So we hear about these reports of people getting jumped by a group of other people and the bystanders just watching. Is it lawful to draw your weapon and tell the perpetrators to stop, put their hands up etc? What if it was just one person? How far are we allowed to go in the defense of another?
In a state that recognizes one's lawful authority to determine reasonableness (most states) of threat, and in which one truly believes one's life is at risk of loss, I'd say that's your answer: yes, absolutely.
Of course, the sticky part of it is human nature. The "reasonable man" standard means you get to determine at the time, but others get to judge your actions based on what
they believe a reasonable person would do in the same circumstances. Plus, you might well face a nasty DA who's pushing for notches on the belt (career-wise), or get a DA who's getting heavy pressure elsewhere to jump on you despite the evidence (a la the recent Z trial).
As well, whether it's deemed reasonable might well depend not on what you knew at the time, but what others believe they appreciate would be the case. IOW, they might well deem a "group" to not inherently be a problem, whereas you might well feel you're simply not up to what that particular group was bringing. Or, they might not believe it's reasonable to use lethal force on someone who just clocked you while the "group" stands by watching, whereas were there and saw "the group's" demeanor, eyes, manifest intent to harm shining through their every pore.
Good advice, above: know your state statutes, cold; know your DA and political environment in your community, with respect to how tolerant of SD they all are; and know that in any situation you're going to be questioned as to whether your actions were justifiable if others are downed and you're still standing.
