Anyway, his new TV show 'Justified' seems to be simply a weekly dramatisation of this very premise. I've only seen one episode, but it appears to be about a (present day) sheriff who puts himself into situations where he is legally 'Justified' in killing someone. The clue is in the name. It is a little like Dexter, as the victims are bad guys, and the lawman's a psycho, but obviously the killing is occurring in the public sphere.
I think the premise is quite promising, but the first episode was a bit disappointing. It could get much better, as his colleagues and friends sort of figure out he is a violent lunatic, but at present it's rather tame.
This and Luther, also last week, are I think spin-offs by writers who love Deadwood and The Wire, and have tried to extract some of the magical essence of these two shows for mass consumption. This isn't just parasitism, I think, it is a genuine homage to quality - like using Nessun Dorma for football, or putting Shakespeare into Doctor Who. If something is wonderful, but hard to access, can some of its power be opened up via a more accessible and simplified form.
Unfortunately I think neither show has quite managed it. They seem too safe. I think in trying to simplify and make accessible they have somehow lost the essence they are trying to convey. I respect the writers for figuring out the jewel - for example the violence inside the man - and trying to replicate it. I hope both shows find their feet and succeed, not least because I like both actors, but they haven't quite made it yet.