The news that the parents of the children massacred two years ago in Sandy Hook, near Newtown, Connecticut, by a young man with a Bushmaster semi-automatic rifle, were undertaking a lawsuit against the gun manufacturer was at once encouraging and terribly discouraging. The encouraging part is that those parents, suffering from a grief that those of us who are only witnesses to it can barely begin to comprehend, haven’t, despite the failure to reinstate assault-weapons bans and stop the next massacre, given way to despair. Like Richard Martinez, after his son was murdered by a weapon that should never have been in the hands of a lunatic, or anyone else, for that matter, they’re allowing themselves to be angry, and then turning their anger into action: they’re naming the business that helped kill their children and asking a court to hold that business responsible.

The filed complaint—the numbered paragraphs give it an oddly religious feeling, like theses nailed to a church door—is worth reading in full, however painful that might be, not only because of the unbelievable suffering and cruelty it details on that terrible morning but also because it offers, in neatly logical fashion, an indisputable argument: the gun manufacturer is guilty of having sold a weapon whose only purpose was killing a lot of people in a very short time. Despite the Bureau of Alcohol, Tobacco, Firearms and Explosives having previously declared that such weapons “serve a function in crime and combat, but serve no sporting purpose,” Bushmaster sold it anyway—and precisely on the grounds that it could kill many people, quickly. “Forces of opposition bow down. You are single handedly outnumbered,” the advertising copy read.

The lawsuit is discouraging because the death-by-gun lobby has successfully advocated for legislative prophylactics that prevent gunmakers, almost uniquely among American manufacturers, from ever being held responsible for the deaths that their products cause. If a carmaker made a car that was known to be wildly unsafe, and then advertised it as unsafe, liabilities would result. The gun lobby is, or believes itself to be, immune. Some experts have outlined legal principles that might let sanity triumph, but it is hard to think it will. (Right-wing judges tend, these days, to be more creative than liberal ones in creating legal precedents that no one ever before imagined possible.)

Indeed, one of the ironies of the whole story is that there already is a long-standing ban on truly automatic weapons—machine guns—whose legality not even the N.R.A. or their allies dispute. If anything, they tend to make a sniffy point of discriminating actual machine guns from mere semi-automatic ones, among them the Bushmaster. (Back in the twenties, the availability of the tommy gun to gangsters meant that the police were often brutally out-gunned.) But all of the talk about legal and illegal weapons, automatic and semi-automatic—as about the treatment of the psychologically troubled—evades the simple, central point: it ought to be very, very difficult, as it is in every other civilized country, to get your hands on a weapon whose only purpose is to kill people quickly. The N.R.A. and their allies make it very, very easy.

The underlying politics of gun control has always been the same: the majority of Americans agree that there should be limits and controls on the manufacture and sale and ownership of weapons intended only to kill en masse, while a small minority feels, with a fanatic passion, that there shouldn’t. In a process familiar to any student of society, the majority of people in favor of gun sanity care about a lot of other things, too, and think about them far more often; the gun crazy think about guns all the time, and vote on the issue with fanatic intensity.

On some subjects on which we wish sanity and common sense could prevail over fanaticism and irrationality, it’s apparent that the mental work is not yet finished or even entirely begun. In public life, there are subjects about which the mental work is done, but the moral work still needs doing. Or to put it with another neatly alliterative pair, where the intellectual work is not yet complete even as the inspirational work takes flight. The argument over gay marriage was only the most recent one to show that, with the mental work done, the moral work could begin, and the right result would follow: the unthinkable, fifty years ago, first got thought through, and then got done. On the other extreme, it’s obvious that our thinking through of capitalism and its inequalities and how to mend them anew has hardly begun; the Occupy movement collapsed for that reason. The same is true about the vexing problem of sexual violence at universities—the mental labor of sorting through the obvious right of women to be safe from casual sexual assault, and that of the accused to be free from unsupported accusations—is only now underway. You know that your intellectual labor isn’t finished when you bleed natural allies—people who are inclined to agree with you, but are alarmed by the unconsidered consequences of your position.

But on the problem of gun control, no matter how far we may seem from a sane solution, the public deliberations are finished. Instead of bleeding natural allies, new ones join all the time, including the voters who rejected attempts to eliminate checks and delays on weapon sales in the last election. No honest or scrupulous person can any longer reject the evidence that gun control controls gun violence. It can be rejected only by rage and hysteria and denial and with the Second Amendment invoked, not as a document with a specific and surprising history, but as a semi-theological dogma. The argument has been revealed conclusively to be between people who actually want to reduce the number of gun massacres and those who prefer an attachment to lethal symbols of power. (There are other symbols of personal autonomy, safer to small children.)

The majority is there, and the mental work is accomplished. This means that though the moral work—of persuasion, conviction, and shaming—needs to go on, we can be confident that it will go on and win, too, in the long run. There is nothing so irresistible as an idea that happens to be true. Piece by piece, legislation by litigation, the curse will be lifted. Time and temperament and patience will win out. This is the belief that the Victorians called “progressivism” and it is still much mocked. But the neat thing is that it happens to be true. There are many issues—the overwhelming majority—on which we need an ongoing public “conversation.” On a few, we don’t. Gun control stops gun violence. Gun possession does not deter crime; it merely makes it more lethal. Making these inarguable truths into necessary law takes the work of persuasion and legislation and litigation. The mental work finished, the moral work goes on, often in modest invisibility. Every day, something good happens at the state or community level that makes getting guns a little harder—and keeps families a little safer. That it might happen a little faster is a rational hope, and a proper holiday wish.

Correction: A previous image published with this post was replaced because it had been mislabelled by the photo agency.