sentences:  Ultimately, there was no reason to believe that in this case Congress had abandoned any of the models it had previously employed.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.