Justice John Paul Stevens is widely regarded as one of the most liberal members of the Supreme Court, and regularly spars with conservative Antonin Scalia.

But when he approached an old acquaintance at the American Bar Association's annual meeting in Chicago last month, he was upbeat about President Bush's selection of another cerebral conservative, John G. Roberts Jr., for the court.

"Isn't it great news?" Stevens, 85, said, according to the acquaintance, who asked not to be named because it was a private conversation.

Roberts was still a nominee for associate justice at the time, but Stevens's attitude toward him illustrates an advantage he would bring to the role of chief justice -- a role he is all but certain to play after his four days of hearings before the Senate Judiciary Committee last week.

Roberts is a former law clerk and close friend of the man he would replace, the late Chief Justice William H. Rehnquist, and he is a veteran of 39 oral arguments before the court. That makes him a known quantity to all eight justices, a person they understand to be familiar with the personal relationships and bureaucratic rhythms that have grown up over the past 11 years of unchanging membership at the court.

"I have watched Judge Roberts since he has been an advocate before our court," Justice Sandra Day O'Connor said in July, when Roberts was originally slated to replace her when she retired. "And I and my colleagues have been enormously impressed with his scholarship and his skills."

Roberts will need all of those skills, once the Senate completes work on his nomination this month, as he tries to fashion majorities -- and to guide a comfortable-in-its-ways group of jurists through a transitional period.

At 50, Roberts would be considerably younger than the colleagues he leads (Clarence Thomas, 57, is the only current justice younger than 65). He has already heard suggestions from members of the Judiciary Committee for such innovations as television cameras at oral arguments, and has floated his own notions that the court might be able to increase its caseload while publishing fewer dissenting and concurring opinions.

Equally important, Roberts must represent the federal judiciary in its relations with Congress, which have been difficult in recent years.

Lawmakers from both parties have expressed frustration on subjects ranging from the court's striking down of popular statutes to the judiciary's alleged failure to enforce rules of conduct among its own members. Those tensions have resulted in a number of GOP proposals in Congress to limit the courts' jurisdiction over such issues as same-sex marriage and the Pledge of Allegiance.

Armed with little more than the persuasive authority of his office, Roberts would have to defend judicial independence, without alienating the lawmakers who supply the $6 billion annual budget that fuels the federal court system and its 30,000 employees.

"Chief Justice Rehnquist realized a chief justice's political capital does not go very far, and you can use it up pretty quickly," said Russell Wheeler, a guest scholar in the governance studies program at the Brookings Institution.

At last week's hearings, Roberts promised continuity with Rehnquist's crisp management of the court's internal deliberations, known as the conference.

He noted that, under Chief Justice Harlan Fiske Stone in the 1940s, the meetings were "disasters," because Stone would "critique" each justice's views in turn, so that "the conferences went on for days and everyone ended up hating each other." The clear implication was that he would follow Rehnquist's custom: Each justice speaks once before any other any justice may speak for a second time.

He pledged to adhere to Rehnquist's policy of distributing opinion-writing chores equally among the justices, which also helped reduce friction among them.

"I don't think using opinion-writing assignments as a way to try to promote a particular view or agenda is a good idea," he said.

But Roberts suggested that the court needs fewer dissenting and concurring opinions. Some concurrences are no more than a few paragraphs by a justice explaining why he or she had joined the majority opinion.

O'Connor, in particular, was known for appending concurring opinions when she was in the majority in 5 to 4 cases, thus narrowing the legal precedent set by the case.

Roberts leaned toward those who believe that the extra writings create confusion. "As a lower court judge, I appreciate clear guidance from the Supreme Court," he said.

He also suggested that the court could increase its caseload, which has shrunk from about 150 cases per term when Roberts was a law clerk in 1980-1981, to about 75 in a typical term now.

In part that is because Congress gave the court more freedom to refuse certain kinds of cases, but it also reflects the Rehnquist Court's reluctance to hear some cases until they have "percolated" through several lower appeals courts.

"I think there's room for additional cases on the docket," Roberts said.

The other function Roberts would have to perform is that of titular head of the federal judiciary. The courts' relations with Congress have eroded in recent years as judges have accused Congress of ignoring their need for a substantial pay increase and of failing to consult the judiciary before enacting tough new sentencing laws.

For their part, members of Congress from across the political spectrum have complained that the courts, led by the Supreme Court, have been slighting -- or even ignoring -- their views and the views of their constituents.

"I'm old, and in all the years I have been around I don't think I've seen it as strained as it is now," O'Connor told a meeting of West Coast federal judges in July.

At the hearings, Roberts absorbed a lecture from Sen. Arlen Specter (R-Pa.), the committee chairman, about a 1997 Supreme Court decision that struck down a religious-freedom law on the grounds that Congress could not subject states to civil lawsuits for discrimination unless the court found that such a remedy was "congruent and proportional" to the alleged constitutional violation.

The court "plucked" that standard "right out of thin air," Specter said. In other cases, the justices, he said, were guilty of "denigrating" Congress's reasoning.

Such complaints about the court's states' rights decisions from moderates and liberals have been common. Conservatives have denounced decisions such as the court's repeated overturning, on free-speech grounds, of federal laws regulating child pornography on the Internet. The right has also denounced the courts' failure to intervene to keep Terri Schiavo's feeding tube connected, as well as lower court decisions ruling the phrase "under God" in the Pledge of Allegiance unconstitutional.

Though the Supreme Court struck down only 128 federal laws during its first 200 years, it struck down 24 between 1995 and 2000.

As chief justice, Roberts would be counted on by his colleagues on the bench to fend off Congress's attacks, rhetorical and legislative.

Roberts would come to that role with an interesting history. As a young aide in the Reagan administration, he defended the right of Congress and others to criticize the courts, and wrote memos saying the Constitution permitted numerous proposals by congressional conservatives of that era to strip the courts of jurisdiction over school desegregation, abortion and school prayer.

But at his hearings, he said, "I'm not sure" if that view is still right, and said he had come to regard such legislation as "bad policy."

"He can do what Rehnquist did fairly well, asserting the important . . . historical value of judicial independence, and reaching out to legislators on an individual basis," Wheeler said.

On a particular conservative sore point -- the Supreme Court's occasional invocation of foreign court rulings to support its interpretation of the U.S. Constitution -- Roberts sided with the right, saying, "I don't think it's a good approach."

But he declined an invitation by Sen. Tom Coburn (R-Okla.) to declare that judges who cite foreign precedent may be guilty of an impeachable offense, as a Republican House bill proposes.