What is "Stand Your Ground?"
In essence, Florida's "Stand Your Ground" (SYG) law extends the "no duty to retreat" rule to locations outside your home. It means that if you are in a place that you have a right to be, are doing something that you have a right to be doing, and someone else initiates an illegal encounter that puts you at risk, you don't have to retreat — even though that might be the best thing to do. SYG is good law, because it puts the burden where it belongs — on the aggressor.
For the record, George Zimmerman DID NOT invoke "Stand Your Ground", because retreat was impossible in his case; he was pinned to the ground. Therefor, there was no need for him to argue that he didn't need to retreat, because there was no way that he could retreat.
There has been an attempt to compare the 2011 Marissa Alexander case with the Zimmerman case. There is no similarity because the facts in the two cases are substantially different.
It's best to avoid a threat if you can. If you can't avoid the threat, it's second-best to retreat from it if you can. If you can't avoid, or retreat from the threat, it's comforting to know that you have a means of dealing with it, and that the law is on your side.
-fl