Necessary and Justified; are they the same?

This arose from the previous conversation, and I'm quite startled to find that some of my friends seem to think they are, at least one way. I think we'd all agree that something can be justified without being necessary; if a courtier sends to tell me my beard is not well cut, I may be justified in responding with at least the quip modest ("Yeah? Well, you suck, so there."*), but I don't have to.

But can something be necessary without being justified? Is it possible to have no alternative but to do something you know is wrong, and which continues to be wrong even after you've done it?

I'd say it is, but I could be wrong. Certainly my attitude would lead to incapacitating guilt, if I were ever in that position, and so I'd be a lot comfier if I could say "oh well, it was the only thing I could do, so I was obviously right to do it." But given the human brain's capacity for sophistry, I would then never be able to trust my feelings again on what is right and what is wrong. Necessity is, at best, a perception; justification is, or is as near as we morally malleable humans can get to, an absolute.

I've never understood why so many people seem to admire Dirty Harry. They would say he does what's necessary, to cleanse the streets of the criminals who always seem to be able to buck the system, and of course in the fictional world the writers create for him he's always right...but the real world doesn't work like that.

In the case of murder and self-defence, having never experienced either, I have no real qualifications, and I mean no disparagement of any kind to anyone who has been in that situation and done what they felt was necessary. Certainly I would prefer that they continue to live rather than the person who, not being in mortal danger themselves, saw no sufficient reason not to kill them. Same with rape and assault: if the choice is killing the other person or being raped, and there are no other alternatives, then yes, it's necessary, and the question of justification is not for me to decide or pontificate about.

But here we get into questions of offence and defence, two more concepts that are often conflated. A gun is not a weapon of defence. A shield is, or a bulletproof vest, or in extremis one's brain, if it works well enough, but a gun is a weapon of making a hole in the other person, and while it may be true that the best defence is a good offence, what a good offence is, above anything else, is basically an offence. And in the field of armed combat, we're basically hopeless at defence, because we have this idea that striking back (or striking first) is more important than not being hit in the first place.

So should we all be trucking around in full armour? Are those people right who say that if a woman gets attacked it's her own fault for not hiring a pack of bodyguards or staying home at night? No, of course they're not. The wrong of the attack outweighs anything done in self-defence. The wrong of the attack needs to be ended, and whatever is done to end it is necessary. And this is where I writhe on the horn, because my gut feeling will not go away...the feeling that if I were in that position, if I were attacked, or saw my loved ones endangered, and did what was necessary, I should never know peaceful sleep again, nor should I deserve or wish to. I guess it's just a good thing that not many people have that. And a fantastically good thing that I am blessed enough to live in a country where the worst of weapons are firmly regulated.

But this is a whole other can of worms, and I have stuff to do that needs doing, so that's it for the moment.

*Hey, Shakespeare I'm not.