An obviously deranged man killed six people with a legally purchased and legally carried pistol on Saturday, and the only thing we're arguing about is whether he was listening to Sarah Palin.

The debate over what caused Jared Lee Loughner to do what he did is a waste of time. He was obviously suffering from paranoid schizophrenia or a similarly destabilizing emotional disorder; parsing out the particular determinants of his apparent belief that grammar is mind control will not solve any puzzles. The thing about genuine craziness is that it rejects parsing, invents its own reasons, and resists explanation. Accusing Sarah Palin and assorted other teabaggers of somehow inspiring or abetting this action is like accusing Scooby Doo of inspiring Sam Berkowitz's affection for his neighbor's talking dog. The workings of a properly delusional mind are unfathomable.

There is of course one thing we can squarely and firmly place the blame for these killings on, aside from Loughner himself: The handgun he used to carry them out. Arizona essentially has no gun laws. Loughner committed no crime when he purchased the gun, no crime when he loaded it, and no crime when he carried it to the Safeway. He was obviously crazy to virtually everybody who encountered him in recent months except for the dealer who sold him the gun. He was too crazy for community college, but not too crazy to buy a Glock.

But—aside from a heroic effort on the part of MSNBC that seemed to begin around 1 p.m. today—no one's even bothering to put up a heartfelt argument about whether we should consider enacting barriers to the purchase of semi-automatic weapons by plainly insane people. It's a dead debate, lost long ago. No one's going to listen to gun control advocates, so what's the point? It's more fun, and less politically verboten, to talk about whether or not open hatred and violent rhetoric is appropriate in our politics.

It's a perverse surrogacy. The reason six people were killed on Saturday is that Loughner had access to a firearm. But a consensus has emerged that preserving access to firearms for the public at large is worth the occasional mass killing because the alternative—registering firearms, requiring competency evaluations before selling them—is too onerous. So instead we fight about whether a subsidiary reason may have involved nasty things some people said, because there is no consensus that restricting our freedom to say nasty things to and about one another is too much of a burden.

Ask yourself which measure, had it been in place in the three years prior to the killings, would have been more likely to prevent them: A pledge from Sarah Palin to refrain from violent rhetoric, or a requirement in Arizona that all gun sales be accompanied by a note from a mental health professional certifying competence. Thousands have been demanding the former for the past two days; I haven't heard anyone propose the latter.

Because gun control is a loser. Americans would rather have occasional mass killings and some agita over political rhetoric than reasonable restrictions on the rights of crazy people to buy guns. And no politicians have the courage to try to convince them otherwise. So some nine-year-old girls have to die now and again.

This isn't to say that Palin and her ilk shouldn't be condemned for embracing murderous and treasonous rhetoric and imagery. They should. But there's nothing to suggest that Loughner wouldn't have done what he did if Palin hadn't been saying what she said.

[Image, top, via Shutterstock.com. Photo of Loughner via his MySpace page]