Introduction

Burdens of Proof in Criminal Trials

Introduction

Every criminal trial ends in a decision made under uncertainty, so the law has to say in advance who bears the loss when the evidence leaves the jurors unsure. The criminal system puts that loss on the prosecution. Jurors who believe the accused probably committed the crime, or who think guilt is possible but cannot say it has been proven, must vote to acquit, and that result is the design working as intended. The Model Penal Code states the rule in two parts: no person may be convicted of an offense unless each element is proved beyond a reasonable doubt, and where that proof is missing, the innocence of the defendant is assumed.¹ The second part supplies the reason for the first. Because innocence is the assumed starting point, the prosecution must carry the jury away from it, and a jury that cannot be carried all the way is left with the assumption intact. The demanding standard also reduces the risk that a conviction rests on factual error, which is why it reinforces the presumption of innocence.²

The phrase "beyond a reasonable doubt" appears nowhere in the constitutional text, and the standard was a long-established feature of American law well before it became a constitutional command.³ That change came with In re Winship, decided in 1970, where the Court held that the Due Process Clause requires the prosecution to prove every element of a criminal offense beyond a reasonable doubt in all criminal cases, including juvenile delinquency proceedings based on criminal acts.⁴ The move from established practice to constitutional rule matters because a practice can be relaxed by an ordinary legislative or judicial choice, while a constitutional rule sets a floor that every state must respect. The floor is a high one. Proof beyond a reasonable doubt is the most demanding standard the law uses, and it requires more certainty than either clear and convincing evidence or a preponderance of the evidence.⁵

Winship establishes that the standard exists and that the Constitution enforces it, but it leaves three questions that this chapter takes up in turn. The first is how much proof the prosecution needs, which asks what the standard demands of a jury and how a court may describe it. The second is which facts the prosecution must prove to that standard, a question that depends on what counts as an element of the offense. The third is who may be made to carry the burden on everything else, such as a defense the accused raises or a fact the legislature has placed outside the definition of the crime, and the Code's provisions on defenses, non-element facts, and presumptions bear on that question.⁶ Answering the third question requires separating two kinds of burden, the burden of producing evidence and the burden of persuading the factfinder, and that distinction is developed after the Winship material. The Winship holding itself comes first, because every later rule is measured against it.