Back in the Pleistocene epoch, when you and Mrs. Knabe decided to wed, as part of the condition for being granted a marriage license, you were both required to undergo a blood test to prove you were free of syphilis. In the same epoch, during my training in a public hospital, I was compelled to immediately report suspected case of virulent tuberculosis to the local public health authorities for possible quarantine. In 49 states (the exception being New Hampshire), the law demands the use of a seat belt at all times. Failure to comply results in a fine of varying amounts. These examples illustrate the principle that under certain circumstances the government may limit individual liberty to protect the public health. While the nature of those circumstances and that interest continue to be the source of ongoing debate, the principle itself is firmly rooted in both law and the ethics.
In 2010, there were >30,000 firearm related deaths in the United States. That number would place gun related deaths as the 12th most common cause of mortality, and the 4th most common preventable cause of death behind those related to smoking, obesity, and motor vehicle accidents, all of which are subject to a wide variety of public health efforts . The majority of gun related deaths are suicides, and as such are powerfully amenable to prevention, since most suicidal patients remain at high risk for very short periods of time, and the absence of an available firearm during these periods would constitute an effective prophylactic.
So why we don't treat gun related deaths as we do every other public health menace?