Believe it or not, even some of us "common folk" can identify a person who may be endangering the lives of us or our families, and be trusted to defend ourselves. As it were, most criminals prefer their victims unarmed, and they won't wait for the police to arrive. Most of the general public can be trained in the use of their firearms.
Hmmm. I can see your point but I have to disagree. You say that "common folk" can identify a person who may be endangering the lives of others. Therefore you accept that if the general public are placed with the same responsibility with regard to weapons, there will always be those who will abuse that responsibility.
With that in mind, it is my opinion that the responsibility for the use of lethal weapons should remain with those enforcing the law and I'll go back to my previous statement where I said that the general public should not be trusted. Unfortunately the US is in a bit of a difficult position here, having already accepted a long period of time where the general public are trusted with weapons. This means that guns are widespread, and obviously it would be a tough job indeed to take them off the streets. But you have to start somewhere, and I think most people would agree that the US has a gun crime problem, caused mainly by the fact that weapons are widespread and the laws against carrying them are not tough enough.