The trouble is, there is always some lunatic who will try to kill people with a ploughshare.
As the parent of two beautiful little boys, my heart breaks for those families. Yet, the cold harsh truth is there is no current or future legislation that could have prevented such a senseless act of savagery. Evil is real, and there is no real way to thwart a homicidal killer hellbent on mayhem and destruction. Previous incidents have shown these deranged individuals to be very methodical in planning their attacks. In my opinion, these people would have gone to any lengths to acquire the weapons used in their attacks -- another layer of laws or bans would be inconsequential.
We need to look deeper into the psyche of our own society, from the glorification of violence coming out of Hollywood to the plethora of first-person shooter games that desensitize our youth to the concept of killing. And then we have the media hype that surrounds each incident, where the loner, social-outcast killer gets their 15 (or more) minutes of fame. Everybody recognizes Adam Lanza's name as that of the killer, but how many of us, off the top of our head, could name one child that was murdered that day? If it were up to me, these killers would remain unknown and go to their grave without the media hype and sensationalism that undoubtedly fuels the imagination of the next would-be mass murderer.
As many here discussed, there is no readily available solution to these indiscriminate acts of violence. I wish I had an answer, but I don't. You can't fix crazy.