Her benchside manner is so stern, her stare so penetrating, that some young lawyers call her "laser eyes."

Her written opinions tick off the law, tick off the precedents and fit in the facts, all without rhetoric or asides. They are the work of a technician, not an ideologue.

In state where ideological extremes flourish, Sandra D. O'Connor has shown a knack for avoiding them throughout her career as a lawyer, state senator and judge. As a politician, she has been on either side of the Equal Rights Amendment and the abortion issue. As a judge, she is described as a tough sentencer, capable of imposing the death penalty.

But as she demonstrated in a 1978 murder case, she is just as capable of wiping out her own sentence and ordering a new trial when she thinks something has gone wrong in the process of criminal justice.

For these reasons, her nomination was endorsed by virtually all those who know her in Arizona, from conservative Sen. Barry Goldwater to the head of the Arizona American Civil Liberties Union. At the same time, the state's lawyers have given her consistently high marks in the bar association's ratings of judges in the state.

And for the same reasons, most lawyers said it would be risky to predict how she might vote on many of the controversial issues that will confront the Supreme Court.

At 51 she is young for a Supreme Court justice, and her term of service could carry her far beyond any of the current skirmishes and into territory as yet untouched by the high court or any other.

A recent law journal article she wrote suggests, however, that in her overall view of the role of the federal judiciary she is well in tune with the Burger Court's efforts to shift much judicial power back to the states.

"It is," she wrote, "a step in the right direction."

O'Connor for 18 months has been one of nine judges on the Arizona Court of Appeals, one step below the state's highest court, the state Supreme Court. She served as a Superior Court judge in Phoenix for five years before that, hearing ordinary criminal and civil cases. p

She is one of the few court appointees in recent years to mix substantial political experience with the law. She was Republican state senior representing a wealthy suburb of Phoenix, majority leader of the senate and was mentioned as a candidate for Arizona governor. In 1972, O'Connor was co-chairman of the Nixon campaign in her state.

O'Connor returned to Arizona, where her parents lived, after graduating third in a Stanford law class that included current Supreme Court Justice William H. Rehnquist. At Stanford, she was good enough to make the law review.

In Phoenix, she joined a general law practice with one other lawyer, Thomas H. Tobin, and left after about a year, Tobin recalls, to have her three children. She returned to law as an assistant attorney general for the state of Arizona in 1965.

As a state senator, she sponsored and supported a wide variety of bills on social issues but followed no consistent ideological line.

She co-sponsored a bill opposed by antiabortionists to establish a state family planning service. But she voted for a bill giving hospitals and doctors the "right to refuse" to perform abortions.

She voted for a resolution urging Congress to stop school busing to achieve racial balance, and for a resolution opposing federal gun controls.

But she favored legislation to provide workers' compensation for migrant farm workers, to encourage bilingual education in the state and to improve conditions for mental patients.

At first, she supported the Equal Rights Amendment. "I remember the day it passed out of Congress," said current Arizona Senate President Leo Corbert. "There were some of us that didn't know what it meant. All of the women, including Sen. O'Connor, said we should pass it before the state of Hawaii did. They wanted to be first.

"But then their ardor sort of cooled."

Corbert says that O'Connor turned her attention to more limited bills designed to equalize conditions for women. She helped push through, for example, a measure allowing women to buy and sell property.

Many Supreme Court critics say the current justices badly need a negotiator in their ranks. As majority leader, Arizona politicians say, O'Connor was good at that. "She was good at identifying what the issue was and articulating it to everyone," Corbert recalled. "She managed bills very sensitively and kept some things from becoming too controversial," said Alice Bendheim, state ACLU chairman.

"She was a very political animal," Bendheim said. "She started out as a moderate Republican and then, after about 1974, moved toward the right."

Women, although still vastly outnumbered by men judges, were represented relatively early at high levels in the Arizona judiciary. The country's first woman state chief justice served in that state in the early 1960s. So O'Connor's election in 1975 to the Superior Court of Maricopa County shocked no one.

Neither did her performance on the bench. Lawyers who practiced before her recalled no decisions departing from precedent. She excluded evidence when necessary, they say, yet dealt sternly with those convicted, particularly those convicted of second offenses.

"She would not bend over backwards to give any breaks to anyone who had previously been given a break," said David Derickson, a Superior Court judge who practiced before O'Connor as a lawyer.

"But she kept a tight rein on everybody. I remember a couple of incidents when I was a defense attorney where I suggested that the prosecutor ought not to be arguing such a badly wrong position. I said I knew the judge could see through the smoke."

O'Connor cut him off, Derickson recalls. "'I appreciate the compliment,' she said. 'But I'll decide what's smoke or what's not.'"

"She was very strict early in her career," said John Foreman, a former public defender and now a private criminal defense lawyer. "There were quite a few young attorneys who got their backsides roasted by her. She does not tolerate nonsense or people who don't know what they're doing."

Lawyers remembered only one occasion when she imposed the death penalty. The defendant had been convicted of a contract murder, said the the defense lawyer, Tom Henze. Following the trial, O'Connor was informed that statements by a key witness that contradicted his trial testimony had been concealed from the defense. She then canceled the verdict and the death sentence and ordered a new trial.

O'Connor initially was appointed to the Court of Appeals to fill an unexpired term. Most of that court's cases involved dry matters like contracts. But she also occasionally dealt with more controversial issues.

In September, 1980, she ruled that making an indigent tenant put up large sums of money in order to sue a landlord unconstitutionally discriminated against poor people.In March, 1980, she ruled that a public college's trustees had violated the law by holding meetings in private.

"She has done a good and competent job," said John P. Frank, a noted constitutional scholar who practices in Arizona and describes himself as a "yellow dog Democrat."

"But you can't draw much social significance from the kind of work that court does. In terms of general social outlook, I'd say she's conservative but not reactionary. I would say she would tend to have views more or less similar to Chief Justice Burger. But she won't be a right-wing ideologue like Rehnquist."

"Some of my more radical friends picture her as very, very conservative," said ACLU Chairman Bendheim. "But if you put her on the spectrum of conservatives, especially in Arizona, I don't think she's that far over to the right. I don't think she would be an activist judge in any direction, for any cause."

The only recent statement of O'Connor's philosophy toward the federal courts came in the William and Mary Law Review this summer. In an article about the relationship between state and federal courts, O'Connor expressed the view that federal judges were exercising more authority than they should in constitutional matters, particularly in civil rights suits.

When a state judge becomes a federal judge, she said, "he or she does not become immediately better equipped intellectually to do the job. . . . If we are serious about strengthening our state courts and improving their capacity to deal with federal constitutional issues . . . it is a step in the right direction to defer to the state courts and give finality to their judgments on federal questions where a full and fair adjudication has been given in the state court."