"What do you propose to keep the Adam Lanzas of the world from committing atrocities?"

Well, to PREVENT something like this from happening again, people with mental illnesses, who are dangerous, would need to be declared by a judge to be mentally incompetent. That would involve everyone around every person with any mental illness, keeping close tabs on them and their behavior. Then, assuming these people have correct knowledge to work off of, and can remove their own personal biases, then they would report any warning signs to a psychiatrist, who would evaluate this person. Then the psychiatrist would have to decide, again without letting their personal biases and values interfere, if the subject needs to be put in a hospital for treatment. If they don't want to go, then the psychiatrist would have to get a hearing with a judge to compel the person to be institutionalized. This of course also relies on the judge setting aside their personal biases and interpreting the information correctly. If the judge declares them mentally incompetent, then this person is prohibited from owning firearms.

But of course this system would only work perfectly if everyone involved is correct in their assessments and not acting out of vindictiveness or ulterior motives.

And it also relies on the individual who may be having problems to trust other people or authority figures enough to speak to them, show up to appointments, etc. . .

And it would only prevent LEGAL ownership of a gun. There is a black market of illegal guns that criminals and gangsters use. (And it's not Gun Shows) Or this mentally ill person might steal a gun, or they might go and legally buy a gun before they have committed a crime, or before one of their friends reports them to a psychiatrist.

So while that system is being perfected to the point where it doesn’t get abused or infringe on civil liberties, how do we keep school children safe?

The solution is effective, cheap, and could be implemented tomorrow. Allow people with concealed carry permits to be armed in schools.

This is not ‘arming teachers’. This is not hiring security guards, or paying for police officers to be assigned to a school. “But teachers don’t like guns!” Again, this isn’t mandatory, the teachers who don’t like guns shouldn’t carry a gun. But not all teachers or school staff are afraid of guns. There were at least two women at Sandy Hook who stood up to the attacker and lost their lives. If they had a Glock 26 handy, they probably would have shot at the attacker, (even if they aren’t gun people).

Almost universally, the people who commit these crimes end their attack at the first sign of resistance. The guy at Virginia Tech killed himself when he heard the police trying to get in. The guy at Trolley Square fired a couple of shots at Ken Hammond, but retreated into a store when Hammond didn’t back down. The guy in Clackamas Oregon (remember that there was a shooting at a Mall in Oregon recently?) killed himself when he saw Ryan Melis pointing a gun at him.

If it is known that a school, or a school district, or a state allows concealed carry in its schools, then any school shooter seeking fame and lasting notoriety will view that school, district or state as a place where they will likely fail in their demented quest.  Think about it, we can all name the Sandy Hook killer and picture his face. Who knows, off the top of their head, the name of the Clackamas Mall killer?

And if the potential killer ignores that possibility and attacks a school that allows concealed carry, then the attack would be cut short by the one or two people in the school who are legally carrying and have prepared for this unlikely event.

And if the attack never comes, then that concealed carrier’s gun will just sit quietly in its holster, minding its own business.