The six Guantanamo detainees whom the U.S. government wants to execute "are, and will remain, innocent unless proved guilty beyond a reasonable doubt," according to the legal adviser to the Pentagon's Office of Military Commissions.

Could anyone in America actually presume Khalid Shaikh Mohammed and his co-conspirators to be innocent? Oops, "alleged co-conspirators." I wish the presumption of innocence did exist in every prosecution, but in most cases it is unlikely, and in high profile cases it is impossible —- a semantic ideal.

The power of semantics was demonstrated by the philosopher Minnie Pearl, whose boyfriend said that she "looked like the first breath of spring. Well, he actually said I looked like the end of a long, hard winter." Similarly, when Judge Hilton Fuller said, "That's their only defense, because everyone in the world knows he did it," it was not the same as saying that Brian Nichols is guilty. Rather, if the jurors believe the delusional compulsion defense, they should find him not guilty.

But, then "not guilty" is not the same as "innocent." Juries do not declare that defendants are innocent.

Before a jury deliberates, the judge will tell them something like this: "The indictment or formal charge against any defendant is not evidence of guilt. Indeed, every defendant is presumed by the law to be innocent. The law does not require a defendant to prove innocence or to produce any evidence at all."

The law may make that presumption, but jurors don't. They know from television that a defendant on trial probably did it. As far back as the mid-1880s one British judge said: "It is greatly to be feared that the so-called presumption of innocence in favor of the prisoner at the bar is a pretence, a delusion, and empty sound. It ought not to be, but it is."

Most defendants plead guilty before trial. A Colorado judge, Morris B. Hoffman, recently wrote: "The ones who take their cases to trial are also overwhelmingly guilty, at least in the sense that there is no issue about whether they committed the charged acts. [Those trials] are about moral guilt, not factual guilt. That is, they are about the level of the defendant's culpability and therefore the level of the crime of which he will be convicted."

Long ago, the U.S. Supreme Court traced the presumption of innocence to the book of Deuteronomy, through Greek and Roman law, and into the English law that came to America. In that 1895 case, Coffin v. U.S., the court pointed out that the presumption of innocence and the standard of proof in a criminal case —- guilt beyond a reasonable doubt —- were often confused.

Even today, after the instruction about the presumption of innocence, the judge says, "The government has the burden of proving a defendant guilty beyond a reasonable doubt, and if it fails to do so you must find that defendant not guilty."

Yale law professor James Q. Whitman points out in his new book, "The Origins of Reasonable Doubt," that this standard of proof was introduced into English law only after trial by ordeal was abandoned. Trial by ordeal, such as burning his flesh or holding him under water, placed the burden on God to decide whether the accused was guilty. If innocent, the wound would heal or the accused would not drown.

After we abandoned trial by ordeal, the "beyond a reasonable doubt" standard of proof ensured that a jury, although exercising godlike power, was less likely to make a mistake.

The remaining problem is whether the jury actually understands the instruction on reasonable doubt, or other instructions, for that matter. Studies show that 30-50 percent of mock jurors do not understand key instructions, partly because they are written in legalese to satisfy appellate courts.

However, the beauty of the jury system is that the collective understanding and intelligence of a jury is quite high. Most juries are conscientious about holding the prosecution to its burden of proof. The small percentage of convicts who are actually innocent are victims of other breakdowns in the system.

The motto of the Georgia Supreme Court is: "Let justice be done though the heavens fall." The treatment of the Guantanamo detainees and the Brian Nichols case illustrate another motto, "Justice delayed is justice denied."

But, if the juries in those cases have the integrity to hold the prosecution to its burden of proof, justice will be done. Eventually.

> Richardson R. Lynn is the dean of Atlanta's John Marshall Law School.