In the wake of the most recent school shooting, the argument has been made that if we just armed everyone with a gun, preventive shootings would prevent mass shootings. If one guys shoots the crazy person who is about to shoot a bunch of other people, the pending tragedy would be averted and everyone lives a happy life.
Of course, this simply raises the question of how does one determine which crazy person to shoot to prevent the next gun-created massacre? We're not quite at the Minority Report point in society, so precognition is out. However, this argument assumes that non-crazy people are able to divine the insanity level of others and thus judge whether or not to kill someone based on... Magic, maybe?
As a country, we're becoming used to the idea of acting before evidence is proven out. We went to war in a country for over a decade and sacrificed many lives on a hunch that they might use weapons we considered off limits. We've accepted that all of our communications are probably being read and analyzed by our government, and we submit to embarrassing invasions of privacy just to travel to visit our families for the holidays.
Thought: if we as a country don't care about our myriad privacy rights or the rights of other countries to self-govern, why should our opinions be accepted concerning whether we're allowed to own a weapon of minor to moderate destruction?