Money Makes the World Go Round
Carson Wells is a bounty hunter hired by a bunch of high-rolling American drug dealers to kill Anton Chigurh. Sound like dream come true? Well, in the words of one character, Wells has led a "charmed life." The guy was a colonel during the Vietnam War and now he's a private mercenary willing to do anything his employer wants if the price is right.
We know from this little background that money is Wells's main motivator, and we see it in action when he tries to make a deal with Llewellyn Moss for the stolen drug money, saying, "Look, you gotta give me this money. I have no other reason to protect you."
Violent by Nature, or Naturally Violent?
Wells also seems to have a really, really laidback attitude toward the shocking violence he sees every day. When asked his opinion of Anton Chigurh, he answers, "Yeah, he's a psychopathic killer. But so what? There's plenty of them around."
In fact, in some ways, we can compare the two: they're both cold-hearted killers with a lust for money and an almost inhuman way of looking at the world. Unlike Chigurh, though, Wells is a reasonable guy with understandable motivations (like money). When Chigurh is about to kill Wells, Wells says to him, "Do you have any idea how crazy you are?"
He offers to give Chigurh the money, but Chigurh, in the end, doesn't care about wealth: he cares about his own wacky form of justice. In this case, "justice" means that Chigurh has to kill Wells, since Wells is supposed to kill him. In the end, even money is no match for psychotic genius.