This week, in the case of Byrd v. United States, the Supreme Court ruled unanimously that a person driving a rental car has the right to privacy—that is, not to have the car searched without probable cause—even if he’s not listed on the rental contract. It’s an interesting case, especially for law students, but not earth-shattering.

But the short concurring opinion by Justice Thomas, which Justice Gorsuch joined, is a terrifying warning to anyone who cares about privacy in the age of digital surveillance.

“I have serious doubts about the ‘reasonable expectation of privacy’ test,” Justice Thomas began. At which point my eyes popped out of my head.

For more than half a century, the “reasonable expectation of privacy” has been a bedrock of Fourth Amendment law in the United States. It is what keeps us safe from arbitrary government searches in our cars, in schools, and everywhere else outside the home. It is the doctrine whose boundaries are continually tested in the world of Big Data. And it is apparently a principle doubted by two justices of the Supreme Court.

To be sure, the words “reasonable expectation of privacy” do not appear in the Constitution, which is what irks “originalists” like Gorsuch and Thomas. Rather, the Fourth Amendment states that “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated.”

That phrase covered the field in 1791. At the time, there were far fewer ways in which governmental searches might otherwise take place, particularly if you were the kind of propertied white male the text had in mind. And the Framers were clearly reacting against British army’s use of the “general warrant” to search people’s homes without any specific cause.

Well, times have changed. A crucial case this term, for example, is Carpenter v. United States. There, the question is whether the government needs a warrant to obtain a person’s location data from cellphone-tower records. It’s a close case, and it could go either way. But however it turns out, the “reasonable expectation of privacy” will be the standard the court uses—not some imaginary world in which the Founders knew about cellphones.

And so it has been for 50 years, since Katz v. United States, in 1957. Courts have determined that people have a reasonable (i.e. objective, rather than subjective) expectation of privacy exists not just in one’s person and property, but also in cars (to a more limited extent), hotel rooms, phone booths (that was the question in Katz), and phone records, but not garbage left out for collection, public documents one has signed (for obtaining a handwriting sample), or prison cells.

And, this week, to rental cars a person is driving even if they’re not listed on the rental agreement.

The Katz standard is not perfect. It requires the court to decide what society deems to be reasonable—“understandings that are recognized and permitted by society,” in the words of one case. That’s a moving target and a better subject for sociologists than jurists. Katz also rejects, but still mostly maintains, the general understanding that a “search” is about a physical intrusion into a private space. It’s a messy test.

But Justice Thomas’ alternative is far more problematic. Returning to the text of the Fourth Amendment, he writes, “The issue, then, is whether Byrd can prove that the rental car was his effect. That issue seems to turn on at least three threshold questions. First, what kind of property interest do individuals need before something can be considered “their... effec[t]” under the original meaning of the Fourth Amendment? Second, what body of law determines whether that property interest is present—modern state law, the common law of 1791, or something else? Third, is the unauthorized use of a rental car illegal or otherwise wrongful under the relevant law [and does it] affect the Fourth Amendment analysis?”

This half century of judicial time travel would erase privacy rights as we know them today. It’s hard to see how one’s cellphone records, for example, count as a personal effect (i.e. personal property). Or one’s web browser history, as tracked by an internet service provider. Or digital records of any kind, for that matter, unless they include a specific property interest.

Originalism is one thing, but limiting the Constitution to property rights cognizable in the days of the horse and carriage is another. As in many other areas of Justice Thomas’ jurisprudence—civil rights chief among them—his principles would create a majoritarian republic that looks nothing like American democracy today.

Nor is Justice Thomas’ “originalism” at all consistent. The same day he railed against the “reasonable expectation of privacy,” he joined the court in expanding the doctrine of “anti-commandeering,” which is also not found in the Constitution.

“ Originalism is one thing, but limiting the Constitution to property rights cognizable in the days of the horse & carriage is another. ”

Now, Justice Thomas has been writing crazy things for a long time. In the abortion case of Whole Women’s Health, he said that since the time of FDR, the Supreme Court’s constitutional jurisprudence is an “unworkable morass of special exceptions and arbitrary applications.”

And dissenting from the landmark same-sex marriage case, Obergefell v. Hodges, he wrote that state benefits like marriage have nothing to do with dignity, stating that “slaves did not lose their dignity (any more than they lost their humanity) because the government allowed them to be enslaved. And those denied governmental benefits certainly do not lose their dignity because the government denies them those benefits.”

That is, to put it mildly, an idiosyncratic view.

What’s different is that now, there are, in effect, two Justice Thomases, due to the addition of Justice Gorsuch to the court, which, of course, was the result of unprecedented and democracy-shattering malfeasance on the part of Senate Republicans who refused to even consider the nomination of Merrick Garland.

One weird, quirky justice is an outlier. Two begins to look like a constituency.

Nor is this the first time that Justices Gorsuch and Thomas have together tacked to the right of the court’s conservative members. In a case about providing government funding to a church playground, the conservative majority held that such funding was not an unconstitutional support of a church, since it was offered to all playgrounds. Gorsuch wrote (and Thomas joined) that it was support of a church, and that was just fine.

In another case last year, the court struck down Arkansas’ policy of listing straight couples who use artificial insemination on a child’s birth certificate, but not listing gay couples who do similarly. Justice Gorsuch (joined by Justices Thomas and Alito) wrote that “marriage” under Obergefell doesn’t mean equal marriage.

It used to be that Republicans wanted another Justice Scalia on the Supreme Court: Someone with intellectual heft who moved the mainstream to the right while respecting the basic contours of Supreme Court jurisprudence.

Increasingly, though, they now say they want another Justice Thomas: Someone who’ll throw out the baby with the bathwater, junk decades of precedent because he doesn’t like them, and radically remake the American state.

In Justice Gorsuch, it seems like they’ve got one.