By WILLIAM GLABERSON The role of the American jury, the central vehicle for citizen participation in the legal system, is being sharply limited by new laws, court rulings and a legal culture that is moving away from trials as a method of resolving disputes. .... "We as a society have to decide: Do we want to have our justice system essentially run by experts -- lawyers and judges -- or do we want to retain a role for the jury?" said Valerie P. Hans, an expert on juries who is a professor at the University of Delaware.

Increased plea bargaining, tort-reform laws limiting jury awards, and Supreme Court rulings giving judges new power to screen the evidence presented to jurors are among many forces marginalizing the role of the jury, some lawyers and judges argue.

Court statistics show, for example, that jury trials are a rapidly shrinking part of federal court caseloads , with only 4.3 percent of federal criminal charges now ending in jury verdicts, down from 10.4 percent in 1988. The number of federal civil cases resolved by juries has also dropped, to 1.5 percent from 5.4 percent in 1962.

And those awards that civil juries do make are being overturned with greater frequency. Federal appeals courts are reversing certain types of civil jury awards twice as often as they did a few years ago. ....

Although jury trials in modern times have long accounted for a small part of the legal caseload, judges and other experts on the courts say the diminishing role of the jury in state and federal courts reflects rapidly changing attitudes about how much power jurors ought to have. The judicial system's commitment to the jury as an institution, they argue, is being tested as never before.

"Why have a jury at all?" one former juror, Michael McCarthy asked bitterly in an interview.

Mr. McCarthy said he and his fellow jurors were outraged in December when a Houston judge told them that Texas' tort-reform law would require a reduction of more than $100 million in an award they had given the family of a pipefitter killed in an industrial accident at a Phillips Petroleum plastics plant in 1999.

The worker, Juan Martinez Jr., died when highly volatile chemicals exploded in a 500-degree fireball. The jury concluded that the accident had resulted from lax safety measures at the complex, which had experienced three explosions over 12 years, including one that killed 23 workers and injured 132 others in 1989.

Not everyone is critical of the trend limiting the role of juries. Some legal scholars, judges and business lawyers say that reining in juries is a necessity in an overloaded legal system. Others argue that juries must be controlled to limit excesses, and curb prejudices like hostility to big corporations.

"Not every legal rule that constrains a jury's discretion is an attack on the jury system," said David F. Levi, a federal district judge in Sacramento. "It may be a limit on raw power, but that may be what we need to have a fair system."

Among appeals judges, the growing skepticism of juries is reflected by their increasing willingness to overturn verdicts. In an analysis prepared for this article, Kevin M. Clermont and Theodore Eisenberg, law professors at Cornell University, found that federal appeals courts reversed civil jury awards in injury and contract cases less than 20 percent of the time in 1987. Over the next decade, reversals rose to nearly 40 percent.

For those jurors who do decide cases, the experience can be mystifying. It can also be embittering.

Last spring, Tyrone N. Neal, a retired government printing worker, served on a case in which a young man had lost a leg because, he claimed, of improper care in a Maryland hospital. The jury Mr. Neal was on awarded the man $5.4 million. When he learned during an interview that a judge had reduced the award to $515,000, Mr. Neal was disturbed. "It's like a slap in the face," he said. " 'We get your opinion and then we just go decide it our way.' " Mr. McCarthy, the Houston juror, said his panel had concluded that only a big verdict would protect workers by showing the managers at Phillips Petroleum that there was a large cost associated with the repeated worker deaths. The award was $117 million, including $110 million in punitive damages, which Phillips' lawyers argued was excessive. They also said the complex was making strenuous efforts to improve safety for its workers.

The judge told the jurors it would almost certainly be cut to $11 million under Texas laws that sharply limit punitive damages. "I felt betrayed," Mr. McCarthy said. "You think you've done a good service to the community and then you find out all your work has come to nothing." ....

Last spring, John E. Babiarz Jr., a Superior Court judge in Delaware who headed a state jury study, made a speech proposing that the use of civil juries be sharply curtailed. "It is simply impossible," Judge Babiarz said, "to achieve fairness when each case is decided by a different group of 12 people who are called to serve on a civil jury perhaps only once in their lives."

In a new survey of 594 federal trial judges nationally, 27.4 percent said juries should decide fewer types of cases. The survey, conducted by The Dallas Morning News and the Southern Methodist University School of Law, is to be published this spring in the school's law review. Some scholars argue that appeals judges are now substituting their own opinions for those of jurors. ....

.... [T]he Supreme Court itself has done as much as any court in the country to accelerate the trend. In two major rulings in 1993 and 1999, the justices directed trial judges to screen technical and scientific testimony before it gets to jurors.

The limits on juries are being instituted not only by courts but also by Congress and state legislatures. In a series of articles last spring, The Dallas Morning News found that, often through legislation, 41 states imposed some limits on the types of cases juries could hear. Included are rules banning jury trials dealing with issues like consumer fraud and suits over adverse reactions to vaccines.

Some judges say jury trials are a shrinking part of the legal system because lawyers distrust them. They ask for jury trials less often and, in turn, lose their ability to argue before ordinary people.

"You have a bar that is increasingly lacking in jury skills, and they distrust juries so they stay away from them," said Judge Patrick E. Higgenbotham of the United States Court of Appeals for the Fifth Circuit, which hears cases from Louisiana, Mississippi and Texas.

In the Maryland hospital case, two of the jurors said in interviews, the jury spent considerable time trying to find an amount that would compensate Gilford V. Tyler Jr., the man who had lost his leg as a result, the jury found, of the hospital's negligence. A spokeswoman for the hospital, Prince George's Hospital Center, said Mr. Tyler had appropriate care.

The judge, Thomas P. Smith of Circuit Court in Prince George's County, agreed that the jury's verdict had been fairer than the reduction to the $515,000 the hospital's lawyers demanded.

"The thought that the injuries sustained by plaintiff are in any way compensated by $515,000," the judge said in a hearing, was "abhorrent."

But in January he ruled that Maryland law required him to reduce the jury award to the lower amount. Mr. Tyler's lawyers are appealing to Maryland's highest court, claiming the law is unconstitutional.

In the meantime, the jurors who heard Mr. Tyler's case are wondering whether the legal system values the work they did. "In one sense," said Elizabeth Pearson, a retired postal worker who was on the jury, "it does seem like a waste of time."