Premise 1: Killer Knows Best

What makes one gun more lethal than another? Ever since Sandy Hook, the media has bombarded us with gun jargon. We've learned about flash suppressors and high-capacity magazines, threaded barrels and pistol grips. We've heard that these features are bad features, dangerous to children and other living things. The expired federal assault weapons law used to ban any gun with two or more of them. The new New York law bans them all.

But we've also heard that gunmakers find ways to skirt these constraints. For instance, some manufacturers evaded California's quick-reload restriction with a "bullet button" that allows shooters to release a magazine with a bullet tip instead of a fingertip. It's hard for plodding legislatures to keep up with eager manufacturers, who have every incentive to invent the most lethal legal weapon possible.

So if not the legislators, who should determine which guns are too deadly? Who in America most appreciates a gun's killing potential?

The killers, of course. They're the ones who want to kill. They're the ones who pay attention to the features that help them do it. Of course, killers are not necessarily the most scientific buyers. They may choose big black rifles with scary names over more lethal alternatives. But that doesn't matter because it's not actual killing power we're after so much as perceived killing power. We want to eliminate the guns that most appeal to people who want to kill other people.

No, I'm not suggesting that we send out surveys to convicted murderers. We have a much more reliable tool: crime statistics. The ATF and other law enforcement agencies already trace the guns and ammunition used in violent crimes. Determining the killers' favorite weapons should not be difficult.

But how do we use the information? If we ban specific models, the manufacturers will simply release new models with slight variations and carry on as before.

Which brings me to...

Premise 2: Guns Kill People

"Guns don't kill people, people kill people." So guns rights supporters recite like a mantra. The gun is just a tool, they say. Shall we penalize manufacturers and retailers any time some product they sell happens to be used in a crime?

But guns are very different from other products. Unlike candlesticks, ropes, and lead pipes, guns are specifically designed to kill, and a far larger proportion of them have been used for that purpose. Hardware stores do not make much money from lead pipe murderers, but firearm manufacturers and retailers make a handy profit from death. Guns have killed nearly 400,000 Americans since 1980 and injured millions, which adds up to a robust trade in murder weaponry.

The real money, however, is not in crime guns. The real money is in fear guns--the guns people buy to protect themselves from armed killers. In what the economists might call a "virtuous" circle, gun sales increase gun homicides which increase gun sales. In short, the more people die, the higher the profits for the firearm industry.

So it seems only reasonable that companies that profit from gun crime should pay for the violence their merchandise inflicts on the country.

Which brings me to...

Conclusion: Let the Killers Choose, Let the Profiteers Pay

Rather than ban particularly lethal gun models as most guns laws have attempted to do, I propose a "Death Tax." The more deadly the gun, the higher the tax. A Death Tax will not eliminate the particularly lethal guns, but it will reduce their availability and the number of lives they destroy.

How do we determine the lethality? We let the killers decide. At the end of each year, we tabulate the guns used in violent crime and assess a substantial tax to the manufacturers that built them and the retailers that sold them.

The tax should reflect the age of the guns and the popularity of the model. The Smith and Wesson .38 is one of the most popular crime guns because it is one of the most popular guns overall, not because it's the most lethal. The tax should be highest on recently sold guns in which a relatively high proportion have been used for crime. We can also add multipliers for mass-shootings and juvenile homicides.

The intent of the Death Tax is to reverse the incentive structure. Currently, manufacturers and retailers have strong incentives to meet the demand for assault rifles and other especially deadly firearms. Manufacturers add bullet buttons and other workarounds to keep their guns as lethal as possible. Retailers stock these guns and sell them to people they shouldn't. If these companies have to pay a stiff enough price for selling guns to killers, they will start making greater efforts to avoid doing so. Manufacturers will make guns that are less attractive to mass-murderers and gangsters. Retailers will avoid assault rifles and employ more rigorous checks. The price of the most lethal guns will rise.

The Death Tax would not stop the killing, but by making it harder to kill people, we could at least reduce the terrible cost that guns inflict on the country--perhaps much more effectively than trying to ban the weapons that politicians deem deadly.