Children are impressionable  Allowing teachers to carry arms in school could mean that very young children could easily become acclimatised to the idea that carrying a gun and ultimately gun usage is ok. Surely the way to prevent incidents like Columbine from happening is to teach children about the potentially destructive and fatal consequences of gun usage? For elementary/primary school-age children, it would be difficult to separate the idea that it’s ok for teachers to always carry guns but not for anyone else.