Not an easy solution
I have major issues with the blaming of mental illness for these shootings. I have been a psych nurse most of my adult life, and notice that for the most part, the mentally ill are VICTIMS, they are not perpetrators. They frequently use easily obtained guns to hurt themselves. The prisons are full of people who would like to blame their crimes on "mental illness". And, when they claim that in front of a judge, the examination shows that they know right from wrong, knew what they were doing was wrong, but did it anyway. Or, did it because they knew it was wrong.
Looked up reports from Australia, how they handled mass shootings. Interesting, they followed one guy and the best info was that he wanted to become famous. He was counting up how many people he killed, was it more than the last killer!?! In response, Australia did not use his name in newspapers (or used it very little). They started a "buyback" program for guns. There's some other things they did, too. Cant remember all of it. As a result, gun crimes and suicide by guns are down to considerably.
Its easy to blame the NRA, mental illness, the law etc. In reality, its a complex issue, needing complex solutions.
Also, I have one son who is a teacher. The thought of him carrying a gun to school scares the %#&($*!)(@Z$Y* out of me.
~Sandee~