
It would seem now that every few months there is a mass murder outbreak within the country most famous for a "right to bear arms". Indeed, the rate of mass shootings is accelerating[1], and they are becoming deadlier. The conflict of interests has been brought again to public debate with the recent Stoneman Douglas High School shooting [2], where the U.S. president, Donald Trump, offered his prayers and condolences, ordered flags be flown at half-staff, and then suggested arming teachers as a deterrent [3]. In contrast student survivors have demanded stricter gun controls [4], a position rejected by pro-gun activists as being ineffectual at best and dangerous at worst insofar it provides opportunities for armed homicide. The question of who is correct in this matter is an empirical one whereas, the question of what alternatives can be feasibly be implemented, is a political one.
Several seemingly obvious statements need to be made, at least in part because the arguments are often raised in the debate. The gun is not the only deadly technology available, and a determined person can, of course, carry out a homicide through other means. But the availability of a deadly ranged technology does make it easier. Ceteris paribus, because humans are imperferct, the greater the quantity of guns, the more opportunities there are for deliberate misuse or mishap; in a tragically prescient article the New York Times [5] pointed out that the United States and Yemen (which is the midst of a civil war) are two exceptional countries which both have a high number of guns per capita and mass shooting per capita. Likewise it should be unsurprising to discover that restrictions on firearms (e.g., restricted purchase, storage requirements) result in less firearm injuries, intentional or otherwise [6]. The latter point is important - gun suicides far exceed gun homicides and given that suicides are surprisingly a split-moment decision, an easy means to perform such an act correlates with the event [7].