She is one of Washington's most distinguished judges, writing more than 825 opinions in the 20 years since she became the first woman to sit on the U.S. Court of Appeals for the District of Columbia Circuit. Now Patricia M. Wald is moving to a new arena as a judge on the International Criminal Tribunal, where she will try people accused of committing war crimes in the former Yugoslavia.

"It was something I cared about, something I wanted to do," said Wald, who formally becomes one of 14 judges on the U.N. war crimes court this week. "The timing was right. I've had 20 years here. I felt it was important."

The tribunal, headquartered in The Hague, was established by the U.N. Security Council in 1993 to investigate charges of genocide, crimes against humanity and other offenses committed during recent wars in Croatia, Bosnia and Kosovo. Eight people have been convicted so far, and 32 others are in custody and awaiting trial. Dozens of others have been indicted publicly but not arrested, including Yugoslav President Slobodan Milosevic.

Wald, 71, succeeds Gabrielle Kirk McDonald as the U.S. representative on the court. She has a longstanding interest in international law and has made numerous visits to Eastern Europe in recent years in programs sponsored by the American Bar Association, the State Department and the U.S. Information Agency.

The two-year assignment, made by U.N. Secretary-General Kofi Annan at the State Department's urging, is the latest step in a remarkable career that has included turns as a juvenile justice advocate, a public-interest lawyer, an assistant attorney general and an appeals court judge. President Clinton tried to recruit Wald as his first attorney general in 1993, but she quickly took herself out of the running, saying she wanted to remain a judge.

"She's fast and she's very smart. Everyone with whom she has worked would say that about her," said Harry T. Edwards, chief judge of the D.C. Circuit. "This is the kind of person who is such a star. She could have been standoffish, and played the Washington 'I am a star' role. Instead, she was always approachable and always cared that we got the work done."

Edwards said he waged a titanic struggle recently to persuade Wald to attend a small dinner in her honor. Wald's reaction was "typical of her time on the court--she never has been a person to seek acclaim," he said.

The D.C. Circuit has enormous influence because of the unique blend of cases it gets, largely because of its location in Washington. The court is called upon to resolve disputes over federal regulations that affect everyday life, ruling on issues involving civil rights, the environment, utilities, communications, health care and other weighty subjects. That's in addition to hearing the usual mix of appeals of criminal and civil cases and handling issues that arise from various independent counsel investigations. Just Friday, the court ruled, in an opinion written by Wald, that the Nuclear Regulatory Commission unfairly ignored opponents of the Calvert Cliffs nuclear plant as it rushed to renew the facility's license.

Many scholars consider the court the second most powerful in the nation after the U.S. Supreme Court. Indeed, three of Wald's former colleagues are on the Supreme Court: Antonin Scalia, Clarence Thomas and Ruth Bader Ginsburg.

A Connecticut native and graduate of Yale Law School, Wald came to Washington in 1952 and joined the law firm of Arnold & Porter. Her husband, Robert, also is a lawyer. Patricia Wald took nearly a decade off to raise her five children then began working in the 1960s on issues such as bail reform, juvenile justice and mental health. After joining the staff of Neighborhood Legal Services, she began appearing regularly in courts at a time when women weren't readily accepted by men who had dominated the field.

In the late 1960s, when Wald once identified herself in federal court as "Patricia Wald," she was admonished by the judge, who said that wasn't her "real name." The judge asked Wald if she was married and demanded she restate her name as "Mrs. Robert Wald."

"Fortunately, I feel safe in saying that couldn't happen any more, which goes to show we have made some progress," Wald said. Not only did the judge demean Wald that day, he also dismissed her case concerning the treatment of a mental patient at St. Elizabeths Hospital. Wald later recast the matter as part of a class-action lawsuit and won an even bigger decision.

Wald wouldn't identify the judge, saying only that he's deceased.

She later worked for the Center for Law and Social Policy and the Mental Health Law Project before joining the Justice Department in 1977 as assistant attorney general for legislative affairs. President Jimmy Carter named her to the appeals court in 1979. Seven years later, she became the first woman to serve a regular term as chief judge of a federal appellate court.

Senior U.S. District Judge Aubrey E. Robinson Jr., who was chief judge of that court at the time, recalled he and Wald worked together on issues concerning the management of the courthouse building. Wald also initiated a study to determine if gender bias entered into the courts and found reforms were needed in the treatment of female lawyers.

Wald, chief judge until 1991, said she has seen the appellate court shift from a decidedly liberal tilt in her early years to a sharply conservative bent in the mid-1980s to being closer to the middle these days. Of the court's 11 judges, five were appointed by Democratic presidents and six by Republicans. Wald's departure gives the court a 6-to-4 split, although judges do not always vote along party lines. No replacement has been named.

On a court traditionally loaded with strong personalities and ideologies, Wald said she attempted to remain focused on her work over the years, even during a period when arguments among judges became quite contentious. Of the current court, she said: "We're not in any high state of battle. . . . Sometimes people feel very intensely about substantive matters, but there are no personal vendettas. That has not always been true in the past."

Because cases are randomly assigned to three-judge panels, they can wind up before jurists who have widely divergent views. Some of her best writing came in cases in which she wrote dissents, Wald said. Dissenting opinions, she explained, can persuade judges in other circuits, who are not bound by D.C. Circuit opinions, and can generate interest by the Supreme Court.

One of those instances involved a D.C. law that banned demonstrations within 500 feet of embassies. In 1986, a majority on the appellate court, led by then-Judge Robert H. Bork, upheld the law's ban on signs and the limits it placed on numbers of demonstrators. In her 48-page dissent, Wald said that Bork was "too willing . . . to sacrifice First Amendment freedoms" and argued the law was unconstitutional. The Supreme Court agreed with her.

Wald's departure leaves the D.C. Circuit with only one Carter appointee: the current chief judge, Edwards, who joined the court in 1980.

Paying tribute to Wald at the recent dinner, Edwards told his colleagues: "She is a brilliant lawyer and jurist, she is lightning fast in her work, she has an incredible memory. She misses no nuance in an argument; she is an extraordinary and tenacious advocate of a position once she has analyzed competing arguments. She is fair-minded, and she is gracious on the bench."

Edwards said Wald caught lawyers off guard during oral arguments by summing up issues in a gracious but challenging manner. In a legendary episode, an attorney once "passed out cold" in front of Wald as she addressed him, Edwards said, adding, "The deputy marshal thought that Judge Wald had killed the attorney with her polite questions."

On the tribunal, Wald likely will sit on one of three panels that tries cases. Each panel has three judges. The tribunal's remaining five judges are assigned to hear appeals. It is the first tribunal to prosecute war crimes since the Nuremberg and Tokyo trials after World War II. A similar tribunal has been formed to prosecute those responsible for the massacre in Rwanda in 1994.

Wald said her experience on the appellate bench should smooth matters in the transition because in both courts judges must be impartial, look at all sides fairly, ensure they have legal authority and find legitimate ways to compromise. Still, she acknowledged, the work ahead is daunting.

"I've been trying to read as much as I can," Wald said. "It's a new set of laws, a new set of procedures, a new set of colleagues and a new country."

CAPTION: Patricia M. Wald, of Washington, has been named to a U.N. tribunal: "It was something I cared about."

CAPTION: A fellow judge describes Wald as a "brilliant lawyer and jurist . . . lightning fast in her work."