Concept
Sufficiency of the Evidence
Burdens of proof and persuasion
Sufficiency of the Evidence
The last section showed that a presumption cannot do the prosecution's proving for it. A related question arises even when no presumption is involved: whether the evidence the prosecution actually offered is enough to let a conviction stand. The Due Process Clause requires the prosecution to establish every element of the offense beyond a reasonable doubt, a rule the Court announced in In re Winship.1 That requirement works at two stages. Jurors apply it when they deliberate, and judges apply it when they decide whether the evidence could support a guilty verdict at all, both before the case goes to the jury and after the verdict.2 The parts below take up the judge's test, the difference between how the law treats acquittals and convictions, and the role of circumstantial evidence.
The Judge's Test
The prosecution carries a burden of production on every element. It must come forward with evidence on which a reasonable jury could conclude that each element has been established beyond a reasonable doubt, and if it does not, the court must enter a judgment of acquittal.3 The threshold the judge applies mirrors the standard the jury applies. In a civil case the judge need only be able to say that some reasonable juror could find the fact by a preponderance of the evidence, and in a criminal case the same logic raises the bar, so the question becomes whether some reasonable juror could find the fact beyond a reasonable doubt.4 If the reasonable-doubt standard governed only what jurors felt in the jury room, nothing would stop a jury from convicting on proof that no reasonable person could accept. Judicial review of sufficiency closes that gap.
The point was once contested in the lower courts. Until 1972 the Second Circuit treated the standard as merely descriptive of the state of mind required of the factfinder, and not of the quantum and quality of proof needed to support a conviction, so a judge ruling on a motion for acquittal in a jury trial did not distinguish between civil and criminal cases.5 That court then overruled its earlier position, relying partly on Winship, and adopted a directed-verdict criterion under which the judge must require acquittal if reasonable jurors must necessarily have a reasonable doubt about guilt.6 In Jackson v. Virginia the Supreme Court described that criterion as now prevailing in federal criminal trials and described the sufficiency standard it announced as the constitutional minimum needed to enforce the due process right recognized in Winship.7
Jackson's formulation asks whether, after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt.8 The review applies when a defendant seeks a directed verdict before the case goes to the jury, when the defendant challenges the verdict afterward, and on appeal.9 In a state prosecution the same question is one of federal due process, so a conviction that no rational judge or jury could have returned violates the Constitution. Evidence law adds one further floor: a conviction cannot rest entirely on an uncorroborated extrajudicial confession, so when the defendant does not admit guilt in court, the prosecution must offer extrinsic evidence that at least tends to establish the confession's trustworthiness. Viewing the evidence favorably to the prosecution reflects the division of labor at trial, since the jury alone determines credibility, resolves conflicts in testimony, and draws reasonable inferences, and the judge therefore does not reweigh the proof.10 On an exam, the common error is to ask whether the judge finds the defendant guilty, when the test asks what any rational trier of fact could find.
In federal court the test is raised through a motion for judgment of acquittal under Federal Rule of Criminal Procedure 29, which directs the court to enter an acquittal on any offense for which the evidence is insufficient to sustain a conviction.11 Later sections treat the timing and mechanics of that motion. The same gatekeeping idea is easy to see in a civil setting. A shopper who slips on a fresh banana peel in a supermarket aisle and proves nothing more has not shown how long the peel lay there, so a jury could not reasonably infer that the store's inspections were negligent, and the court should grant a directed verdict without requiring the store to put on any evidence.12 That result does not mean the store was careful; it means the evidence does not permit a reasonable inference either way. The criminal version of the inquiry is the same, with the threshold set at reasonable doubt instead of a preponderance.
Acquittals and Convictions
The sufficiency check runs in one direction only. A factfinder in a criminal case has traditionally been allowed to return a not-guilty verdict that is unreasonable but unassailable, which follows from the rule that an acquittal cannot be appealed even when the evidence of guilt is overwhelming.13 The power to err on the side of mercy, however, has never been thought to include a power to return an unreasonable guilty verdict, and the settled practice of testing sufficiency through a motion for judgment of acquittal and a postverdict appeal confirms it.14 The two rules rest on different reasons. An acquittal ends the prosecution and exposes no one to punishment, so the law tolerates an occasional mistaken acquittal rather than reopen it. A conviction costs the defendant liberty, so the law must be able to ask whether it rests on evidence a reasonable person could accept. None of this means that convictions are often reversed on sufficiency grounds, because the standard leaves the jury wide room.15
The judge's own power runs in the same direction. Because the defendant has a right to trial by jury, the prosecution cannot obtain a peremptory ruling on the elements of the offense, so the court may direct an acquittal for a failure of proof but may not direct a conviction because the proof is strong.16 This is the production-side counterpart of the rule from the last section that a verdict may not be directed against a criminal defendant.17 Strong evidence therefore sends the case to the jury and does not end it.
Circumstantial Evidence
Circumstantial evidence alone can establish every element of a crime, and no greater degree of certainty is required of it than of direct evidence.18 The circumstances must be such that, on the whole, the trier of fact may find each element beyond a reasonable doubt, but the defendant is not entitled to an instruction that circumstantial evidence must exclude every reasonable hypothesis other than guilt.19 Holland v. United States, a decision cited in Jackson, rejected that very contention.20 The reason is that the reasonable-doubt standard measures how firmly the factfinder must be convinced and does not rank kinds of proof. An eyewitness can be mistaken or lying, while a chain of circumstances can leave no sensible doubt, so a rule requiring circumstantial proof to eliminate every other hypothesis would impose a stricter standard on one kind of proof than the standard itself demands.
Circumstantial proof must still reach each element. Securities prosecutions show both sides of that point. Evidence that a trader knew material nonpublic information is often in the trader's own control, so enforcers frequently have no choice but to build the case from circumstances.21 Yet at least one court, in a securities enforcement action, has held that suspicious trading by itself does not support an inference that the trader possessed the information, because that inference would excuse the enforcer from identifying the information, proving its materiality, and proving possession and use.22
Both scenes involve the same crime and the same kind of evidence. What moves the answer is whether the circumstances, taken together, connect the defendant to the offense strongly enough that a rational juror could find identity beyond a reasonable doubt.