Story highlights Jeffrey Toobin: Trayvon Martin, 17, was shot dead out buying candy in horrifying case

"Stand your ground" law allows killing if shooter feels "reasonably" threatened, he says

Toobin: Law means alleged shooter's killing is justified by his own perception of threat

Trayvon no longer here to give his side, Toobin says

Trayvon Martin went out to buy some Skittles -- and was shot dead before he made it home. The case is horrifying, maddening, grotesque. And -- perhaps worst of all -- there may be nothing Florida law enforcement can do about it.

As the world now knows, the 17-year-old Martin walked to a store in Orlando to buy some snacks on the night of February 26. George Zimmerman, a volunteer Neighborhood Watch captain, thought the boy looked suspicious and called 911. The 911 operator told Zimmerman to keep his distance -- police would be sent -- but there was a confrontation between Zimmerman and Martin. Martin was killed with a single shot to the chest. Florida authorities have not arrested Zimmerman, and federal authorities recently joined the investigation.

The legal question at the heart of the case involves Florida's so-called "stand your ground" law, which the legislature passed, at the behest of the National Rifle Association, in 2005. Before that time, Florida law resembled that of most other states; during confrontations, individuals had a duty to retreat rather than to respond to provocations. Under the new law, a person is allowed to use deadly force if he is in a place he has a right to be and feels reasonably threatened with serious harm.

In this case, then, the question is whether Zimmerman was in such a place and felt reasonably threatened. The 911 operator told Zimmerman to keep his distance from Martin, but Zimmerman had a right to be on the street. That's where neighborhood watch volunteers work.

Jeffrey Toobin

Clearly, the question at the heart of the case is whether Zimmerman reasonably felt threatened. On this issue, the evidence currently seems murky. There appears to have been some sort of confrontation between Zimmerman and Martin. Police found Zimmerman with an injury to his head. Most important -- and most tragic -- the police will hear only one side of the story about this confrontation. Trayvon is not around to tell his story. The continuing investigation will surely focus on finding other witnesses.

The facts of this case show why the "stand your ground" law is so important. The law focuses on the subjective understanding of the shooter. Was his understanding of the situation "reasonable"? Ultimately, that would be a question for the jury to decide, but it still gives a lot of deference to the perpetrator of a violent act. The new law even allows a disproportionate response; if someone comes at you with a fist, you can reply with a gun.

In light of the shift in the law, it's not surprising that since the law went into effect, reports of justifiable homicides have tripled, according to the Florida Department of Law Enforcement.

JUST WATCHED Why Trayvon's cell records matter Replay More Videos ... MUST WATCH Why Trayvon's cell records matter 00:10

JUST WATCHED Neighbor: Shooting wasn't self defense Replay More Videos ... MUST WATCH Neighbor: Shooting wasn't self defense 02:57

Another case under litigation in Florida highlights the effect of the law. In September 2010, David James was playing basketball with his 8-year-old daughter on an outdoor court in Valrico. A boy was skateboarding on the court at the same time, and Trevor Dooley, a man who lived in the area, told the boy he shouldn't be skateboarding there. James stood up for the boy, and he and Dooley had a confrontation.

Dooley was carrying a gun and wound up shooting James dead. Dooley asserted that he felt threatened by James, and has asked that the case be dismissed before trial under the "stand your ground" law. (The judge will soon make a ruling.)

In both of these cases -- in the deaths of both James and Martin -- the legal defense for the shooters appears to rely almost completely on the "stand your ground" law. In the death of David James, prosecutors are doing their best against tough odds. In the death of Trayvon Martin, it's prosecutors who are taking the heat for failing, thus far, to bring any charges against George Zimmerman.

But this outrage, understandable though it is, might be directed somewhere else as well. The Florida legislators who voted for the "stand your ground" law -- and Gov. Jeb Bush, who signed it -- have something to answer for as well.