"Is it permitted for any reason directly and deliberately and intentionally to kill an innocent human being?"
The adjectives and adverbs are really important here. To examine the variations:
(Examples: a deadly aggressor in a criminal or wartime situation, or a person justly convicted of a capital crime. Answer: under some conditions, yes.)
(Examples: performing a hysterectomy on a pregnant woman who has uterine cancer, even though the baby is not yet capable of survival outside of the womb. Bombing a Hamas rocket-launcher site even though it's on the roof of a family residence. Obliterating the military and industrial and port facilities of Hamburg during WWII, even though the resultant firestorm will foreseeably spread to civilian areas. Answer: under some conditions, yes.)
(Examples: Aborting a handicapped baby. Killing prisoners of war who have surrendered and have been disarmed. Killing everyone in a city indiscriminately. Answer: no.)
One last question: does it sometimes happen that the situation is complex and changing rapidly, you're not sure of the facts, the options are all dreadful, and you have to make a quick decision under extreme pressure? I'm sure that happens. We must try not to kill the innocent. May God have mercy on us all.
Trying to work through this carefully. What say ye?
I think you’re trying to put too fine a point on it.
It sounds like you’re interpreting your question to mean “is it ever OK to kill an innocent person for no reason at all”. But that’s no dilemma. You make the question too easy. That’s cheating. :-)
For me the important word is still “any”. Can there be *any* reason? Yes, there can be circumstances where it is ~necessary~ to make a decision to kill an “innocent” person. Directly. Deliberately. Intentionally.
If it is necessary, that makes it permissible. Otherwise there’s nothing to be decided. Then the question becomes: What makes it necessary? What is a good enough reason?
IMHO: Stopping a war and avoiding a catastrophic invasion is a good enough reason.