Due process (14th Amendment), and burden of proving self defense. Note that the charge requires that the state prove prior calculation and design.
Due process and 14th Amendment:
So here, the state has proved the elements of aggravated murder, and instructions are correct, under Winship. As a result, if the affirmative defense is supposed to negative an element of the crime (prior intent and calculation, in this case), it's sort of moot.
The dissent points out that the majority is really assuming a lot about the jury's understanding of burdens. The defendant should not share the risk of non-persuasion, in other words.
The majority view (which WI follows) says there's no duty to retreat, unless the defendant is the agressor. Failure to retreat is a factor the jury can consider, however, when deciding whether the defendant's beliefs were reasonable.
If someone provokes an attack, they're not able to use self-defense as a defense. One who provokes an attack can regain the privilege of self defense if the attack that you provoke could reasonably be thought of as likely to cause death or GBH; also if you withdraw from the fight and give adequate notice.
She was charged with (and convicted of) First Degree Intentional Homicide. She was prevented from presenting evidence of his history of violence (McMorris) evidence. The trial court basically thought that since he was unarmed, it was unlikely that she was in imanent fear of great bodily harm or death.
There were also issues regarding jury instructions.
"Perfect" self defense is generally what we call "self defense."
Generally (§904.04) you can't engage in character assassination by listing prior bad acts. Indeed, you can't introduce this evidence in order to establish that the victim would have been violent in this instance. The exception here is based on the fact that we're establishing the defendant's state of mind, not anything about the victim.
Some other exceptions: absence of mistake (in other words, he always does this), identity (this is his particular modus operandi).
Generally the court would give a "limiting instruction" saying what the evidence in question should be used to determine (i.e., don't use it to form the opinion that Mr. Head was a low-life and the world was better off without him).
Defendant has the burden of production for a self-defense defense (also stated as "defendant bears the risk of non-production:" the evidence could be introduced by the prosecution as part of something else they're trying to show. The state has the burden of persuading, beyond reasonable doubt, that there was no self defense.
Here we see the distinction between perfect and imperfect belief: reasonableness of the belief.
There are mental illnesses that people self-medicate with alcohol (PTSD, for example, or depression), but a lot of the time you don't have the option of defending with mental disease or defect.
Intoxication, as a defensive strategy, is aimed at intent. It's not a defense to recklessness, if you'd have been aware had you been sober.
Interesting irony: you can be too drunk to drive, but plenty sober to understand your rights and waive Miranda protection. :)
Again, we've got trouble with jury instructions, and the court finds that a reasonable juror might be confused.
5th amendment (due process), via 14th amendment (applies to states), plus Winship (state must prove), and Sandstrom (jury instructions can't say to presume an element, or to shift the burden of persuasion). In Patterson, for example, the court said that the state could require the defendant to persuade about the factors of an affirmative defense.
The dissent here wants to focus on the elements of the crime: intoxication doesn't by itself relieve one of guilt, so let's not emphasize it too much-- just ask whether there is reasonable doubt about the element.
"Theory of defense" instruction: notifying the jury that the theory of the defense, if it is believed, is grounds for acquittal.
But the jury could reasonably find that he had intent, so there you have it.
Basically the main thing here is that other evidence can rebut the evidence about intoxication.
Note that this was instigated by a political adversary of the defendant.
There's some commentary on the duties of the counsel. The court wants to give the defendant a pass on this offense, but they word it carefully to avoid possible future situations of collusion between officials. That's what all the "open and unconcealed" stuff is about, along with the "good faith."
So the rare mistake of law can be excused, but the situation is narrowly defined.
This presents a more complex situation, too: the defendant is developmentally a child, in spite of chronological age. The sex was consensual (in a psychological, if not legal sense).
Since the MD statutory rape law defines a strict liability offense, and that would mean the defense of mistake might not help you. Now intent is not the only mental element there is (mens rea can include knowledge). This is a mental issue of knowledge (i.e., of the girl's age). But the statute has no mental element whatsoever, so evidence about his mistake of fact is not relevant or probative of any element at issue in the case.
Ultimately it's about legislative intent: even though mens rea was added into many of the other sex crime statutes at the time of this recodification, it was not in this section. This was strict liability from the get-go.
Note that the necessity defense could cover stuff like arson (we had to burn that one house down to prevent the spread of the wildfire).
This is different from intoxication, which goes to negate the element of intent, and is therefore placed right after the mental status instruction.