In the wake of the slaying of Trayvon Martin, an unarmed 17-year-old, by concealed handgun-permit holder and self-appointed neighborhood watch “captain” George Zimmerman, there has been widespread outrage over permissive gun laws that allow armed residents to act as judge, jury and executioner. Much of this criticism has been directed at Florida’s “stand your ground” law, which has raised questions about when use of deadly force is justifiable in a legal and a moral sense.

The law eliminates an individual’s duty to retreat from a public confrontation when he can safely do so. It also allows shooters to meet nonlethal aggression with lethal force. This means that individuals engaged in fights or scuffles can legally escalate the violence to the point of homicide. When they do, “kill at will” laws provide immunity from criminal prosecution and civil action (i.e., lawsuits). Previously, the duty-to-retreat requirement created a bright-line rule to evaluate the validity of the force used by an individual claiming self-defense. This requirement was based on history and human experience, from the Book of Exodus right through English Common Law and into origins of the American legal system. It was bedrock law in most states until recently.

The experiment started in the Sunshine State. At the urging of the National Rifle Association, Florida enacted the first “kill at will” law. It has been an unmitigated disaster. “Justifiable” homicides have increased from 43 when the law was enacted in 2005 to 105 in 2009. A 2010 St. Petersburg Times review found the “stand your ground” defense invoked in at least 93 Florida cases involving 65 deaths.

Tragically, Trayvon is not the first unarmed teenager to be killed by a shooter using “stand your ground” defense. Florida barely noticed in November 2010 when Carlos Mustelier, 18, was shot four times (including two times in the back) and killed for punching a man he knew in the face. No arrest, no charges.

No wonder law enforcement and prosecutors have complained about this law. The NRA — aided by the American Legislative Exchange Council — has brought the law to 24 other states, including Georgia. With hundreds of years of legal precedent upended, the waters have grown far murkier. With no requirement to retreat, the self-serving testimony of the shooter — particularly when there are no additional eyewitnesses — is often all that is needed to invoke immunity from prosecution and litigation. Every religious and ethical doctrine tells us that if an individual can spare human life, he should. “Kill at will” gives individuals with little or no training and questionable judgment the ability to play vigilante.

The “Kill at Will” law is a dangerous experiment that the Georgia Legislature should repeal as soon as possible.

Josh Horwitz is executive director of the Coalition to Stop Gun Violence.