Although there were arguments to be made in favor of treating "serious bodily injury" as a sentencing factor, the rule that statutes should be construed to avoid constitutional difficulties counseled in favor of treating it as an element of the crime. In "Mullaney v. Wilbur", , the Court had held that a state could not define murder so as to require the defendant to affirmatively prove that he had acted in the heat of passion, so as to reduce the crime to manslaughter. In light of the "centuries-old common law recognition of malice as the fact distinguishing murder from manslaughter" and of the "widely held modern view that heat of passion, once raised by the evidence, was a subject of the State's burden," due process required the state to bear the burden of proving absence of heat of passion. Otherwise, the state could "manipulate its way out" of the requirement that it prove every element of the crime beyond a reasonable doubt.