Terrorists will never again find docile passengers.
Yes. And due to increasingly popular "shall issue" concealed carry licenses, there is an improved chance that a terrorist might be stopped dead by an armed American.
Unfortunately, our schools remain "gun free zones", for the most part, and there is little reason to believe that terrorists could not storm a school, collect the students and staff in a single location, and arrange an outcome little different from what happened in Russia.
Our teachers have a duty to arm themselves with assault rifles or invite armed citizens into their classrooms in order to repel an attack immediately.