Ahead of America's costliest-ever elections, Raphael Rowe investigates how powerful lobby groups helped create laws blamed for one of the most controversial killings in recent US history. The shooting dead of a 17-year-old teenager by a neighbourhood watchman polarised America, provoked presidential intervention and shone a light on an extreme American law, called "Stand Your Ground." It provides immunity from prosecution or, as some say, a "License to Kill". But does gun politics also show how America really works? Panorama asks: is American democracy for sale?
