In order to prevent the mass killing of more people we should make murder illegal, make it illegal to take a gun on to school campus, and make it illegal for someone with a mental illness to purchase a weapon.
If this sounds redundant, it's because it is. All of these are obviously already illegal. Point in fact; the monster at Sandy Hook was denied when he tried to purchase a weapon which forced him to murder his mother and steal her weapons.
It is also noteworthy that CT has an "assault weapons ban". It did nothing to prevent this tragedy. A federal ban would be just as ineffective, redundant, and ridiculous.
Undermining and eroding the Constitution to attack the rights of others will insure that it is not there when your rights need protection from the tyranny of the majority.