The Waves Minority Judges Always Make

Justice Thurgood Marshall, the first black member of the Supreme Court, ended his 24 years there bitter and frustrated. He had been unable, he said, to persuade his colleagues in many cases concerning racial equality, the cause to which he had devoted his life.

"What do they know about Negroes?" Justice Marshall asked an interviewer. "You can't name one member of this court who knows anything about Negroes before he came to this court."

But the other justices did get to know Justice Marshall, and even the more conservative ones acknowledged that his very presence exerted a gravitational pull more powerful than his single vote.

"Marshall could be a persuasive force just by sitting there," Justice Antonin Scalia told Juan Williams in an interview for a biography of Justice Marshall, recalling the justices' private conferences about cases. "He wouldn't have to open his mouth to affect the nature of the conference and how seriously the conference would take matters of race."

President Obama's nomination of Judge Sonia Sotomayor to serve on the Supreme Court, where she would be the first Hispanic and the third woman, has raised questions about how her background would affect her decision-making. But there is another question, too: How would she alter the larger dynamic among the justices?

The first woman on the court, Justice Sandra Day O'Connor, often says that wise old women and wise old men reach the same conclusions. But empirical research on federal appeals courts tugs in another direction.

In sex discrimination and sexual harassment cases, according a 2005 study by Jennifer L. Peresie in The Yale Law Journal, "female judges were significantly more likely than male judges to find for plaintiffs."

Perhaps more surprisingly, the study found, "the presence of a female judge significantly increased the probability that a male" on a three-judge panel "supported the plaintiff in the cases." Indeed, "panels with at least one female judge decided cases for the plaintiff more than twice as often as did all-male panels."

A study in The Columbia Law Review last year found a similar effect in voting rights cases. "When a white judge sits on a panel with at least one African-American judge," the study, conducted by Adam B. Cox and Thomas J. Miles, concluded, "she becomes roughly 20 percentage points more likely to find" a voting rights violation.

In an interview, Ms. Peresie, a Washington lawyer, cautioned against extrapolating to the Supreme Court from studies of appeals courts. "Maybe one out of nine is different from one out of three," Ms. Peresie said.

Justice Ruth Bader Ginsburg, the second woman to serve on the Supreme Court and currently the only female justice, said that she and Justice O'Connor, who preceded her, brought a distinct perspective to the court.

"As often as Justice O'Connor and I have disagreed, because she is truly a Republican from Arizona, we were together in all the gender discrimination cases," Justice Ginsburg recently told Joan Biskupic of USA Today.

But Justice Ginsburg said her own influence in all sorts of cases at the justices' conferences was uncertain. "I will say something -- and I don't think I'm a confused speaker -- and it isn't until somebody else says it that everyone will focus on the point," Justice Ginsburg said.

Mark Tushnet, a law professor at Harvard and an authority on the Supreme Court, said Justice O'Connor's arrival at the court "did affect the way other justices responded."

"These are older guys," Mr. Tushnet said. "They haven't dealt with women on a professional basis on the whole." Similarly, he said, "very few of the present justices have interacted as equals with Hispanic professionals." All justices bring their life experiences to the bench in some sense, of course, and Justices Marshall, O'Connor and Ginsburg seemed to devote special attention to cases involving the groups they belonged to.

In a 1992 reminiscence, Justice O'Connor wrote that Justice Marshall was "constantly pushing and prodding us to respond not only to the persuasiveness of legal argument but also to the power of moral truth." She recalled the moving stories Justice Marshall would tell to support his view that racism played a pernicious role in the administration of capital punishment.

It is not clear, though, that any of those stories caused Justice O'Connor to change her vote. "Justice O'Connor was not nearly as sympathetic to racial civil rights claims as she was to gender claims," said Lawrence Baum, a political science professor at Ohio State.

Justice Clarence Thomas, the second African-American justice, is by some measures the most conservative justice since 1937, while Justice Marshall was the most liberal. "Thomas is living proof and a daily reminder that not everyone from a particular background has a particular point of view," said David J. Garrow, a historian at Cambridge University, in England.

Judge Sotomayor has attracted attention for her musings in a 2001 speech about the impact her background might have on her decision-making, remarks a White House spokesman on Friday said reflected a poor choice of words.

"I would hope," she said, "that a wise Latina woman with the richness of her experience would more often than not reach a better conclusion than a white male who hasn't lived that life."

She added, in a less noted passage, that giants on the court, including Justice Benjamin Cardozo, the second Jewish justice, had on occasion stumbled. "Let us not forget that wise men like Oliver Wendell Holmes and Justice Cardozo voted on cases which upheld both sex and race discrimination in our society," Judge Sotomayor said.

Still, many judges say that the law is a set of neutral principles that can be applied mechanically and ought not to vary depending on the judge applying them.

Justice Felix Frankfurter, dissenting in a 1943 decision that struck down a law requiring students to salute the flag, reminded his colleagues that he was, as a Jew, a member of "the most vilified and persecuted minority in history" and thus likely to be sympathetic to a broad interpretation of freedoms guaranteed by the Constitution. "But as judges," he went on, "we are neither Jew nor Gentile, neither Catholic nor agnostic."

Cases with special resonance for Hispanics may not have quite the same profile as cases concerning religion, race and gender, but the Supreme Court will nonetheless face several of them in the years to come, particularly in the areas of immigration, election law and language education in the public schools.

The presence of a Hispanic justice, Professor Tushnet said, will have the usual effect. "Every time there's a new justice," he said, "everybody has to say, 'How will he or she react if I say this?' " That is not only an outsider's view. Justice David H. Souter, the justice whom Judge Sotomayor hopes to replace, has written that the addition of a new judicial perspective necessarily unsettles the existing ones on a court.

"Anyone who has ever sat on a bench with other judges knows that judges are supposed to influence each other, and they do," Justice Souter wrote in a 1998 dissent in a death penalty case. "One may see something the others did not see, and then they all take another look."