In California, a murder conviction requires a finding of express or implied malice. Express malice requires intent to kill "unlawfully," while implied does not. California Penal Code section 29.4 permits evidence of voluntary intoxication on the issue of whether a defendant "harbored express malice."
At trial, Soto claimed "imperfect" self-defense, which is the actual, but unreasonable, belief that acting in self-defense was necessary. A successful imperfect self-defense claim will result in voluntary manslaughter because "one who holds an honest but unreasonable belief in the necessity to defend against imminent peril to life or great bodily injury does not harbor malice and commits no greater offense than manslaughter."
