“My Domino’s hypothetical,” as Judge Leon, of the D.C. District Court, calls it, captures several of the elements that make his decision particularly strong, and give it the potential to change the direction of the legal discussion surrounding the N.S.A.’s surveillance programs. First, and perhaps foremost, it is unencumbered by the delusion that bulk metadata collection is a practice that will only traipse on bad people. A painfully uncritical “60 Minutes” segment that ran Sunday night talked about how the N.S.A. would follow “hops” in metadata to clusters of “known pirates”; Leon sees people in New York who want pizza; he may even see himself. And he sees how one can be subject to an unwarranted invasion just by having one’s phone records put through the analytical mill, by N.S.A. analysts who enter queries “without seeking approval of a judicial officer.”

Second, there is a practical sense, often lacking, of what it means to have someone’s phone records in this day and age. That leads Leon to confront, in the opinion’s most sweeping section, Smith v. Maryland, the 1979 Supreme Court decision that the N.S.A. has leaned on extraordinarily heavily in justifying its collection of telephone (and other) records. As I wrote earlier this month, Smith v. Maryland involved a single robbery suspect already known to the police, believed by them to be making threatening calls to a particular witness. It also involved telephones that are hardly recognizable as the same things we carry around in our pockets. As Judge Leon writes, “Some undoubtedly will be reading this opinion on their cell phones.” Not only is the government able to collect more phone data, more easily, and sort it in new ways, “the nature and quantity of the information contained in people’s telephony metadata is much greater, as well.” He calls it all “almost Orwellian.” It is not that he argues Smith v. Maryland should be overturned, but that courts should realize that it’s not talking about what they think it’s talking about, because the meaning of the words has changed:

That is fortunate for the rest of us. Judge Leon’s decision may also open up new avenues for oversight and review; as Ryan Lizza describes in depressing detail in The New Yorker, both have been lacking. The Foreign Intelligence Surveillance Act court only has a place for the government and (sometimes) the phone companies. The law that created it did not contemplate the surveilled bringing challenges—in large part, because they were not supposed to know that they were being surveilled. But that doesn’t mean that they don’t have a constitutional claim, Leon writes. There is, he notes, no language “expressly barring” judicial review, and in any event Congress should not be able to do so “simply because it intends for the conduct to remain secret:

He finds that Larry Klayman and Charles Strange, who brought the suit and are customers of Verizon, the company mentioned in documents about the program leaked by Edward Snowden, have clear standing to bring the case; he writes that they would likely succeed in demonstrating that the program violated the Fourth Amendment (because of that, he does not examine First and Fifth Amendment claims they also bring, though he doesn’t dismiss them). Because they are suffering while the case is being heard, he grants their request for an injunction stopping the government from collecting their data, and telling it to destroy what it has—an order that he stays pending an appeal, but only, he writes, so that the government can get its house in order. Although the injunction only applies to the plaintiffs, he makes it clear that almost any American with a Verizon account, or maybe just a phone, could sue, too, which would effectively end the program. (The A.C.L.U. has already done so.)

The government could win that appeal. Judge Leon notes that judges in other circuits have ruled differently—accepting the application of Smith v. Maryland, for example. But what his ruling does is deprive the N.S.A. of the argument of obviousness: the idea that what it is doing is plainly legal, plainly necessary, and nothing for decent people to worry about. (He says that the government has given him no evidence that bulk collection and analysis are essential to the fight against terrorism.) This judge is worried.

More than that—and this, too, comes across in the Domino’s hypothetical, with its reference to “the government’s book of understatement”—he sounds angry. There is a recurrent note of skepticism about the government’s representations (among other things, concerning its treatment of location data) and dismay at its standard of honesty. Commenting on the government’s attempt to argue that Klayman has no standing—by denying in one place something it has admitted in another—he writes,

There are several exclamation points in this decision. Judge Leon plainly feels that he has been lied to, and that we all have been. And he seems to be done with it. We hear a lot, he writes, about the expectation of privacy, and how it has disappeared in this day and age—don’t we all know we leave digital trails that can be followed? If we have given up on the privacy of our metadata, Judge Leon writes (quoting Smith in part), “I would likely find that is the result of ‘ “conditioning” by influences alien to well-recognized Fourth Amendment freedoms.’ ” In other words, cynicism does not give the government a pass when it comes to its constitutional obligations. And neither should the courts. We are allowed to expect more.