Patterson (D) became estranged from his wife, Roberta. She resumed an association with John Northrup, a neighbor to whom she had been engaged prior to her marriage to D. On December 27, 1970, D borrowed a rifle from an acquaintance and went to the residence of his father-in-law. He observed his wife through a window in a state of semi-undress in the presence of Northrup. D entered the house and killed Northrup by shooting him twice in the head. D was charged with second-degree murder. In New York, there are two elements of this crime: (1) 'intent to cause the death of another person'; and (2) 'causing the death of such person or a third person.' Malice aforethought is not an element of the crime. The State also permits a defendant to raise an affirmative defense that he 'acted under the influence of extreme emotional disturbance for which there was a reasonable explanation or excuse.' Under state law, a person is guilty of manslaughter if he intentionally kills another person 'under circumstances which do not constitute murder because he acts under the influence of extreme emotional disturbance.' D admitted to killing Northrup but raised the defense of extreme emotional disturbance. The jury was instructed that D had the burden of proving his affirmative defense by a preponderance of the evidence. The jury was told that if it found beyond a reasonable doubt that D had intentionally killed Northrup but that D had demonstrated by a preponderance of the evidence that he had acted under the influence of extreme emotional disturbance, it had to find D guilty of manslaughter instead of murder. D was convicted of second-degree murder. D appealed, and during the appeal, the Supreme Court decided Mullaney v. Wilbur, 421 U.S. 684 (1975), in which the Court declared Maine's murder statute unconstitutional. Under the Maine statute, a person accused of murder could rebut the statutory presumption that he committed the offense with 'malice aforethought' by proving that he acted in the heat of passion on sudden provocation. The Court held that this scheme improperly shifted the burden of persuasion from the prosecutor to the defendant and was, therefore, a violation of due process. D contends the New York statute has the same flaw. The Court of Appeals disagreed because the New York affirmative defense of extreme emotional disturbance bears no direct relationship to any element of murder.