http://www.ncsl.org/research/civil-and-criminal-justice/self-defense-and-stand-your-ground.aspx

Self Defense and “Stand Your Ground”

The common law principle of “castle doctrine” says that individuals have the right to use reasonable force, including deadly force, to protect themselves against an intruder in their home. This principle has been codified and expanded by state legislatures.

In the 1980s, a handful of state laws (nicknamed “make my day” laws) addressed immunity from prosecution in use of deadly force against another who unlawfully and forcibly enters a person’s residence. In 2005, Florida passed a law related to castle doctrine, expanding on that premise with “stand your ground” language related to self-defense and duty to retreat. Florida’s law states “a person who is not engaged in an unlawful activity and who is attacked in any other place where he or she has a right to be has no duty to retreat and has the right to stand his or her ground and meet force with force, including deadly force, if he or she reasonably believes it is necessary to do so to prevent death or great bodily harm to himself or herself or another or to prevent the commission of a forcible felony.”