The fact of the matter is... we are not in total control of everything in life and can NEVER stop someone intent on killing others that is willing to die to achieve their goal.
This is just a sad fact of life.
I got into that discussion with an anti-gun nut once, and to make the point I asked her “If I or anyone else decided to kill you by walking up and jamming a screwdriver through your neck, what would stop us?” The light went on for her just a little bit.
Nothing makes me angrier than hearing some jackass politician say, “we have to find a way to make sure this never happens again.”
You can’t, you are not God, much as you would like to be, Mr. or Mizz Politician. If you in fact wish to safeguard children, then discuss improving security protocols that are obviously lacking as they pertain to schools, otherwise I am going to know that you mean not to protect them but to use crimes committed against them to advance your agenda against law abiding citizens.