This note argues that, in developing the contemporary mandatory-permissive standard, the Supreme Court has misunderstood the effects of presumptions on juries. Presumptions that are ‘permissive’ in theory may nevertheless be ‘mandatory’ in fact, thereby leading some juries to convict regardless of their beliefs and inclinations. Thus, these legal presumptions may undermine the moral sense and political function of the jury.

Part I of this note shows, through doctrinal analysis, that the mandatory-permissive distinction is an anomaly in the Court's jurisprudence. Part II shows that this distinction is at variance with a substantial body of empirical social science research. This part suggests that jurors are influenced significantly by the authority-laden legal structure surrounding judicial instructions on all presumptions—however permissive in theory. Part III proposes that the distinction between ‘mandatory’ and ‘permissive’ presumptions be abandoned, and that ‘reasonable-doubt’ due process scrutiny8 be applied to all presumptions. This proposal would help to prevent the improper use of presumptions and ensure that jury verdicts reflect jurors' actual beliefs.