Asked what he thinks might prevent shootings: "Nothing," he said. "At the end of the day, there are no preventable measures. It's human nature."
He suspects the violence he witnessed as a child made him an "angry kid." He says it may have factored into his shooting. Harless grew up in a rough part of a small town hear Baltimore. Another child beat him with a lead pipe when he was 7. He said he watched his drunk father beat his mother regularly.
That made him protective of the people he liked. He said that might have been what made him run across the cafeteria with a gun when he saw McCoy scuffling with administrators.
If his father had gotten the support for his drinking, if his mother had felt there was enough of a safety net (financial and social) to leave her abusive husband, if they had had a good enough job to move out of the bad part of town, if there had been some sort of repercussion for the beating he got when he was 7 (or if the kid who had given him the beating had had child welfare support in his own life), none of this may have happened.
A vulnerable mind can be reached and calmed through many things. There are many things that could have prevented Harness' actions, and the shooting at Sandy Hook. I firmly believe that.