I watched No Country for Old Men for the 3rd time so my girlfriend could see it recently. I have never read the original Cormac McCarthy novel. This time though, I suddenly realized all the clues that the organization that has funded the drug sale around which the plot revolves is probably the CIA. The man who hires retired Colonel Carson Wells works in a building with an floor not visible from the street, he has no apparent criminal background, he can even hire a person like Wells anyway, etc.
Apparently this connection is part of the original story, but in the movie is subtle enough I just never noticed it before. Another great detail in a great movie.