Carpenter and the Property Vocabulary

Last week, the Supreme Court heard oral argument in Carpenter v. United States, which will decide whether the government may acquire — without a warrant, and without probable cause — records of a person’s movements, using cell-site location information. It was a lively argument, but I’m going to focus on Justice Gorsuch’s questions about what he called the “property-based” theory of the Fourth Amendment. I’m going to argue that property law supplies useful analogies and language (here, the idea of a bailment), even if you are not convinced that the Fourth Amendment should turn on the content of property law. First, a few words of background on the competing models of a Fourth Amendment search. The Fourth Amendment protects our right to be secure, from unreasonable “searches and seizures,” in our “persons, houses, papers, and effects.” It’s therefore very important to determine what counts as a search. For much of the Court’s history, this turned on whether the government had physically intruded into one of the listed categories. In Olmstead v. United States, for example, government agents wiretapped phone lines running to the defendant’s home, but did not physically enter onto his property, and the Court concluded that there had (thus) been no Fourth Amendment “search.” Over the course of the 1960s, the Court took a broader view, holding that some non-physical invasions by the government were searches when they invaded the defendant’s “reasonable expectations of privacy.” But as Justice Scalia explained for the Court in Florida v. Jardines, the latter-day cases were not intended to subtract from the old baseline: when the government physically intrudes on a person, house, paper, or effect, a search has undoubtedly occurred. This is sometimes called a “trespass” theory or a “property-based” theory of the Fourth Amendment. At oral argument, Justice Gorsuch returned to what he called “the property-based” approach several times. He began by asking Nate Wessler, Carpenter’s attorney, what state law would say about the location records: “Say a thief broke into T-Mobile, stole this information, and sought to make economic value of it,” he asked. “Would your client have a conversion claim, for example, under state law?” (Wessler demurred that it was “possible.”) Gorsuch returned to the question with Michael Dreeben, arguing for the United States: “Let’s say I have a property right in the conversion case I posited with your colleague,” he said. “Wouldn’t that, therefore, be a search of my paper or effect under the property-based approach?” Dreeben (after some further prompting) confessed he was not sure, because “there has never been a property right recognized in information that’s conveyed to a business of this character.” In fact, in the course of human life, it is routine to give something that belongs to you to someone else for a limited purpose, without intending to surrender your proprietary interest in it. We call this a bailment. When you go to an event and check your coat, the coat-check is a bailee: they have your property, yes, but they must return it on your demand. When you hand your car keys to a valet, you mean for him to drive it, yes, but certainly you do not mean that he can go for a joy ride or lend the car to someone else. (The Supreme Court used a very similar example just last year.) In his monograph An Essay on the Law of Bailments (originally published in the eighteenth century), William Jones observed unlike England’s “abstruse, though elegant, system of real property,” which most people could pass through life “without knowing, or caring to know,” there is almost no one who “does not every week, and almost every day,” grapple with bailments. Bailments, thought Jones, were “among the principal springs and wheels of civil society.” And it would be entirely possible to resolve Carpenter by concluding that the government had acquired information about Carpenter (his location) that he shared with his cell-phone provider in the course of a bailee-like relationship — that there were meaningful limits to the interests he surrendered. The result, in that case, should therefore not be any different than if the government had searched his coat at a coat-check. To be clear, I have no idea whether the cell-phone company was, for state-law property purposes, a bailee of Carpenter’s location information. In other words, I do not know what the positive-law model of the Fourth Amendment says about Carpenter. But the Court’s opinions, even its opinions applying the so-called property-based model, have not turned on positive law; they have turned on a series of analogies and arguments to property-law concepts that sit, so to speak, on their own bottom. For an example of what I mean, take Justice Scalia’s approach in Florida v. Jardines. In Jardines, the question was whether it was a Fourth Amendment search to take a drug-sniffing dog up to the porch of someone’s home (which, in a portion of the opinion not relevant to this discussion, the Court concluded was part of the home itself for Fourth Amendment purposes). The Court began with a general rule drawn from the law of property: “[N]o man can set his foot upon his neighbour’s close without his leave.” But that general rule was drawn from Entick v. Carrington, a 1765 case from England (one that was “undoubtedly familiar,” the Court says, to American statesmen at the time of the founding) — not the common law of Florida. The Court went on to investigate whether Jardines had given his “leave,” even implicitly, for the officers to approach—and concluded that he had not. In answering that question, the Court (again) did not look to the common law of Florida, but to (as Holmes had done nearly a century before) “the habits of the country.” A knocker on the front door is an invitation, yes—one that “permits the visitor to approach the home by the front path, knock promptly, wait briefly to be received, and then (absent invitation to linger longer) leave.” But the terms of that invitation, in the Court’s view, were set, for Fourth Amendment purposes, by Fourth Amendment law, though borrowing conceptually from the general law of property. There is something to this approach — something, in other words, to using property-law concepts without actually importing the peculiarities of each State’s positive law of property. As Justice Kagan reasoned in her Jardines concurrence, the law of property influences our “shared social expectations” about privacy. I would add to that only that it is also influenced by those social expectations. It also supplies a rich vocabulary to express the various ways in which we relate to one another in the material world — a vocabulary rich enough, for example, to have a name for the idea that we sometimes hand over something without meaning to surrender it for any purpose whatsoever. Even if one believes, like Justice Frankfurter, that it would be “unnecessary and ill-advised” to make Fourth Amendment results turn entirely on the fine-grained distinctions that are in fact drawn by property law, one might still believe that the field has something to teach us — lest we find ourselves simply reinventing old distinctions under new names.