Leafing through the papers of the late Supreme Court Justice Thurgood Marshall recently, I came across a striking document that shows how dramatically the justices' vision of their role in society has changed over the past 30 years. It was a letter that Justice William Brennan sent to Chief Justice Warren Burger in the spring of 1971, advising him about how he should write the court's opinion upholding busing at public schools. Brennan's words did not focus on the legal subtleties of the case; rather, he urged the chief justice to think about the "tone" of what he was writing and how people would react to it.

"The matter of approach has assumed major significance in light of signs that opposition to Brown [v. Board of Education] may at long last be crumbling in the South," Brennan argued, pressing Burger to "avoid saying anything that might be seized upon as an excuse to arrest this trend." Brennan went on to refer to a memo from Justice Potter Stewart aimed at holding school boards to Brown's desegregation mandate: "Potter," wrote Brennan, "gets across the message so important to emphasize in this delicate area."

None of the justices I observe on the bench today--neither conservative nor liberal--would think of taking such an approach. None would say the court's opinion should set a "tone" for addressing social problems or would keep an eye on what governors are up to, as Brennan also urged. None would consider it his or her place to do so.

Gone, of course, is the liberal activist court of three decades ago, which took the lead against Southern white resistance to desegregation, kindled the fight for equality among the races and between men and women, and attempted to settle the nation's dilemma over abortion. In its stead, the more restrained and legalistic Rehnquist court approaches the law as a group of professional judges, with the hope of reflecting the norms--not articulating the ideals--of today's society.

Gone is the self-consciously loud voice the court once spoke with, boldly stating its position and calling upon the people and other institutions of government to follow. Today's justices do not engage in eloquent language to provoke political and public support. They are as unwilling to use their opinions to influence the nation's morals and mores as they are unwilling to look for the meaning of the law beyond the words of the Constitution.

Gone, too, is the very notion, notable in the correspondence from the courts of chief justices Earl Warren (1953-69) and even Nixon-appointee Burger (1969-86), that the court should act in concert with the president and Congress, as a bulwark for the poor and disenfranchised. Today, the court's boundaries with the other branches of government are more rigid. The Rehnquist court, known for its narrow interpretation of the Constitution and federal statutes, sees its job as producing legal documents, not issuing calls to action.

The current majority decides only the case before it, focusing on the legal contours of the problem, rather than addressing larger dilemmas or treading where the rest of the nation has not yet gone. In a recent--and somewhat extreme--example, when the court announced it would take up a dispute involving school prayer, it carved away the broader national question about what sort of litany can be used at graduations and other ceremonies, and said it would decide only whether student prayer at football games violated the separation of church and state.

The justices' opinions carefully parse the words of each statute: What precisely did Congress want in a law? Most of the justices are thorough and clear, but spare with the passion and prose that hit home with people. In some of their most important recent opinions, key justices highlighted adherence to constitutional structure and, in Justice Anthony Kennedy's words, "the theory and utility of our federalism." The one agenda associated with the five most conservative Rehnquist justices--an attempt to curb the reach of the federal government and restore authority to the states--is driven by a concern that governmental structures, not individual lives, are out of kilter. While the court's decisions reining in federal authority are controversial, they have only modestly affected Congress's overall statutory power, and it remains to be seen what those decisions' practical consequences will be.

The transformation of the court is a product of its people and of our times. One important factor is Chief Justice William Rehnquist himself. Appointed to the court by President Richard Nixon in 1972 and elevated to chief in 1986, Rehnquist comes from the political right. But he engages in no special pleadings. He doesn't believe it is his place to try to persuade his colleagues to go beyond where they would naturally go.

The chief justice does not have Warren's reputation for persuasion, Brennan's for cajoling nor Burger's for arm twisting. In 1989, he came within a hairbreadth of writing an opinion for the court effectively overturning the landmark abortion-rights decision, Roe v. Wade. But, just days before the opinion was to be issued, Justice Sandra Day O'Connor demurred and stripped Rehnquist of his five-justice majority. O'Connor suffered no wrath from the chief, though; it was Justice Antonin Scalia who attacked her for balking. In a blistering opinion, he said her reasoning could "not be taken seriously." Though not a rousing orator, if there is a justice on the current court who is willing to strike a moral stance and put on a more activist mantle, it is Scalia.

The chief justice also adopts a modest approach to the opinions he writes. When Rehnquist penned a crucial 1995 ruling striking down a federal law forbidding guns near schools and rolling back nearly six decades of expansive interpretation of congressional power, his recitation of constitutional history was dry, even perfunctory. There was barely an acknowledgment of the fact that this was a major departure for the court--and the fulfillment of a quest Rehnquist had declared years before: to win a majority to curb Congress.

For most of the others, across the ideological spectrum, pragmatism reigns. Justice Ruth Bader Ginsburg, who was the first Democratic appointee to the court in 26 years when she was named in 1993, described her approach as "rooted in the place of the judiciary in our democratic society . . . apart from the political fray." A few weeks ago, when Kennedy spoke before a group of high school students, he asked, "Do I make policy? Was I appointed for life to go around answering these great questions and suggesting answers to the Congress? That's not our function. . . . And we also think it's very dangerous for people who are not elected, who have lifetime positions to begin taking public . . . stances on issues that political branches of government must wrestle with." The legislatures are where the action should be, according to this majority.

That was the theme of one of the biggest recent decisions. Two years ago, when the court ruled that there was no constitutional right to physician-assisted suicide, Rehnquist showed great regard for state laws banning assisted suicide and observed that legislatures themselves were beginning to reconsider whether patients near death should be able to seek a doctor's help in ending their lives. The court was not going to interfere with that process and assert its own idea of what was right.

Justice David H. Souter, who is more liberal than the chief, agreed: "The court should . . . stay its hand to allow reasonable legislative consideration." Overall, the justices' rhetoric stood in marked contrast to that used in 1973, when the court took it upon itself to try to settle the abortion debate--an equally controversial issue that was raging in the states.

In the same vein, the current court does not use its opinions to address the welfare of the nation or the disparities in life's circumstances--another contrast to the Warren-era rhetoric. In 1969, when the court struck down state laws setting residency requirements for families on welfare, the majority spoke of the human need for food and shelter: "[W]e do not perceive why a mother who is seeking to make a new life for herself and her children should be regarded as less deserving because she considers, among other factors, the level of a state's public assistance." In comparison, last year, when the court threw out a California law that stopped new residents from getting full welfare benefits until they had lived in the state for a year, the court not only rejected the expansive legal reasoning of the 1969 court, it steered clear of heart-rending rhetoric.

Where the preceding courts were dauntless, today's majority appears apprehensive. In its recent decisions invalidating affirmative action and other race-based policies that cause "reverse discrimination," the majority continually has left the door open to some sort of affirmative action. O'Connor, the voice of the court in this area, seems to fear doing something definite, irreparable: "The unhappy persistence of both the practice and the lingering effects of racial discrimination against minority groups in this country is an unfortunate reality, and government is not disqualified from acting in response to it."

Such tentativeness is part of today's "downsized" court, according to Georgetown University law professor Mark V. Tushnet. He describes the justices as having "chastened aspirations," and argues it is part of a larger change in American government and politics over the last 25 years. "Small-scale programs with modest aims characterize the new constitutional order. . . . [P]overty is to be alleviated by ensuring that the poor obtain education and training to allow them to participate actively in the labor market, rather than by providing generous public assistance programs."

University of Chicago law professor Cass Sunstein writes approvingly of this "minimalist" trend, saying the court should usually decide only one case at a time, rather than trying to resolve larger issues that people are still divided on.

"This court isn't as attuned to the public's reactions," he said recently. "Chief Justice Warren . . . believed that if you're going to take very bold steps, you're under some pressure to make it clear to the public why you're doing that. A court that is more incremental is less concerned about how it explains its rulings to the public."

Sunstein also observes that the Rehnquist court is hardly unique in its approach. "American constitutional law is rooted in the common law, [which] typically proceeds case by case, offering broad rulings only on rare occasions, when the time seems right."

Some of the current justices have remarked that one of the things that makes the job so daunting is that every word they write is dissected and can become part of the controversy of the day. What they'd like to avoid doing is just what Brennan and other justices of his generation strove to do: move the people. Yet, in the end, while the justices can try to cordon themselves off, they never will remove themselves from the center of American life. That is the inevitable consequence not of these particular nine men and women but of what they collectively must do: decide the ultimate law of the land.

Joan Biskupic, who covers the Supreme Court for The Post, is co-author of "Guide to the U.S. Supreme Court" (Congressional Quarterly Inc.).