The usual gun extremists largely went into hiding immediately after the obscenity in Connecticut. The National Rifle Association offered only a flowery expression of sympathy for the victims. Real brave, aren’t they?

One foe of gun control who did speak out was Michigan Rep. Mike Rogers, a Republican. He said the “more realistic discussion” is “how do we target people with mental illness who use firearms?”

Actually, not realistic at all. It’s easy to identify a mentally ill person with access to firearms once he’s massacred a kindergarten class in about 15 seconds. We also learned of warning signs after James Holmes shot up a movie theater in Aurora, Colo., and Seung-Hui Cho did his deadly rampage at Virginia Tech. All had been good students, by the way.

Banning weapons of war would be a lot easier and less intrusive than psychoanalyzing anyone who wants to buy a gun. But as the shock of Newtown, Conn., mellows, the new theme of gun-rights absolutists is coming together: The problem is not widely sold assault weapons with magazines capable of carrying 30 rounds. It’s crazy people who get their hands on them.

As it happened, an insane Adam Lanza was able to kill his mother and rapidly mow down 27 innocents at Sandy Hook Elementary School because his allegedly not-disturbed mom kept a Bushmaster .223 caliber rifle — among other mass-killing machines — in their tidy home. Reports portray Nancy Lanza as a “high-strung” divorced mother trying to deal with an antisocial adolescent. That is hardly a unique set of circumstances. Who would have taken her guns away?

My in-laws, originally farm people from Indiana, owned a spread in New Milford, Conn., a town about 16 miles from Newtown and with similar demographics. Over the years, cul-de-sacs for people from New York and its inner suburbs rose around us. The newcomers saw the pastoral setting as a wholesome place to raise families. Most of them were fine neighbors, but some imagined that gun arsenals would make them into the country people they clearly were not.

We had some ancient rifles that we used for target practice on one of the fields. But on many afternoons, the entire valley’s peace was jarred by the rapid firing of exurbanites playing warrior. Similar complaints had been aired in Newtown.

About troubled young people: One day we discovered that the well-house had been destroyed. After rebuilding it at some cost, we caught two boys tearing the new structure apart. My husband grabbed the ringleader by the collar and yelled at him.

That evening, the father — with ringleader in tow — visited the farmhouse to ask my husband whether he had roughed up his boy (no doubt the boy’s story). My husband got annoyed and said, “You’re not hearing me.” The father then conceded that his son was upset after “the divorce.” As Dad turned his back, the juvenile gave my husband the finger.

A messed up kid, we agree, but also a father loath to see his child as seriously troubled. Nancy Lanza had a real tough case in Adam, but was in such deep denial that she even took him out for shooting practice.

Given the realities, a background check of a gun buyer’s mental condition would logically include relatives and friends. Who wouldn’t have given Nancy Lanza alone a clean bill of mental health?

Our neighborhoods are full of loners and moody adolescents who dress in black. The vast majority are harmless. Short of arming grade-school librarians, the only sane way to curb the mass killings would be to cut off the flow of mass-killing machines. That’s being “realistic.”