Florida's Stand Your Ground law, is it a good idea, or an invitation to legalized murder?

Under Jeb Bush and intense pressure from NRA lobbyist Marion Hammer, Florida GOPers passed the ill-conceived Stand Your Ground law. It’s not just Florida where this is the law. The GOP has rammed this legislation through in 21 states to date. It’s like a return to Tombstone Arizona circa 1881 and the gunfight at the OK Coral. The Stand Your Ground law allowed neighborhood watch captain George Zimmerman, a serial 911 caller, to gun down an unarmed 17 year old boy, Trayvon Martin. Martin was acting in a highly threatening manner, armed as he was with a pack of Skittles and some iced tea. Not only that, he was black in a predominantly white neighborhood. Reason enough to kill him first and ask questions later, right?

What are the Stand Your Ground rules? Is it OK to shoot anybody you don’t like, so long as you say after they are dead and unable to tell their side of the story that you felt threatened by them? Or do they have to be black in a predominantly white neighborhood? Does their armament have to be Skittles, or will any candy do? Please educate me, because it strikes me that if you can shoot people of any race, the Stand Your Ground laws could be a great tool for electioneering. The first political party to heavily arm themselves and murder all their opposition will win the next election. Great idea, right?