Soon after the Isla Vista mass shooting, an e-mail from Breitbart News, one of the slicker right-wing Web sites, popped into my inbox. Considering the source, the breathless subject line was startling: THE WORLD’S FIRST SMART RIFLE - NOW IN SEMI-AUTO

A smart gun, as you probably know, is one that can be fired only by an authorized person, such as the weapon’s legal owner. Anyway, that’s the usual meaning. The way a smart gun works, smartplanet.com explains, “is that the gun’s biometric system is set up to recognize the rightful user through a unique identity marker such as a person’s fingerprint, magnetic rings, RFID chips or other proximity devices.”

A smart gun is a technological fix. If guns were smart, we wouldn’t need to worry so much about their falling into the wrong hands—such as the hands of a toddler who might playfully point one at his sister and pull the trigger, the hands of a troubled teen-ager who might borrow Dad’s hunting rifle to commit suicide, or the hands of a thug who has just wrested away a cop’s pistol.

Does it surprise you that the National Rifle Association opposes any attempt to mandate or encourage the use of smart guns, or even study their potential? Or that, earlier this month, when a couple of gun-shop owners decided to stock a few, they changed their minds after being smeared online as traitors and Communists, and threatened with arson and death?

Me neither. That’s why I did a double take at that enthusiastic-sounding subject line. After all, Breitbart, like every other site that caters to the populist Republican base, is a faithful lapdog of the N.R.A.

The mystery cleared up when I opened the e-mail. It wasn’t a news story but a “special message”—that is, an advertisement. And the rifle being hawked to the Breitbart readership is indeed “smart,” but in an altogether more sinister way:

TrackingPoint smart rifles, developed by military experts and a team of over forty engineers, have virtually eliminated shooter error and adverse conditions from the firing equation. Our Tag-Track-Xact system can more than double the proficiency of a skilled shooter and let them take shots they’d never before even attempt, while capturing it all on video. TrackingPoint smart rifles increase effective range, maximize accuracy, and almost entirely eliminate the possibility of errant shots. We’ve combined our technological innovations with the best hardware in the American gun industry has to offer, fusing our integrated trigger and groundbreaking scope system with 7.62, 300 BLK & 5.56 Semi Auto Platforms along with .338 Lapua and .300 Win Mag bolt action rifles to create a firing system unparalleled in the world today.

For the full effect, I clicked through to a Web site, whence I was taken to a video, which I present here for your convenience. It’s a must-see, believe me.

The gun is expensive, from around ten thousand to more than twenty thousand dollars. But price is no object if you’re a wealthy but myopic, arthritic, or just unskilled “sportsman,” or an enforcer for a Mexican drug gang, or a roving troubleshooter (as it were) for a moderately well-heeled jihadist network or an excessively pro-Second Amendment nongovernmental militia.

The effective sure-kill range of “the world’s first smart rifle” is a thousand yards—a tad more than half a mile, a tad less than a kilometre. The distance between the sixth-floor window of the Texas School Book Depository and the Presidential limousine was eighty-eight yards.