You don’t have to arm every teacher: just arm one, but don’t tell anyone who it is!
I disagree with the ‘arming of one teacher’ and then not telling anyone who it is. The reality is there are always going to be suicidal people and we never know where they will strike. To that end, more people need to be armed to repel that strike when and where it happens.
Schools are unlike airplanes were an single Air Marshall can effectively cover the entire space because it is enclosed and small. School campuses are entirely too large. In the event in Texas, I understand there were armed guards on campus and they engaged the shooter leaving one officer critically wounded. However, as the saying goes, when seconds count, the police are minutes away.
JoMa