Ultimately, I would have to abide by my bishop's decision.
If your bishop tells you that killing your children isn't murder (perhaps because they are possessed by the devil) then what?
What if there are two conflicting bishops? The whole spiritualist outlook seems like a formula for conflict.
I didn't make myself clear. The natural law is "the first line of defense." Murder is always wrong. So, with regard to the Yeats case, there would be no need for me to seek the counsel of my bishop to determine my course of action. The case with Joan of Arc is different, since the command to undertake a war against England wasn't intrinsically evil. Whether such a course of action was prudent, or commanded by God, would have been difficult to determine.
Parenthetically, the fact of my children's possession is irrelevant. Murder is always wrong.
What if there are two conflicting bishops? The whole spiritualist outlook seems like a formula for conflict.
I am always obligated to act according to my conscience, but I am never permitted to do anything that is intrinsically evil. Since I am obligated to act according to my conscience, I am obligated to inform my conscience as best I can.
Bishops' opinions frequently differ, particularly regarding the prudence of particular courses of action, i.e., the application of principles to particular circumstances. In normal disciplinary matters (not doctrinal matters), I'm obligated to abide by the decision of my bishop, unless his command violates my conscience or the natural law.