Self-righteousness is liberating. The same people who are most exercised about guns in America, and want to ban and even confiscate entire categories of firearms, know little about them and evidently feel no compunction to learn.

The worst terror attack in the United States since 9/11 has become the occasion for another frenzied, poorly informed push for new gun restrictions.

President Obama gave a prime-time address on the terror threat, in which he resolutely re-affirmed the status quo in the campaign against ISIS. Except that he hopes that gun control, one of the signal political and policy failures of our time, will now be deployed to help foil the apocalyptic terror group.

Almost every time there is a mass shooting, there is a rush to push old gun-control chestnuts regardless of their applicability.

The San Bernardino terror couple didn’t buy their guns at a gun show (making the effort to close the so-called gun-show loophole irrelevant); they weren’t on the terrorism watch list (so the proposal to ban people on the list from buying guns wouldn’t have stopped them); and Syed Farook passed a background check when he bought two handguns (rendering calls for universal background checks moot).

The president and The New York Times, which saw fit to publish a front-page editorial for the first time since it thundered against Warren Harding in 1920, have fastened on the two “assault weapons,” AR-15s, used in the attack. The Times called them “weapons of war, barely modified.” President Obama referred to them as “powerful assault weapons.”

On this question, the left has fallen for its own propaganda. Decades ago, gun-controllers decided to play on the confusion between semi-automatic versus automatic weapons to push for a ban on nasty-looking assault weapons, even though they are, for the most part, functionally indistinguishable from other semi-automatic rifles.

The AR-15 is one of those semi-automatic guns. It isn’t exotic or particularly powerful. It is the most popular rifle in the country. At least 3.5 million are in circulation. It is accurate and light, without much kick. You wouldn’t use it in combat and, in fact, wouldn’t necessarily use it to hunt.

A .223-caliber gun, it is less powerful than many handguns. Some states forbid .223-caliber rifles in deer hunting because they aren’t powerful enough to reliably take down the game.

If gun-controllers know any of this, they hide it well. And they don’t seem to care that a prior version of the assault-weapons ban, in effect in the 10 years after 1994, was wholly ineffectual.

A Department of Justice-backed study concluded, “Should it be renewed, the ban’s effects on gun violence are likely to be small at best and perhaps too small for reliable measurement.” (Rifles of all types, let alone assault rifles, are used in gun homicides only rarely.)

The proposal to keep people on the terrorist watch list from buying guns sounds sensible, yet it is problematic in that it denies people an explicit constitutional right on the basis of little or no due process. Last year, the Times itself inveighed against “the shadowy, self-contradictory world of American terror watch lists.” If the watch list is to become a no-gun list, it has to be cleaned up and listees should have an opportunity to challenge their status upon attempting to buy a gun.

Such a prohibition would affect a tiny slice of gun purchases and would likely be mere symbolism, like the assault-weapons ban. The overriding reality that gun-controllers ignore is that almost all gun homicides are committed with handguns in routine street crime, handguns that are often obtained in informal networks operating outside the gun rules we already have.

But please don’t confuse the anti-gun campaigners with facts. Their ignorance is invincible, and necessary to their crusade.

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