Firefly & Ethics in the West

The question of ethics in the West was raised in my mind after watching "The Train Job" and reading the critical piece by Mark Eaton on McCarthy. Eaton notes that "what constitutes ethical behavior in the violent world of the West" is a tenet in McCarthy's novels, including All the Pretty Horses. There are characters in All the Pretty Horses that are rather ambiguous and clouded in terms of what kind of a person they are: the Captain and Pérez are never explicitly pegged by McCarthy as good or evil. Similarly, in "The Train Job," Mal (whose name literally means 'bad' in Latin) has no scruples in completing a heist for a less-than-savory character by shady means; that is, until he finds out that he has been paid to rob badly-needed medicine. Additionally, he is sheltering River, who is being hunted by the Alliance. When he is asked why he took in River and her brother, Simon, Mal shrugs and says "Because it's the right thing to do."
Mal is by no means a do-gooder bent on saving the helpless. He and his crew are amongst the border planets and are just trying to get by, much like John Grady and Rawlins originally set out to do. Like Grady, the crew of Serenity want work. They have no problem accepting a job to steal from a train. As mentioned earlier, the problem arises when ethics come into play. Mal immediately seeks to return the stolen medicine even though he is being paid a hefty sum to steal it. Like the West in Mexico in All the Pretty Horses, the final frontier and the people who inhabit it make their own justice based on their own  sense of ethics and moral qualms. McCarthy never seeks to define what is good or bad because good or bad does not exist in the West. While the Alliance may be initially labelled as the bad guys because of the horrible effects they had on River, that structured government has no real hold over the border planets.