In Michigan, especially now that we have legislative castle doctrine, one does not have to warn the perp prior to shooting. That the perp is in one's home without permission, especially during sleeping hours, is grounds to fire. There is the face-value assumption in Michigan, that the perp intends to cause great bodily harm or death.
Re: the distance, and extent of threat, according to the instructor of our CCW course (27 years service as the director of Oakland County’s S.W.A.T. Team), 43 feet is a credible threat whether someone has a weapon or not. The weapon in hand simply assures you will, for example, be poked if a perp has a knife. Weapon or not, they will, at 43 feet, be able to reach and attack you before expiring if you do not shoot. Ergo, the point we were taught, if a credible threat is made in public, at 43 feet one has grounds to fire. In one's home, one has grounds to fire at face value, on an intruder, especially at night.
To me, the ethical question is not so much the shoot or do not shoot. The ethical question is does one leave the security of their "safe room" to engage the perp in the first place. In my case, I would have to risk engaging, because I have a 12-year-old daughter, and I would have to assure her safety. I could not simply hunker down and wait.
