After seeing this I thought about each of the teachers I had from 1st grade through getting a degree in college. There were only four of them that I though had enough common sense that I'd want them carrying to "protect me". None that I'm aware of had any gun handling skills.
And what keeps a teacher from going nuts and shooting up the classroom? The worst school massacre in US history was committed by a member of the school board of the school he blew up with multiple bombs.
http://www.migunowners.org/forum/showthread.php?p=192163
Armed teachers woiuld not have stopped that.
In my opinion at least for colleges allowing students and teaches who have had appropriate training and have obtained permits to carry makes sense, though it won't stop all incidents. Mass murder won't necessarily be stopped even if all of the potential victims are armed. As with the case in 1927 the murderer wanted to commit suicide and take a bunch of people with him. That's hard to stop. Being insane doensn't mean a person is stupid. Someone intent on mass murder can find a way.
An undesirable side effect of the Texas law will be to make the teacher the first target if a crazed murderer enters a classroom, whether they're carrying or not. I doubt that will help teacher recruitment.
There is a cost to having a free society where citizens aern't restrained from peaceful activities because they might do shomething evil but are approprately punishing when they do commit evil. That's how our Federal government was set up, but it's degraded over the years by pllacing more and more restrictions on everyone. On rare occasions that cost is high because someone just doesn't care if they're punished or even die when they commit evil. Is it worth that cost to have a free society? I believe it is.