Today Florida Gov. Rick Scott is appointing a task force to examine his state's self-defense law in light of the Trayvon Martin case. Meanwhile, the American Legislative Exchange Council, partly in response to the controversy sparked by George Zimmerman's shooting of Martin, says it will no longer promote "stand your ground" laws like Florida's or get involved in other noneconomic debates. The Wall Street Journal reports that "attempts to pass such laws in Alaska and Iowa were halted after Mr. Martin was killed," adding that "Stand Your Ground opponents are counting on a backlash against the self-defense laws to strengthen their hand in legislative talks." What is the nature of this "backlash," and does it make any sense? Critics tend to conflate several different features of Florida's law, the most prominent of which—the right to "stand your ground"—has nothing to do with Zimmerman's defense as it has been explained so far.

When they amended Florida's self-defense law in 2005, state legislators eliminated the "duty to retreat" for a person attacked in a public place who "reasonably believes" deadly force "is necessary to prevent imminent death or great bodily harm to himself or herself or another or to prevent the imminent commission of a forcible felony." Contrary to New York Mayor Michael Bloomberg, that does not mean people "make their own decisions as to whether someone is threatening or not" and therefore have "a license to murder," since the judgment has to be reasonable, meaning someone who uses deadly force has to show it was justified by the circumstances. In any case, as I've said before, this change does not seem relevant to Zimmerman's defense, since he would have had no opportunity to safely retreat in the circumstances he describes. It might still be true that the right to "stand your ground" and "meet force with force" sometimes encourages an unnecessary escalation of violence or enables guilty people to escape punishment, as critics of the law claim. But to make that case, they must do more than cite increases in the number of justifiable homicides, which you would expect to see even if the law were working exactly as intended. The crucial question is whether these homicides should be deemed justified. 

Right after the law was changed, Brooklyn Law School professor Anthony Sebok argued that establishing a right to stand your ground in public places would have little impact:

Florida is now joining the large number of states who do not value "life" above the right to stand unmolested wherever one wants. It's unlikely, however, that this change will change outcomes in particular cases.

Previously, all Lisa [the defendant] had to do to win her case was argue that she honestly and reasonably believed that she could not retreat safely. Now, she has to argue, instead—somewhat similarly—that she reasonably believed that if she didn't use deadly force, Bob [her attacker] imminently would.

Under either standard, Lisa still has the burden of proof to justify her killing. Also, under either standard, the jury may disbelieve her if there are witnesses around to contradict her story.

Sebok was more troubled by another change: the presumption that anyone who "unlawfully and forcefully" enters someone else's home or vehicle is intent on violence, thereby automatically justifying the use of deadly force. Under the old law, by contrast, "a person who killed someone in their home had the burden of proof to show that they were in fear for their safety." Sebok argued that the new standard attached too little value to human life and could lead to "serious miscarriages of justice." But again, this change played no role in the fight that ended with Trayvon Martin's death.

Two other changes are more relevant to the case against George Zimmerman. Florida's law requires that police have probable cause to believe not only that a homicide was committed but that it was not justified by self-defense. That requirement (which is the same as the standard applied to all other crimes) may have delayed Zimmerman's arrest, although the blame more likely lies with an inadequate investigation. The law, as interpreted by the Florida Supreme Court, also gives Zimmerman a right to a pretrial evidentiary hearing where he can try to convince Judge Kenneth Lester that he acted in self-defense. The standard at the hearing is a "preponderance of the evidence," meaning it is more likely than not that Zimmerman's use of force was justified. If he can meet that burden, he won't go to trial, but if he could meet that burden he would be acquitted in any case*, since the prosecution has to prove the homicide was unlawful beyond a reasonable doubt.

There is room for reasonable people to disagree about the fairness and practical impact of all these provisions. But the Trayvon Martin case has no bearing on the first two, and it hardly counts as a conclusive argument against the second two. Assuming he goes to trial, Zimmerman may be convicted (probably of manslaughter, rather than the second-degree murder charge brought by special prosecutor Angela Corey) and sentenced to prison. Or he may be acquitted if the prosecution does not do a good enough job of refuting his self-defense claim. At the trial stage, Northern Kentucky University law professor Michael J.Z. Mannheimer notes, the same rules apply "in virtually every state." Thus it is hard to see how the outcome of this case, no matter what it is, will tell us whether other states should imitate Florida's self-defense law.

Addendum: Here is a Wisconsin case that may illustrate the "miscarriages of justice" that Sebok worried could result from a reinforced Castle Doctrine: An angry neighbor breaks up a loud party, and the underage drinkers attending it scatter. One teenager, Bo Morrison, makes the fatal mistake of hiding in the neighbor's enclosed porch. The neighbor, Adam Kind, shoots and kills Morrison, then successfully argues that he was defending his home and his family from an intruder. Kind may have genuinely feared for his family's safety, but the fact that he provoked Morrison's flight by violently breaking up a party on someone else's property, kicking in a garage door after police were unsuccessful in gaining entrance, makes him somewhat less sympathetic. Discuss.

[*changed the wording a bit for clarification]