I had a great conversation with Professors Andrew Ferguson (GW Law) and Paul Ohm (Georgetown Law) about Chatrie v. United States (U.S. June 29, 2026).
Quick takes from the conversation:
- Is Chatrie the most important Fourth Amendment case this century? Yes.
- Does Chatrie dramatically curtail the third party doctrine? Yes.
- Does Chatrie answer whether geofence warrants violate the Fourth Amendment? No.
- Will Chatrie require a big rethink to whether many forms of government surveillance and data gathering require a warrant? Yes.
- Can the government buy personal data from data brokers after Chatrie? Maybe.
- Are warrants enough protection against government surveillance in the digital age? No.
Chatrie v. United States
There were two questions before the Court: (1) Did the Fourth Amendment apply at all? The government argued there was no reasonable expectation of privacy in the data. (2) Did the geofence warrant violate the second clause of the Fourth Amendment, which requires particularized warrants and prohibits dragnet searches.
The Court punted on the second question but it emphatically addressed the first. The Court held there is a reasonable expectation of privacy in a person’s location data, even though it was shared with a third party.
My Take on Chatrie
- What? The type of data being gathered, such as sensitive data or data revealing a person’s private life.
- How? The method of surveillance being used regardless of whether it turns up anything because the Fourth Amendment applies “regardless of the quality or quantity of information the government obtains.”
- How Much? Gathering an “exhaustive chronicle” of data about a person’s life triggers the Fourth Amendment.
I also find in Chatrie the following principles:
- Even short-term surveillance counts. The length of time of surveillance isn’t dispositive. Even short-term monitoring can be a search if it turns up a “wealth of detail” about a person.
- Intrusive activities count, even if no data is found. “[W]e have never understood Fourth Amendment protections as kicking in only once and intrusion ‘goes too far.’” The Court also states: “Whether something is a search does not depend on what it finds.”
- People can have an expectation of privacy in public. Surveillance of one’s location, even in public, still can violate a reasonable expectation of privacy.
- People have a reasonable expectation of privacy in records stored for their own purposes with third parties. Data a “user reasonably views as his own” is protected by the Fourth Amendment, “even if stored on Google’s servers.”
- Consent to share data with third parties doesn’t eliminate a reasonable expectation of privacy. People need to share data as an “indispensable part of daily life” and this sharing doesn’t waive Fourth Amendment protections.
Many of these principles are at odds with earlier cases such as Smith, Miller, and Knotts. The Court is reluctant to overrule them, but after Chatrie many cases or parts thereof are likely no longer valid (or are constrained to their facts or limited to a particular point in history before modern technology).
Background: The Road to Chatrie
- “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”
The Reasonable Expectation of Privacy Test
- Katz v. United States, 389 U.S. 347 (1967) – birth of the current test to determine Fourth Amendment applicability—the reasonable expectation of privacy test: (1) a person must exhibit an “actual (subjective) expectation of privacy,” and (2) “the expectation [must] be one that society is prepared to recognize as ‘reasonable.’”
Third Party Doctrine Cases
- Smith v. Maryland, 442 U.S. 735 (1979) – no reasonable expectation of privacy exists in the numbers that a person dials when the police record them with a pen register because people “know that they must convey numerical information to the phone company.”
- United States v. Miller, 425 U.S. 435 (1976) – no reasonable expectation of privacy in financial records maintained by one’s bank because “the Fourth Amendment does not prohibit the obtaining of information revealed to a third party and conveyed by him to Government authorities.”
No Privacy in Public Cases
- Florida v. Riley, 488 U.S. 445 (1989) – flying a helicopter over a person’s property to peer into missing roof panels of a greenhouse didn’t trigger a reasonable expectation of privacy because it was visible from a vantage point accessible to the public.
- United States v. Knotts, 460 U.S. 276 (1983) – using a tracking device that monitors a person’s movements in public doesn’t trigger a reasonable expectation of privacy because the activity is in public.
The Final Footsteps to Chatrie
- United States v. Jones, 565 U.S. 400 (2012) – installing a GPS device on a car is a search because it involves a trespass on a person’s property. Concurring opinions suggested that the GPS tracking violates a reasonable expectation of privacy.
- Riley v. California, 573 U.S. 373 (2014) – searching a cell phone seized during an arrets requires a warrant because the data on cellphones is far more extensive than other physical things an arrestee possesses. Cell phones contain “many distinct types of information—an address, a note, a prescription, a bank statement, a video—that reveal much more in combination than any isolated record” and “[t]he sum of an individual’s private life can be reconstructed through a thousand photographs labeled with dates, locations, and descriptions; the same cannot be said of a photograph or two of loved ones tucked into a wallet.”
- Carpenter v. United States, 585 U.S. 296 (2018) – an individual has a reasonable expectation of privacy when the government “accesses historical cell phone records that provide a comprehensive chronicle of the user’s past movements.”
After Carpenter: Shyness and Silence
The Court took an 8-year hiatus from addressing these issues, an unusually long gap for the Court which generally heard took Fourth Amendment cases quite frequently.
The Court was very skittish and afraid in Carpenter. Note this key paragraph:
Our decision today is a narrow one. We do not express a view on matters not before us: real-time CSLI or “tower dumps” (a download of information on all the devices that connected to a particular cell site during a particular interval). We do not disturb the application of Smith and Miller or call into question conventional surveillance techniques and tools, such as security cameras. Nor do we address other business records that might incidentally reveal location information. Further, our opinion does not consider other collection techniques involving foreign affairs or national security. As Justice Frankfurter noted when considering new innovations in airplanes and radios, the Court must tread carefully in such cases, to ensure that we do not “embarrass the future.”
What makes Chatrie so impactful is that finally, after all these years, the Court has become much bolder and isn’t whimpering anymore.
Articles About Chatrie
- For Ferguson, Chatrie affirms that “‘digital is different’ when it comes to the Fourth Amendment.” Chatrie’s “remarkable conclusion” that “short-term location tracking violates a reasonable expectation of privacy,” which “does away with durational line drawing” that played a central role in Carpenter and in Jones.
- In Chatrie, “the Supreme Court did not formally overrule the third-party doctrine. Instead, they distinguished it to the point of irrelevance in the digital age.” “Location data and other indispensable data now stand outside the third-party doctrine.” This is because Chatrie carved out “‘indispensible’ technologies, like smartphone apps and services, as being something outside the third-party doctrine.”
- “Chatrie’s expanded reading of digital expectations of privacy (and property) will have wide-ranging application, limiting the government’s power to rummage through our digital lives.”
Christopher Slobogin, The Implications of Chatrie: Are the Walls Tumbling Down? (2026)
- Chatrie “spell[s] doom for most applications of the third party doctrine.”
- “If the third party doctrine only applies when customers completely understand and agree to all the ways a company uses their information, then it is irrelevant in many other third party cases.”
- “Chatrie signals that the conceit that people ‘voluntarily’ choose to surrender their information to third party institutions that any functioning member of society must patronize is no longer accepted by the Court.”
Orin S. Kerr, The Fourth Amendment After Chatrie, 102 Notre Dame L. Rev. (forthcoming 2027)
- “Chatrie is now the most important Fourth Amendment case on new technology, and it throws into question a wide range of existing surveillance practices.”
- “Chatrie is not just an application of Carpenter. . . . At the broadest level, Chatrie changes Carpenter’s underlying rationale of protection from the balance of power to the need to protect private information, paired with a broad understanding of what counts as private information. . . . This is a new case resting on new principles, and that should cause courts to rethink old approaches.”
- Kerr offers three potential readings of Chatrie: “At times, it sounds like an opinion on the special need for Fourth Amendment protections in location records. At other times, it reads as an opinion on the special privacy rules for records generated by cell phones. And in parts, it reads as an opinion on the need for Fourth Amendment protection in all private-seeming records created or held by others. These three readings have different implications. Each suggests a different set of applications to other technologies, and each suggests a different set of questions that courts will confront if they follow that path.”
- “To say that the Fourth Amendment should protect privacy against whatever threat to privacy exists, as Chatrie does, does not answer what ultimate standard the Fourth Amendment protection is aimed at addressing. Yes, courts should protect privacy. But how far should they protect privacy? How would we know if the Fourth Amendment is protecting privacy too little or too much?”
Matthew Tokson, The Chatrie Test and the Future of the Fourth Amendment, 101 Notre Dame L. Rev. (forthcoming 2027)
- “Chatrie is an enormous victory for digital privacy. It offers robust protections for people’s location data. Its logic extends far beyond its facts, potentially applying to any aspect of modern life, from the cellphone to the internet to non-digital activity like walking or driving.”
- “Chatrie confirms that the Supreme Court is pursuing a privacy-centered Fourth Amendment jurisprudence, one that is flexible enough to protect sensitive personal information in the modern era.”
- “Rather than adopting the rules of pre-internet surveillance or cautiously expanding existing law, the Court has repeatedly departed from existing paradigms in order to protect privacy against new forms of surveillance. It has increasingly focused on the appropriate balance between privacy and law enforcement interests, and less on adjusting old laws while hewing closely to them.”
- “[I]n general, the era of the third-party doctrine has ended,” and “the third-party doctrine will likely be confined to a handful of old cases decided prior to the digital era and preserved via stare decisis.”
Daniel J. Solove, Is the Fourth Amendment Third Party Doctrine Dead? Thoughts on Chatrie v. United States
- “The Court appears to be on the verge of scuttling the third party doctrine. Instead of killing it, the Court is just shrinking the zone to a point where the doctrine will be very narrow and rarely applicable.”
* * * *
Daniel J. Solove is the Bernard Professor of Intellectual Property and Technology Law at the George Washington University Law School. He is the founder of TeachPrivacy, a company that provides workforce privacy, cybersecurity security, and AI training to companies and organizations around the world. He is the author of 10+ books and 100+ articles.
You can follow his events, writings, training, cartoons, and resources by subscribing to his free weekly newsletter.
Subscribe to Solove’s Free Substack
A supplement to Solove’s regular newsletter with more in-depth discussions
