President Trump says one solution to school shootings is to allow teachers to be armed.

He was mocked for that, but John Stossel says it’s a reasonable idea. Hundreds of schools already allow it.

Keene Independent School District in Texas embraces the idea. Its superintendent, Ricky Stephens, tells Stossel: “We know our staff and our teachers are gonna go [to a shooting] — do we want them to go with a pencil or go with a pistol?”

People worry armed teachers will do more harm than good, but Stossel could find only one case of harm to a student. One teacher mistakenly shot at the ceiling and a student was slightly injured by falling debris.

On the other hand, armed teachers have stopped school shootings. An assistant principal held a school shooter at gunpoint until police arrived.

Teachers at Keene saw how, during the Florida school shooting, the security guard waited outside. “It made me mad,” says one teacher who brings a gun to school. “We have to have a fighting chance if something should happen!”

Keene’s program goes further than Stossel would. Instead of just letting teachers with concealed-carry permits bring their weapons to school, Keene buys selected teachers guns and pays them a $50 monthly bonus for carrying. The school also requires those teachers to get 80 hours of training, and then 40 hours each year after that.

Stossel says at least Keene’s policy is less expensive than what his hometown does. New York City pays 5,000 police officers to patrol city schools.