Some wallow in the idea that they are being watched, their civil liberties endangered, simply because a handful of electrons they generated were among the vast billions being reviewed in a high-stakes antiterrorism effort. Of course, many are motivated politically or ideologically to oppose robust intelligence-gathering aimed at fending off Islamist terrorism. Criticism from that quarter can be left to lie where it fell.

All of that being said, it is at least theoretically possible that information could be misused to the prejudice of innocent citizens, which would be both a shame and a crime. But it makes about as much sense to deny intelligence agencies access to information necessary to defend the nation because some of that information theoretically could be misused as it does to deny guns to police because they could be turned on the innocent.

Nor do these programs violate the law. Start with the Constitution. The applicable provisions lie in two clauses in the Fourth Amendment. The first bars “unreasonable searches and seizures.” The second provides that “no Warrants shall issue, but upon probable cause” established by affidavit, and it requires that warrants describe with particularity what or who is to be seized, and from where.

Notice that the first clause does not forbid warrantless searches, only unreasonable ones. And the second simply creates a warrant requirement that is read, with some exceptions, to bar evidence at trial if it is obtained without a valid warrant.