The New Yorker's John Lee Anderson gives a very compelling account of the difficult anti-opium efforts deep in Taliban country. He also, I think, explains in an indirect way why we've managed to turn the anti-Taliban efforts from mop-up (which is what it was when I lived in there in 2002-3) to a suddenly very losable war.
The problem, ultimately, is cultural. The last graf of the piece:
Back at camp, everyone was in a bad mood. Hook, the former prison guard, remarked, “We ought to take all those guys and hang them in public, beginning with the governor.” He laughed, and added, “Good thing I’m not an idealist—I’m just here for the money.”