THE principle that in criminal trials prosecutors must prove their cases beyond a reasonable doubt is ingrained in most Americans. It is well known to anyone who has had the privilege of applying that standard as a juror.
Tuesday's United States Supreme Court decision affirming the principle, however, shows that even this basic tenet must not be taken for granted. That the court unanimously reaffirmed the principle is heartening; that it needed to is not.
The ruling came in a Louisiana murder case. A jury convicted defendant John Sullivan after the judge instructed the panel that, to convict, there must be left no "substantial basis" for reasonable doubt that "would give rise to a grave uncertainty" about Sullivan's guilt. The judge used these terms despite a high-court decision three years ago that held such wording unconstitutional for failing to clearly state the true burden of proof. Sullivan appealed his conviction to the Louisiana Supreme Court, whi ch upheld it, saying that the mistake was harmless given the trial's evidence.
Sullivan then appealed to the US Supreme Court. Writing for the court, Justice Antonin Scalia held that a jury's understanding of the state's burden of proof is so critical that without it "a criminal trial cannot reliably serve its function." The trial judge's mistake, therefore, was not harmless. Sullivan's conviction was overturned.
In a concurring opinion, Chief Justice William Rehnquist noted the evolving doctrine of harmless error and said he doubted whether improper instructions on reasonable doubt should be viewed as "a breed apart." We don't doubt it; the principle should be viewed that way. Tuesday's ruling also should reinforce with judges the need for clear, accurate instructions to ensure a fair trial.