There is much debate considering the carrying of guns (concealed) to protect pupils from intruders. This was indeed bad advice for teachers to carry weapons.
A school is for teaching pupils in mathematics, science, language, and social studies, among other curriculum areas. Teachers are trained to be professional teachers, not policemen. The job of teachers is to motivate, assist pupils to see purpose in learning, and develop interest in the ongoing lessons and units of study. This is what teachers were trained for in teacher preparation colleges and not to serve as a policeman.
The attitude of the teacher is to encourage pupils, develop respect within learners, and help in making pupils empathetic and resourceful. If teachers carry concealed weapons they will need a lot of training and there can always be cross firing of a mishandled weapon. The attitude of the policeman is quite different. He/she emphasizes law and order and not the gentleness that school and society want. Let us have teachers prepare pupils in being ready for College, the work place and civic life within an an improved society.
— Dr. Marlow Ediger, North Newton