Everyone is missing a big point here. A teacher is not likely to be faced with the possibility of shooting a “known” individual. The reality is that most of the benefit will accrue to schools which are no longer designated gun-free.
Liberals have never, under any circumstances, understood the value of deterrence. These are the same folks who, during the cold war, saw out nuclear arsenal as a threat, TO US!
Liberals think they want total control. They know the people must be unarmed for that to happen. In the end those who end up in control are not who they thought it would be.