At her trial for murder of her husband, the trial court admitted evidence that appellant suffered from battered women’s syndrome (BWS) but instructed the jury that self-defense requires an actual and reasonable belief in the necessity of defending against imminent peril. It also instructed the jury that it could not consider the BWS evidence in determining the reasonableness of appellant’s belief in her need to shoot her husband. Although the jury was instructed concerning unreasonable self defense, it was instructed that “imminent peril” was that which is apparent to a reasonable person. In McNeil’s direct appeal, the state court concluded that although the instructions were erroneous, they were harmless. Here, the federal appellate court granted habeas relief. Because the erroneous imperfect self-defense instruction wholly deprived appellant of that defense by requiring that her fear be reasonable, she was denied due process. The instruction prevented the jury from considering her defense that she was guilty of nothing more than voluntary manslaughter, which deprived her of a constitutional right to present a defense.