These answers clarify things for me. It sounds very much like, according to these standards, Martin would have been justified in shooting Zimmerman?
But Zimmerman is not justified in shooting Martin, because Martin didn't overreact, was reasonable, and because Zimmerman instigated the incident. Is that a good summation of the "Zimmerman's guilty" side?
To make it plain, if someone is following me, harassing or intimidating me, and they reach into a pocket, I have the right to shoot them? (Because I fear they are reaching for a gun and my life is in danger.)
What an interesting worldview that represents.
If the person is entirely unknown to you, then yes, you're justified in hitting that person. I'm not so certain that you would be justified in shooting them, however. I wouldn't be horrified by, say, an involuntary manslaughter charge, if Martin had shot and killed Zimmerman. Also, Martin was 17, so any gun he had would likely be illegally carried. But even so, I also wouldn't be horrified by the shooting.
The thing that Lefty left out is, it's not a matter of being shot in the back, just of the other person being faster than you. Even if the other guy only has a knife, who wants to get stabbed in the back?
In any case, I believe that the person who instigated the fight, should bear the penalties. This is, obviously, not to justify domestic abuse. You can't beat a girlfriend for looking at your cell phone, Chris Brown. But the Australian kid that body-slammed the smaller kid that was punching him? Or Rayon Mcintosh beating those two women that were chasing him with a metal rod? I have no problem with those. And I have no issue with someone who is being chased around, even in the daytime, turning around and punching their pursuer.
It's cute to talk about what you would have done, if you were Martin. The thing is, you really don't know what you would have done. I certainly don't. I may have run home. I may have stopped running once I went around the corner. I may have put my hands up, or I may have punched Zimmerman. You simply can't know how you would respond to a threat, because you would respond differently simply depending on what state of mind you were on.
However, I do know exactly what I would do if I were driving my car, and saw someone walking down the street. I would simply keep driving. I certainly would *not* call the cops, and then jump out of my car and chase the person.