WASHINGTON — There’s the cycle of poverty. There’s the cycle of violence. And then there’s the cycle of gun talk. It starts with a mass shooting. Gun-control advocates blame the deaths on gun-control opponents, who argue, in turn, that none of the proposed restrictions would have had any effect on the incident in question. The debate goes nowhere. The media move on.

Until the next incident, when the cycle begins again.

So with the Roseburg massacre in Oregon. Within hours, President Obama takes to the microphones to furiously denounce the NRA and its ilk for resisting “commonsense gun-safety laws.” His harangue is totally sincere, totally knee-jerk and totally pointless. At the time he delivers it, he — and we — know practically nothing about the shooter, nothing about the weapons, nothing about how they were obtained.

Nor does Obama propose any legislation. He knows none would pass. But the deeper truth is that it would have made no difference. Does anyone really believe that the (alleged) gun-show loophole had anything to do with Roseburg? Universal background checks sound wonderful. But Oregon already has one. The Roseburg shooter and his mother obtained every one of their guns legally.

The reason the debate is so muddled, indeed surreal — notice, by the way, how “gun control” has been cleverly rechristened “commonsense gun-safety laws,” as if we’re talking about accident proofing — is that both sides know that the only measure that might actually prevent mass killings has absolutely no chance of ever being enacted.

Mere “commonsense” regulation, like the assault weapons ban of 1994 that was allowed to lapse 10 years later, does little more than make us feel good. A Justice Department study found “no discernible reduction in the lethality and injuriousness of gun violence.”

As for the only remotely plausible solution, Obama dare not speak its name. He made an oblique reference to Australia, never mentioning that its gun-control innovation was confiscation, by means of a mandatory buyback. There’s a reason he didn’t bring up confiscation (apart from the debate about its actual efficacy in reducing gun violence in Australia). In this country, with its traditions, public sentiment and, most importantly, Second Amendment, them’s fightin’ words.

Obama didn’t say them. Nor did he seriously address the other approach that could make a difference: more aggressive psychiatric intervention. These massacres are almost invariably perpetrated by severely disturbed, isolated, often delusional young men.

Yet even here, our reach is limited. In some cases, yes, involuntary commitment would have made a difference. Jared Loughner, the Tucson shooter, was so unstable, so menacing, that fellow students at his community college feared, said one, that he would “come into class with an automatic weapon.” Under our crazy laws, however, he had to kill before he could be locked up.

Similarly, the Navy Yard shooter had been found by police a few weeks earlier in a hotel room, psychotic and paranoid. They advised him to get psychiatric help. Advised. Predictably, he fell through the mental health cracks. A month later, he killed 12 and was killed himself, another casualty of a mental health system that lets the severely psychiatrically ill — you see them sleeping on grates — live and die wretchedly abandoned.

The problem is that these mass-murder cases are fairly unusual. Take Roseburg. That young man had no criminal history, no psychiatric diagnosis beyond Asperger’s, no involvement in public disturbances. How do you find, let alone lock up, someone like that?

There are 320 million Americans. Schizophrenia affects about 1 percent of the population. That’s about 3 million people. Only a tiny fraction are ever violent — and predicting which ones will be is almost impossible.

Loner, socially isolated, often immersed in a fantasy world of violent video games. There are myriad such young men out there, but with different ages of onset, in different stages of derangement. Only a handful will ever harm anyone. What to do? Forcibly apprehend them, treat them, put them on perpetual preventive parole? By the tens of thousands?

Committing the Jared Loughners would have an effect. But even they are the exception among the shooters. Yet “commonsense” gun control would do even less. Unless you’re willing to go all the way.

In the final quarter of his presidency, Obama can very well say what he wants. If he believes in Australian-style confiscation — i.e., abolishing the Second Amendment — why not spell it out? Until he does, he should stop demonizing people for not doing what he won’t even propose.

Charles Krauthammer’s email address is letters@charleskrauthammer.com.

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