The argument that there are too many whack jobs that carry guns and are more likely to cause problems than to end a problem ignores the many, many incidents in which an armed citizen does end bad situations before it gets worse. To say that only extremely trained people- like cops

- should carry guns, is silly.
I was a cop in the small town of Granger, Wyoming where the nearest l.e. help was twenty minutes away. I was grateful for the armed populace that I knew would back me up if I needed it.
A lady in Texas was in a "gun free" zone. A restaurant when a nut with a gun entered and killed her parents. Her legally owned firearm was in the car. Could she have ended the situation? Quite possibly. A distracted gunman trying to focus on a large group of people while one of those people decide to take an aimed practiced shot from behind concealment? At the very worst, if she'd been shot by the badguy, at least she would have died trying to do the right thing.