Some country that has it figured out, does not just arm teachers, they arm students.
The best way to combat evil intent, is with greater force. Bringing a handgun to a handgun fight would not be as effective as bringing a well trained marksman with a rifle to a handgun fight.
Is it possible, having access to locked down rifles in schools, by well trained marksman / school personnel, would be a better idea, than having a gym teacher, packing a gun in his gym shorts?
On a ship in the military, all arms are locked away, and distributed at an appropriate time, as the use of force is called for.
IMHO, control over the school, should be in the hands of the personel in the school, but what steps we take to achieve that end, is something we need to put lots of thought into.
I would like to read a paper on the security of Swiss schools.
edit: those are likely not semi auto rifles on the girls backs.