[The Saucepan Man]

Phantom, I still take the view that the Wyatt Earp analogy is off, but that's not really the issue here.

If one considers the "diversion" strategy (as helpfully highlighted by Legorli in the film) against Aragorn's decapitation of the Mouth, it seems to me clear that the former is a legitimate wartime tactic while the latter is cold-blooded murder (however evil the murderee).

To convert these incidents into modern day analogies, I am sure that we would all agree that it is perfectly acceptable for an outnumbered army to draw the attention of the enemy force while covert spies behind enemy lines attempts to destroy the enemy's headquarters. But I am not sure that many would agree that it is acceptable to summarily execute a non-combatant emissary of the enemy, and that is precisely what film Aragorn did. If the MoS had obtained information that could endanger Frodo's mission, then it might have been acceptable to take him out, although I would say only only if his capture was not possible or feasible. But the MoS had no such information. Letting him go would have made their situation no worse than it was already.

And I am not sure that the fact that the enemy is inherently and totally evil should make any difference. If an Orc attempted to surrender to Aragorn on the field of battle, would you consider Aragorn justified in killing him nevertheless?