Onto the continuing tragedy of American gun violence are now piled many kinds of grotesquerie, not least the e-mails, sure to come to any parent with kids still in school anywhere in the country, offering “tips on talking to children about violence” and promising that your child’s school “has been performing lockdown drill protocols that our security team and consultants have recommended to ensure that we are prepared in the unlikely event that an incident occurs.” We have normalized gun killings to the point that we must now be reassured that, when the person with the AR-15 comes to your kid’s school, there’s a plan to cope with him. (That the planning is almost worthless is proved by the killings in Florida, where the murderer may have taken advantage of his knowledge of the lockdown protocols in order to kill more students.) Here, though, are four simple truths worth saying again, in the aftermath of the Florida massacre, about gun control and gun violence.

1. The gun lobby, and the Republican Party it controls, have accepted as a matter of necessity the ongoing deaths of hundreds of children as the price that they are prepared to pay for the fetishization of weapons. The claim of this lobby’s complicity in murder is not exaggerated or hysterical but, by now, quite simple and precise: when you refuse to act to stop a social catastrophe from happening, you are responsible for the consequences of the social catastrophe. If you refuse to immunize your children and a measles epidemic breaks out, you are implicated in the measles. If you refuse to pay money for sewers and cholera breaks out, you are complicit in the cholera. Acts have consequences. This complicity includes all of the hand-wringers and the tut-tutters and the “nothing to be done”-ers as much as the N.R.A. hardcore. Many people have predicted, repeatedly, that one gun massacre would lead to the next—and that more gun massacres would probably take place in one year in America than in the rest of the civilized world combined—and they have been proved right, and then right again. Since everyone knew that this would happen again, those who did nothing to stop it happening again—and who did everything they could to see that no one else could do anything to stop it happening again—are complicit when it happens, again.

2. The claim that gun massacres are mysterious or difficult or bewildering or resistant to legislation is a lie. When people say that nothing can be done because this law wouldn’t stop this one, or that law that one, they are acting in ignorance of the most significant and obvious fact: that no other modernized society experiences remotely the frequency or the horror of American gun killings. There is no mystery at all to stopping this, if there is a minimal will to stop it. A huge, repeated body of social science shows that gun control controls gun violence, and largely eliminates gun massacres, within the normal limits of human action. (People still die of infections; that is no argument against the efficacy of antibiotics. Crimes continue on our streets; that is no argument against the thousand small sanities that have so dramatically reduced violent crime in our cities.) If we had gun laws like the gun laws in Canada or in Britain, we would have gun violence at the level that it exists in Canada and Britain. There is no special American quiddity that would alter this—to insist otherwise is as irrational as insisting that American kids shouldn’t be immunized because American kids have a different kind of immunity than other kids. They don’t. Building small barriers to gun violence reduces all gun violence. The lesson of contemporary social science is that small difficulties have great effects; make crime harder and you have much less crime. Make getting guns harder and you will have fewer people using them. Merely make gun ownership as demanding as, say, car ownership, with a license to obtain and insurance to buy, and you will see a drastic reduction in gun violence and perhaps a near-end to the mass killings of children.

Further Reading New Yorker writers respond to the Parkland school shooting.

3. The Second Amendment is not a barrier to gun sanity. The reading, from left to right, of the amendment was—until the day before yesterday, historically speaking—that it provided no guarantee to the individual ownership of guns. The notion that it does is novel, radical, and wrong.

4. The attempt to turn the question of gun violence into a question of mental health is obscene. Of course, people who kill children en masse are crazy. That’s the given. Saying this says nothing; every country contains mentally ill and potentially violent people. Only America arms them. When Donald Trump, who last year signed a bill to end a mild Obama-era rule designed to keep mass-killing weapons out of the hands of people with certain mental illnesses, talks about reporting people who are “mentally disturbed” to the proper authorities—well, irony piles upon irony, and the only adequate tribute is contempt and silence.