity of information’ the government obtains” and that “[w]hether something is a search does not depend on what it finds.”31 It similarly declined the government’s invitation to recognize a durational “grace period,” reasoning that any such line would be arbitrary and unworkable.32 And it reaffirmed that “we have never understood Fourth Amendment protections as kicking in only once an intrusion ‘goes too far.’”33 What controls is the core nature of the information the government seeks, not the duration or comprehensiveness of any particular request. What remains fact-dependent is whether a person’s “expectation of privacy” in a given type of data “is one that society is prepared to recognize as reasonable.”34 As noted, how far the decision’s logic will extend in the context of other categories of cloud-stored data is an open question.
Other Open Questions
Several significant Fourth Amendment questions remain unresolved after Chatrie. It is clear the third-party doctrine survives—Smith and Miller are still good law—but its domain continues to shrink in the context of modern technology. And the Court left to lower courts the thorny issues of the particularity and probable-cause requirements that govern geofence warrants in particular and reverse warrants more broadly.
The Chatrie Concurrences, Dissents, and Divide on the Court
Justice Ketanji Brown Jackson, joined by Justice Sonia Sotomayor, agreed that a search occurred but would have held it unreasonable as well.35 In her view, the later stages of the geofence process lacked probable cause and particularity. The warrant, she wrote, gave officers a “‘roving commission’” to demand more data without a neutral magistrate’s approval, and the officers pared back their requests “only because Google insisted on it.”36 Justice Neil Gorsuch, meanwhile, concurred only in the judgment. He would abandon the Katz reasonable-expectation-of-privacy test, which in his view “has no basis in the Constitution’s text or history,” and instead apply a property-based test that asks whether the government searched a person’s “papers or effects.”37
Justice Alito, joined in part by Justices Clarence Thomas and Amy Coney Barrett, dissented. He would not have reached the merits, and he read neither traditional Fourth Amendment principles nor the third-party doctrine of Smith and Miller to treat the geofence procedure as a search.38 The majority’s rule, he warned, has no stopping point. If police need a warrant “however brief the duration, however innocuous the request, and however voluntarily” the data was disclosed, they may soon need one for a range of information that companies store, like a user’s Amazon purchases.39 Justice Barrett also separately dissented, briefly writing that she had “no quarrel with Carpenter” but agreed that Chatrie “had no reasonable expectation of privacy in data about his public movements that he voluntarily disclosed to Google.”40
The separate writings reveal a three-way split over how the Fourth Amendment applies to new technology. The five justices who joined the majority would keep the Katz test and use it to protect information that users reasonably consider their own, even when a third party holds it. Justice Gorsuch would discard Katz and the third-party doctrine in favor of a property-based inquiry, though one that would still have protected Chatrie’s Location History.41 And Justice Alito, joined in part by Justices Thomas and Barrett, would preserve a broad third-party doctrine that leaves much digital surveillance outside the warrant requirement. Ultimately, the majority opinion suggests that a more privacy-friendly view of what counts as private information, and a correspondingly narrower third-party doctrine, will shape the Court’s digital-privacy cases going forward.
WilmerHale Can Help
WilmerHale has been at the forefront of these issues, having long advised technology companies on responding to law enforcement demands for user data, including reverse warrants. And it authored an amicus brief (in support of neither party) in Chatrie. We are analyzing the decision’s implications and are available to counsel clients on the questions it raises, including:
- Reverse-warrant compliance. Assessing and refining policies and protocols for responding to geofence, reverse-keyword and other reverse warrants in light of the Court’s decision, including the particularity and probable-cause standards courts are likely to apply for such warrants going forward.
- Data storage and product design. Evaluating how data collection and storage practices, including encryption, bear on Fourth Amendment exposure and on a company’s ability to respond to legal process.
- Engagement with law enforcement. Advising on communications with law enforcement authorities as they adjust their practices to the decision and interacting directly with law enforcement in response to legal process on behalf of providers.
- User communications and privacy positioning. Helping companies explain their practices to users in a way that reflects both their legal obligations and their commitments to privacy.
