In May 2019, a man robbed a credit union in Virginia, made off with $195,000, and vanished. Witnesses noticed only one odd detail: as he approached the bank, he appeared to be talking on his cell phone. Weeks later, with the trail cold, police tried something unimaginable a generation ago. They asked a magistrate for a geofence warrant—an order compelling Google to search the location histories of over 500 million users to identify every cell phone that had been near the credit union around the time of the crime and, after winnowing down the list a couple times, reveal the identities of the cell phones’ owners. At the end of the three-step process, Google gave police three names. One was Okello Chatrie.

　　This past Monday, in Chatrie v. United States, the Supreme Court decided that process was a Fourth Amendment “search” and remanded the case to the Fourth Circuit to determine whether the broad geofence warrant was adequate, or whether the Constitution requires more. But the real story is how the Court reached its holding—and why a lone concurrence may, in the long run, matter more than the majority opinion.

　　What Was at Stake

　　The Fourth Amendment guarantees the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures. For most of American history, that text did work on its own terms. In the common law, privacy was protected—robustly—but not as a freestanding right. It was the by-product of other common-law rights. If a stranger opened your mail, for example, that was a trespass against your papers. If a housekeeper rifled through your private papers, it could be both a trespass and a breach of contract. And so on.

　　That changed after 1890, when a young lawyer named Louis Brandeis—later a Supreme Court Justice—co-authored a Harvard Law Review article proposing a new, freestanding right to privacy, which he called the right to be let alone. The amorphous new “right,” which was intended to be upheld only when it survived a balancing test pitting it against the “public interest,” first became part of tort law before being welcomed into Fourth Amendment doctrine. Legal protection for privacy has suffered ever since.

　　The worst setback was in 1967, in Katz v. United States. Fun fact: The famous test that emerged from Katz—the one every law student can recite, asking whether a person had an expectation of privacy that society is prepared to recognize as reasonable—appears nowhere in the majority opinion. It comes from Justice Harlans solo concurrence. The Court adopted it as the test for a Fourth Amendment search only afterward, but it has endured for nearly sixty years.

　　The trouble with Harlans test is that it converted what had been a question of principle into a matter of opinion. Whether the amendment protects you no longer turned on whether you owned or otherwise had a protected right to the thing searched, but on what judges supposed society was prepared to tolerate. And once legal protection for privacy became a matter of a judge weighing societys expectations against those of the individual, government was eager to set the terms of comparison. Not surprisingly, it wasn’t long before government’s own alleged needs—for security, for information, for efficiency—kept winning. In 1976, the Court held in United States v. Miller that you have no Fourth Amendment interest in your bank records, because you voluntarily handed them to the bank. Three years later, in Smith v. Maryland, it said the same of the phone numbers you dial. From these cases emerged the supersized third-party doctrine: share information with anyone, even on delimited terms, and the government may obtain it without a warrant. Your contract with a service provider, which the common law would have treated as binding and protective of your privacy, dissolved into whatever judges imagined “society” thought it was worth—usually not much.

　　The Chatrie Majoritys Answer

　　Enter Chatrie. Its immediate predecessor was Carpenter v. United States (2018), in which the Court held that the government needs a warrant to obtain a week or more of cell-phone location records from a carrier. Writing for a five-justice majority, Justice Kagan treated Chatrie as a near-mechanical application of Carpenter. If anything, she reasoned, Googles Location History is more revealing than the data in Carpenter: it pinpoints a phone within about twenty meters rather than within a sector of up to several square miles, logs a position every couple of minutes, and can even tell which floor of a building youre on. Everything that made Carpenter a search, she concluded, applies as well or better here. The third-party doctrine again failed to save the government, because this information is not truly shared in any ordinary sense—it is simply the inevitable byproduct of carrying a modern phone.

　　If a warrant is now required for location data, where does the logic stop? What about your Amazon purchase history, your Google searches, your Venmo ledger, your Apple Pay record?

　　So the Court held that a search occurred and remanded the case for the Fourth Circuit to determine, in the first instance, whether the unusual three-step geofence warrant satisfied the Fourth Amendments demands of probable cause and particularity at each stage. A majority holding that a search occurred was already more than many expected out of Chatrie. But notice what the majority would not do. While it calls the records his freely—and even likens them to Chatries own emails and photos—it refuses to let that ownership decide anything. The Katz test remains: a search occurred because it violated a “legitimate expectation of privacy.” The possessives do the persuading; the principle of private ownership does not. The Court helped itself to the principles of property and contract while denying them any doctrinal standing.

　　Gorsuch Goes Where the Majority Wouldnt

　　Justice Gorsuch, concurring only in the judgment, pointed out the elephant in the room. He would skip the expectations test entirely and ask the questions the Fourth Amendments text actually poses: Is Location History one of Chatries effects? And did the government search it?

　　His answers: a resounding yes to both. As to the first, Chatries agreement with Google called the data your information. Chatrie could review it, edit it, export it, delete it, and exclude everyone else from it. Those are the classic sticks in an owners bundle of sticks—including the right to exclude, which the Court, in Cedar Point Nursery v. Hassid (2021), has called the “most treasured” of them. That Google stored the data on its servers and had access to it changes nothing. As Gorsuch puts it, entrusting your effects to a third party for certain agreed purposes doesnt mean they are no longer yours. Toss your keys to a valet, ask a neighbor to mind your dog, and the property remains yours throughout.

　　And as to the second, because the data is Chatries effect, the government searched it the moment Google queried its vast database at the government’s behest. Here Gorsuch goes further than the majority. Where the Court left the precise timing of the search’s occurrence for another day, Gorsuch would hold that a search occurred at the very first step—when the government … compelled Google to rummage through its customers data. The search was complete before the police themselves saw any of the data—and of course long before Google named names.

　　Little of this is new ground for Gorsuch; whats new is the opportunity to use it. He sketched this same property approach eight years ago, dissenting in Carpenter v. United States—the bailment, the valet, the dog-sitter, all appeared there too. But the defendant in that case had argued only the expectations test, leaving Gorsuch to lament that Mr. Carpenter forfeited perhaps his most promising line of argument. So the 2018 opinion spoke in the conditional: the data “could qualify” as Carpenter’s papers or effects; his interest “might even rise to the level of a property right.” This time the argument was properly raised—Chatries brief led with it—and the hedges fall away. The data, Gorsuch now states flatly, is his effect. What was a forfeited possibility has become a decided ground.

　　His posture toward the third-party doctrine has hardened in the interval, too. In Carpenter he treated the expanded doctrine that emerged from Miller and Smith as a worthy adversary to be outflanked—methodically dismantling justifications for the expansion, yet choosing to route around the doctrine rather than call for its end. In Chatrie the doctrine’s precedential value is moldering; it’s more relic than adversary. Gorsuch dismisses it as an indefensible qualification and battered offshoot of Katz, needling the majority for giving it a quiet burial. He still stops short of moving to overrule it. But the shift is unmistakable: a doctrine he once worked carefully around, he now treats as already crumbling, with the only open question being whether the Court will be honest about the cause of its demise.

　　The Dissent Has a Point

　　Justice Alito, in dissent, made two arguments. The first is procedural: because the lower court had already upheld Chatries conviction on a separate good-faith ground that the majority never disturbed, nothing the Court said is likely to change the outcome of his case. The opinion, Alito charged, is therefore advisory—a constitutional pronouncement dressed up as a decision. His second argument is the one that could haunt courts for years. If a warrant is now required for location data, where does the logic stop? What about your Amazon purchase history, your Google searches, your Venmo ledger, your Apple Pay record? Each can paint a portrait of a private life every bit as intimate, and each, for now, falls within the third-party doctrine the majority left standing. (Justice Barrett dissented briefly to say she agreed with Alito’s view that the majority reached the wrong result, even though she, unlike Alito, had no issue with either Carpenter or with the Court’s decision to hear the case.)

　　Alitos line-drawing complaint is devastating against the majority. The majoritys rule asks questions with no stable, predictable answers: How much surveillance is too much? Which technologies has society come to accept? The majority rule’s application must be relitigated every time a new device, app, or media type appears. Gorsuchs framework, by contrast, asks questions applicable in predictable ways to any technology: Is this thing yours? Did the government search it? Ownership ports across technologies; expectations may not.

　　Fourth Amendment law has already witnessed a single concurring justices framework become the majoritys—that is the history of the Katz test. Gorsuchs property- and contract-based approach, which rests on a foundation laid by the late Justice Scalia in Kyllo v. United States (2001), United States v. Jones (2012), and Florida v. Jardines (2013), is following a similar path: a dissent in Carpenter eight years ago, a concurrence in the judgment this week, one seat nearer the center. It commands no majority now. Neither did Harlans, at first. The clearest, most consistent opinion in Chatrie rode sidecar. If we take history and principle as our guide, it is Gorsuch’s framework that should endure. With persistence and a bit of good fortune, it will.