Burden of Proof

In 1970 the U.S. Supreme Court declared that the Constitution required the reasonable doubt rule in criminal cases. In the case of In re Winship, 397 U.S. 358 (1970), the Court held that the "Due Process Clause protects the accused against conviction except upon proof beyond a reasonable doubt of every fact necessary to constitute the crime with which he is charged" (p. 364).

Winship restated the general understanding of the rule governing proof in a criminal case, and therefore it was not especially controversial. At the same time, however, by articulating a constitutional basis for the rule, Winship laid the foundation for litigation over the proper scope of this newly articulated constitutional rule.

One question is whether the rule applies in contexts that are not criminal prosecutions, but are similar in some respects to criminal cases. Winship itself extended the rule from ordinary criminal cases to certain types of juvenile delinquency proceedings. In general, the Court has declined to hold that the rule is required in noncriminal proceedings, although it has held that sometimes the Constitution requires the government to prove its case by the intermediate standard of "clear and convincing evidence." For example, the state must prevail by clear and convincing evidence in proceedings for compulsory psychiatric hospitalization (Addington v. Texas, 441 U.S. 418 (1979)) and in proceedings to terminate parental rights (Santosky v. Kramer, 455 U.S. 745 (1982)).

A second controversial question is whether the rule applies to every issue in a criminal case, or whether particular issues may be excluded from the rule. Although most states have long adhered to the general rule that the prosecution must prove guilt beyond a reasonable doubt, each state also has developed its own idiosyncratic list of exceptions, requiring defendants to prove such issues as self-defense, duress, insanity, entrapment, renunciation, and mistake.

State criminal codes frequently use the term defense or affirmative defense to describe an issue where the burden of proof is assigned to the defendant. Other codes simply state that the burden of proof for all issues is on the state except where the statute expressly states otherwise.

Both the reasonable doubt rule and some of its exceptions have relatively ancient roots. The reasonable doubt rule has been recognized in Anglo-American law at least since 1798, and probably for several centuries before that (May; Morano; Green). Exceptions to the rule were also apparently recognized in the eighteenth and nineteenth centuries (Fletcher). But not until the rule acquired constitutional standing in 1970 did courts begin to seek criteria to govern its application, and the search has not been an easy one.

In a pair of very similar cases decided soon after Winship, the Court reached virtually opposite conclusions. Both cases involved statutes that shifted to the defendant the burden of proving that the crime was not murder but only the less serious crime of manslaughter. In Mullaney v. Wilbur, 421 U.S. 684 (1975), the Court had invalidated a state statute requiring the defendant to prove provocation, but two years later, in Patterson v. New York, 432 U.S. 197 (1977), the Court, without overruling Mullaney, upheld a statute requiring the defendant to prove "extreme emotional disturbance." The Court found a critical distinction in the way the two statutes were written: the Mullaney statute defined murder as including the absence of provocation, while the Patterson statute defined murder without reference to extreme emotional disturbance, which it defined separately as a defense. The Court seemingly gave states considerable leeway to make drafting choices that would determine which facts constitute elements of a crime, and must therefore be proved beyond a reasonable doubt.

In the following decade, the Court said little more about when the reasonable doubt rule applied. In the few cases it did decide, the Court favored the approach it took in Patterson, giving considerable leeway to the states in this regard. In Martin v. Ohio, 480 U.S. 228 (1987), for instance, the Court held that even though the defendant would have been entirely innocent of murder if her claim of self-defense were true, the state could require her to prove she had acted in self-defense because the state had not defined murder as including the absence of self-defense.

The rule's scope became controversial again, however, as legislatures increasingly began to draft statutes that specified particular sentencing factors, and courts began to consider whether such factors should be governed by the reasonable doubt rule. A sentencing factor is a fact that determines not what crime a defendant committed, but what sentence the defendant can receive. For example, drug laws frequently dictate that the sentence for possessing or selling drugs shall be increased by a certain number of years as the quantity possessed increases. A sentencing factor also may take the form of a "mandatory minimum," which means that if the factor is present, the defendant must serve at least a specified number of years, greater than the minimum sentence otherwise prescribed for the crime. A sentencing factor, therefore, may be of critical importance in determining how many years a defendant will serve in prison.

While the idea that certain facts, like possessing large quantities of drugs, should lead to harsher sentences is not particularly controversial, the procedure for determining those facts has become quite controversial. Statutes commonly provide that sentencing factors are determined at a sentencing hearing by a judge using a "preponderance of the evidence" standard. In McMillan v. Pennsylvania, 477 U.S. 79 (1986), the Court upheld a statute authorizing a judge to impose a mandatory minimum five-year sentence if the judge found by a preponderance of the evidence that the defendant had possessed a firearm during the commission of a criminal offense. By the late 1990s, however, members of the Supreme Court began voicing concern that sentencing factors were in effect circumventing the protections of the reasonable doubt rule. In 2000, the issue reached a constitutional boiling point in Apprendi v. New Jersey, 120 S. Ct. 2348 (2000).

In Apprendi, the defendant had fired shots into the home of an African-American family that had recently moved into an all-white neighborhood. A state statute provided that using a firearm to shoot into a home would ordinarily carry a sentencing range of five to ten years, but that if the crime was motivated by racial bias, the sentencing range rose to ten to twenty years. Despite Apprendi's denial at the sentencing hearing that he had acted out of racial bias, a judge found by a preponderance of the evidence that Apprendi had been so motivated and sentenced him to twelve years—two more years than the maximum sentence of ten years he could have received if the judge had not found the sentencing factor to be present.

The Supreme Court held that because Apprendi received a sentence that was greater than the maximum sentence he otherwise could have received without the sentencing enhancement, due process required that the sentencing factor of racial bias be proven to a jury beyond a reasonable doubt. But the Apprendi case does not necessarily apply the reasonable doubt rule to every sentencing factor that increases a defendant's punishment; the Court declined to disturb an earlier decision holding that when a defendant's prior convictions are used to increase his maximum sentence, the prior crimes need not be proved to a jury beyond a reasonable doubt (Almendarez-Torres v. United States, 523 U.S. 224 (1998)), and it also implied that when aggravating factors are required before the death penalty can be imposed, the aggravating factors need not be proved to a jury beyond a reasonable doubt. The scope of the rule in this area remains unclear, including whether the reasonable doubt rule applies to sentencing factors that increase the defendant's punishment within the statutory range, but do not increase the maximum punishment authorized by statute. Because sentencing factors are so widely used to calculate sentences, the answer to this question is crucial to the future of sentencing in the United States.

The courts are likely to struggle in the coming years with this question and other situations involving the reasonable doubt rule. In resolving such questions, it is useful to consider the rule's purposes.