Tim Lynch explains that stand-your-ground laws are an important protection for crime victims but are not a license to provoke a fight and then kill the other person without repercussion.
With respect to incidents outside the home, the Stand Your Ground statutes clarify the law for innocent persons by dispensing with any legal obligation to retreat, hence the name, "Stand Your Ground." What has been overlooked is the fact that the statute only applies to a person under "attack." Again, the rationale is that it is bad enough for an innocent person to find himself under attack by a criminal, but to then have to worry about whether the law requires a retreat is simply too much to ask. As Justice Oliver Wendell Holmes once observed, "detached reflection cannot be demanded in the presence of an uplifted knife." The Florida law says that if you are under attack, retreat if you like, but be assured that you may also stand your ground and fight back if that seems to be the best option. ...
When Zimmerman made the fateful decision to disregard the police dispatcher's statement to await the arrival of the police and not to follow his "suspect," he was acting outside and beyond the Stand Your Ground law. Other legal principles enter the picture and those principles run against Zimmerman. By following Martin, Zimmerman's actions set up the perilous confrontation. Consequently, he will likely be seen as an aggressor in the eyes of the law. Even if Martin threw the first punch, that punch will likely be considered the result of Zimmerman's provocation. Since Martin was unarmed, a gunshot in response to non-deadly force (fisticuffs) will probably be deemed beyond the bounds of normal self-defense. (The Florida legal system will have to consider all of the available evidence and ultimately determine Zimmerman's legal responsibility.)
I don't know what facts will be presented to a jury, but I bet this will be a complicated case for them to work out. If Zimmerman provoked the fight and then shot Martin when when Zimmerman started losing, then the shooting was not self-defense. But Martin might also have been in the wrong if his actions escalated from self-defense to delivering a beating to a prone/pinned Zimmerman. There's no reason why both men can't be guilty.