Data from other states with stand-your-ground laws indicate that the Zimmerman jury was not alone in being sympathetic to such a claim. Whites are significantly more successful claiming self-defense when their attacker is black than blacks are when fighting back against an attacker who is white, according to one study.
To some, such findings are a consequence of the pandemic of violence plaguing elements of the black community. But to others, they suggest that stand-your-ground laws have allowed perceptions of the black community – sometimes accurate, sometimes not – to become a legal justification for using deadly force.
Stand-your-ground laws have begun to change the calculus of self-defense in the United States. The idea behind them is to "expand the legal justification for the use of lethal force in self-defense, thereby lowering the expected cost of using lethal force and increasing the expected cost of committing violent crime," say researchers Cheng Cheng and Mark Hoekstra in a Texas A&M study.
Statistics included in the study bore that out, showing that justifiable homicides rose by 8 percent in stand-your-ground states, amounting to some 600 additional killings.
The laws have spread quickly. Since Florida passed the first stand-your-ground law in 2005, at least 30 other states have followed suit, either though legislative action or court decisions.
This comes at a time when concealed-carry gun laws are being expanded, meaning the success or failure of stand-your-ground laws will depend on "whether [people believe] guns produce a net social benefit or not," says Brannon Denning, a law professor at Samford University in Birmingham, Ala., and author of "Gun Control and Gun Rights: A Reader and Guide."