an armed society is a polite society... that is the long and short of it...
Rules of engagement (ROE) in any situation (either deployed into a hostile environment or not) clearly specify the right to defend one's self, employing a proportional response to the threat.
This applies (IMHO) to a civilian population as well as an military expeditionand whether you are at home or deployed.
As a soldier, I have the right to return fire in my own defense and can fire pre-emptively if I have gave concern about my or my subordinates' safety.
As a private citizen, I have a Concealed weapons permit. I apply the same ROE here and follow the applicable civilian regulations ie. no weapons in bars, etc.
Bottom line, I shall at all time defend myself, my family and my neighborhood if a threat is posed.