One only needs to Google Israeli terrorist attacks foiled by armed Israeli citizens to find out how many, and how often an armed populations is able to defend itself against those wanting to kill them. Kinda like at FT. Hood, or the Navy Yard, or ............
To me the best one was the school down in GA. Right after the hearings for Sandy Hook. When one of the teachers said there was no way someone with a gun could've stopped Adam Lanza. The GA incident went down, like the guy showed his gun, the person carrying (I believe it was the vice-principle) drew and fired, killing the perp. End of story, no one else killed. As soon as that blew over and proved the teacher from Sandy Hook WRONG, the story went right straight out of the media.
Someone might fact check me on this, because I know I read it. But, I can't find it. It just went "POOF!" right out of the news....