"If the teachers had a guns too, there couldn't be any school shootings."

[Smith_3]

or "If all responsible citizens carried, there could be no spree killers."

I wonder if those statements are really true. Is gun violence really lower in areas that have lacks gun laws. What do the statistics show? Are there any statistically relevant numbers of cases were a "determined armed citizen saved the day"? I mean there are perhaps individual cases, but what is the overall trend? Do lacks gun laws lead to more or to less innocents getting shot? Or are perhaps other factors more relevant?

I really have my doubts that teachers with guns would be able to stop determined school shooters. If anything, the lacks gun laws would lead to the shooters aquiring larger caliber automatic weapons and targeting the teachers first, no? I doubt that even a large group of teachers with pistols could stop a group of home trained counter-strike kids with AK47s.

Perhaps armed security guards at schools would work, provided they are trained well enough to tell a real threat from a schoolyard brawl.

edit: so could it be perhaps, that the real determining factors are mental healthcare, proper education for everyone and elimination of poverty?