A few days ago, the NRA inadvertently said something reasonable.

This, in response to a series of protests in Texas. It seems advocates of the right to carry firearms openly have taken to showing up en masse at public places — coffee shops, museums, restaurants, etc. — toting shotguns and assault rifles. So say you’re snapping photos at Dealey Plaza, and up sidles some guy with an AK slung over his shoulder.

That sudden dryness of mouth and tightness of sphincter you feel is not reassurance.

“This is terrifying,” a visitor from Washington state told the Dallas Morning News. “We have guns in our house, but we don’t walk around with them. … This is shocking.”

The NRA seemed to agree. In an unsigned online editorial, it stated the obvious, calling the practice of bringing long guns into public places “dubious,” “scary” and “downright weird.”

Days later, having come, well … under fire from Texas gun groups, the NRA was in retreat, apologizing and blaming this rare lapse of lucidity on a staff member who apparently failed to drink his full allotment of Kool-Aid. The organization assured its followers that it still supports the right of all people to bring all guns into all places.

One gets the sense, when people argue for these “guns everywhere” policies, that they see themselves as restoring some frontier spirit lost in the passage of centuries. A few weeks back, former Sen. Rick Santorum contended on “Face the Nation” that “gun crimes were not very prevalent” in the Old West because everyone was armed.

But they weren’t. In his book, “Gunfight: The Battle Over the Right to Bear Arms in America,” UCLA professor of constitutional law Adam Winkler reveals that gun control in the Old West was actually quite strict. In Dodge City, you were required to turn in your guns when you got to town. The iconic Gunfight at the OK Corral was ignited when Wyatt and Virgil Earp tried to enforce a similar ordinance in Tombstone, Ariz. So the idea that everyone in the Old West was packing is a relic of TV and movie westerns. It is not history.

And while the modern gun rights movement is usually regarded as a conservative construction, Winkler writes that it was actually born of liberal extremism. It seems that in 1967, heavily armed Black Panthers walked brazenly into the California statehouse as a group of children were readying for a picnic with the new governor, Ronald Reagan.

The Panthers saw this as an exercise of their constitutional rights. Reagan and other conservative Republicans saw it as a threat and crafted laws to stop it from happening again. The future president said, “There’s no reason why on the street today a citizen should be carrying loaded weapons.”

In a movement where any deviation from orthodoxy is regarded as heresy, Guns & Ammo magazine recently disappeared a columnist who wrote that gun owners should accept some form of regulation. And now, an NRA staffer has been disavowed and presumably sent off to be re-educated.

This self-reinforcing groupthink stifles meaningful debate on America’s gun problem and speaks volumes about the mind of the gun rights movement. It will fight for you to take an AK into McDonald’s. But you are not allowed to question whether you should.