The three suspects commonly cited are the purported danger of certain firearms, mentally ill individuals and modern forms of entertainment. They all make plausible culprits, until you look closely.
The first is our old nemesis the "assault weapon." The Newtown shooter used a Bushmaster semiautomatic rifle, which resembles a military model, and several 30-round magazines. President Barack Obama and several Democratic senators are therefore calling for a renewal of the "assault weapons" ban that expired in 2004.
But the guns they would ban are functionally identical to innumerable guns that would not be outlawed. Contrary to myth, these firearms don't produce bursts of automatic fire, don't "spray" bullets and aren't any more lethal than other semiautomatic guns. They are exceptional only in how they look.
What would a new ban achieve? As Reason's Jacob Sullum noted, Connecticut forbids the same assault weapons covered by the old federal law. Under its terms, however, the gun used by Adam Lanza was legal.
The gun-control advocates also want to prohibit high-capacity magazines, limiting them to 10 rounds. The lifesaving value of this change is likely to be close to zero. Ordinary street thugs rarely fire many rounds, and those intent on slaughtering large numbers of victims can carry multiple magazines and multiple guns. That's exactly what Lanza did.
The theory is that a shooter who has to pause to reload can be stopped. But switching out a magazine takes only seconds. Florida State University gun scholar Gary Kleck says he knows of only one case where bystanders overcame a mass shooter when he stopped to reload.
Jared Loughner, who killed six people in Tucson, was tackled only after reloading, when his gun jammed. Lanza, shooting docile first graders in a confined space, didn't have to worry they would subdue him.
Many of the suggestions for averting the next massacre involve how we handle the mentally ill. Sen. Dick Durbin, D-Ill., called for denying guns to "those with a history of mental instability."
That's a bit like looking for your keys where the light is good instead of where you dropped them. We don't know that Lanza suffered from mental illness. His developmental disorder, Asperger's syndrome, is not associated with violence. Lori Shery, president of the Asperger Syndrome Education Network, told The New York Times his disorder was about as pertinent to the crime as the color of his hair.
Even if Lanza had some serious psychiatric ailment, it may explain nothing. The vast majority of mentally ill people are not dangerous, and the vast majority of violent criminals are not mentally ill.
Federal law already bars sales of guns to anyone declared mentally incompetent by a court. Durbin wants to improve state reporting of mental health records, which makes perfect sense. But broadening the criteria for mental-health disqualification, as others suggest, would punish millions of people who pose no risk. It's important to protect the rest of us from the mentally ill, but equally vital to protect them from indiscriminate sanctions.
So desperate are some people to make sense of the slaughter that they resorted to the flimsiest of straw men. Sen. Joe Lieberman, I-Conn., fretted about "the impact of violence in the entertainment culture."
Senate Commerce Committee Chairman Jay Rockefeller, D-W.Va., took a more threatening tack: "Major corporations, including the video game industry, make billions on marketing and selling violent content to children. They have a responsibility to protect our children. If they do not, you can count on the Congress to take a more aggressive role."
Seriously? If violence in media causes violence in the real world, how do they explain that homicides are less than half as common today as they were in 1980, before video games took off?
Does anyone think the new film of "Anna Karenina" will cause a rash of train suicides? Has Rockefeller heard of the First Amendment?
He evidently thinks video gamers can't understand the difference between fantasy and reality. Funny thing: A lot of politicians have the same problem.