Fair Play?

It's said that fighting should be 'fair', and that you never shoot a man in the back.

While this is possibly noble and just, it's also sometimes just flat out wrong, as when the righteous Judge Roy Bean eliminated the evil Bad Bob:

 Robert, it is written that thou shalt not impugn the integrity of Miss Lily Langtry.

End of lesson.

Or when a U. S. Green Beret took the initiative to neutralize a threat before the enemy killed more friendlies or American soldiers. He has now been charged with murder.

When evil men are your enemies, you do what needs to be done.