On the Monday after Christmas a bullet left a firearm, traveled across two streets, a front yard, and a vacant lot before striking a house and hitting the head of a three-year-old Minneapolis boy, Terrell Mayes, who was climbing the stairs with his three other brothers to hide in a closet when they heard the first gunshots. Terrell died the next day. Had the bullet gone a little farther to the east, it would have missed the house and struck a neighboring elementary school.



Tragedies like this bring out both sides of the endless argument in the U.S. over guns, with local politicians and the police calling for the end of gun violence and with gun advocates reminding us that guns don't kill, people do. The standoff in the quarrel over guns suggests that we need to reframe the terms of the debate, and the case of this innocent boy getting shot inside his house suggests one way of doing so.



As Senator Daniel Patrick Moynihan once put it, "guns don't kill people, bullets do." The problem of gun violence begins and ends with bullets, so let's focus on them.



It's cheap to buy handgun bullets, but the real cost of that one stray bullet is enormous. Let's leave aside the inestimable cost to Terrell's family of his death and look instead on the cost the rest of us will pay for his loss.



A study published in the Journal of the American Medical Association calculated a mean medical cost per gunshot injury of about $17,000 in the United States in 1994 (almost $25,000 in today's dollars), producing $2.3 billion in lifetime medical costs, of which $1.1 billion or nearly half was paid by US taxpayers. The study concludes that "Gunshot injury costs represent a substantial burden to the medical care system."



Add to that the cost of police work related to gun violence and the cost of trying and possibly incarcerating shooters, which averages $43,000 annually, and a conservative estimate of the cost borne by our health and judicial system of that one stray bullet is $68,000 the first year and roughly two-thirds of that every year for as long as the perpetrator sits behind bars.



If we include the loss of projected lifetime earnings -- $1.2 million for high school grads and roughly double for college grads -- and the indirect costs of gun violence on people's stress levels and home values, the long-term costs skyrocket.



For those who shrug and say that this is the price we have to pay for our right to bear arms, let's look at that stray bullet in terms of another cherished freedom: our property rights. In architecture we spend a lot of time working within the property boundaries, and ensuring that homeowners receive the level of safety and security required by building codes.



But bullets respect no property rights. The bullet that killed Terrell flew across four pieces of private property and two public rights of way before it hit him. One bullet, in other words, can negate all that we have put in place to protect people and their property and, as such, it represents an abrogation of our freedom as much as a protection of it.



In 1993, Senator Moynihan proposed that the Federal government tax ammunition, with a 10,000 percent tax on the deadliest projectiles. The gun lobby called his proposal laughable, and it went nowhere, but it is an idea worth revisiting. Instead of taxing ammunition, we might consider a more market-driven alternative: charging the ammunition industry for the costs incurred when their products are used to kill or maim people.



We know who makes bullets and we know how much it costs us when criminals use their products to harm others. By charging the industry for these expenses, companies would have an incentive to put in place better precautions to prevent their products' misuse. It would also reduce the costs to taxpayers, while saving lives and improving the quality of life for the millions of people who live in fear of gun violence.



The constitution may give us the right to bear arms, but it doesn't guarantee us the right to have cheap bullets. Nor does it give some the right to violate the property rights of others with ammunition that make us unsafe in and around our own homes. By making the deadliest bullets cost prohibitive, we would do a lot to protect the constitutional rights of the rest of us.