You have the bolded backwards. The first describes the subjective component (actual provocation); the second is the objective component (the reasonable person standard). I'm not trying to be nitpicky, I just want to make sure we're talking about this correctly.
Edit: to be more explicit, it should read:
But the irrational state contemplated by the law is a state of high passion. Seriously. Without that, there is no provocation defense, and in your formulation of the facts, absent that he would be guilty of murder. (I.e., the planning ahead bit.)
I know the standard, and you have it incorrect. I think it would just be economic for me to say this - if the guy walks into court and says "I acted rationally, 10/10 would shoot again," the statute is explicitly written for him to fail the second element. Under your standard, the court would respond with "yeah, but a reasonable person in your situation as YOU would have perceived it differently." That's not subjective.
I'll respond to both of you, since it's all pretty much the same thing.
I just grabbed this from Westlaw (State v. Rambo, N.J.Super.A.D.2008, 951 A.2d 1075):
Passion/provocation manslaughter has four elements, which are (1) the provocation must be adequate, (2) the defendant must not have had time to cool off between the provocation and the slaying, (3) the provocation must have actually impassioned the defendant, and (4) the defendant must not have actually cooled off before the slaying; the first two elements are objective, i.e., they are viewed from the perspective of a reasonable person, while the last two elements are subjective, i.e., whether the defendant was actually impassioned and whether the defendant actually did cool off before committing the fatal act.
So I was too strong (read: wrong) in saying he didn't have to actually be impassioned; he does. But I was right that whether the provocation is adequate is the only point where we determine causation. We don't need to determine that the impassioned state is what caused the killing. We just need to determine that he was adequately provoked to an impassioned state, and that he hadn't had time to cool off.
MIMIC talked about adequate provocation a couple pages ago.
I could be wrong, feel free to show me case law that says the impassioned state must have caused the irrational action. But as far as I've seen, it's only required to show that they were "under the influence" of an impassioned state.
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EDIT: Let me clarify what I mean with an analogy. You walk in on your wife, sleeping with another man. You're so enraged you throw her stuff out the window and kick her out. Now you're on trial for kicking her out. If later on in an interview, you say, "Man, kicking her out was the best thing I ever did," that's not going to change the fact that you were provoked to an impassioned state, and the provocation caused your action. Now, if a jury decides you didn't have the right to kick her out, but they think you were impassioned when you did so, your interview isn't going to hurt your impassioned state defense.