WASHINGTON — Moving swiftly to give the U.S. Supreme Court new leadership when it reconvenes next month, President Bush on Monday nominated John G. Roberts to replace the late William Rehnquist as chief justice.
By turning to Roberts, who Bush initially nominated to replace retiring Justice Sandra Day O'Connor, the president may head off a contentious Senate confirmation fight.
Bush said Roberts, a federal appeals judge who once worked as Rehnquist's law clerk, was a known quantity to senators who have spent the past months scrutinizing his legal background and writings.
Nominees to the court must be confirmed by the Senate, and a sitting justice would have been subject to a new confirmation process if one had been picked by the president for the chief's job.
"They know (Roberts') record and his fidelity to the law," Bush said. "I am confident that the Senate can complete hearings and confirm him as chief justice within a month."
The president also indicated he will select someone to fill the associate justice position in "a timely manner." Before Bush selected Roberts the first time, speculation focused on women who might replace O'Connor and on candidates, such as Attorney General Alberto Gonzales of Houston, who would be the court's first Hispanic.
However, since O'Connor has indicated that she will continue to serve until a replacement is confirmed, the White House does not feel immediate pressure to fill the position.
The Senate Judiciary Committee was scheduled to begin hearings on Roberts' original nomination today. Instead they will start on Thursday or later because of Rehnquist's funeral on Wednesday.
Senate Democrats have been relatively restrained in their criticism of Roberts.
But a number of key lawmakers indicated Monday that he will face heightened scrutiny and a different set of questions now that he has been nominated for chief justice.
Allotted the same one vote as the other eight justices in deciding cases, the chief justice is influential in picking which cases will be heard by the court and, when he is in the majority, he selects which justice will write the court's opinion.
Sen. Patrick Leahy, D-Vt., the ranking Democrat on the Judiciary Committee, said Roberts' nomination to be chief justice means "the Senate's advice and consent takes on an added dimension."
Democrats are expected to probe more into the management and leadership skills of the nominee and press harder for the White House to turn over documents relating to Roberts' time as deputy solicitor general under former President George H.W. Bush.
The administration has refused to make public those documents but has released 60,000 papers related to Roberts work in the Justice Department White House Counsel's Office in the Reagan administration.
Those memos, which portray Roberts as an aggressive attorney committed to carrying out the Republican agenda on issues such as affirmative action, voting rights, and abortion, have already prompted liberal groups to oppose his nomination.
Ralph Neas, president of the leading liberal group People for the American Way, said Monday that the nomination of Roberts to be chief justice "raises the stakes for the court and the American people exponentially."
But Sen. John Cornyn, R-Texas, said he failed to understand increased concern about the nominee, since Roberts now would be replacing someone with a similar conservative philosophy and probably would leave the ideological balance on the court unchanged.
O'Connor has been considered a moderate swing vote on the court, and liberals were concerned that Roberts would have shifted the court in more conservative direction.
"Roberts for Rehnquist should be less controversial," said Cornyn, a former judge who sits on the Judiciary Committee.
Like Rehnquist, Roberts is considered a brilliant jurist — he finished first in his law school class at Harvard and Rehnquist was first at Stanford — and he is a congenial, collegial accomplished writer.
Experts said Bush's choice of Roberts was a shrewd one that reduces the president's political headaches as he faces criticism over the administration's response to Hurricane Katrina, sharply rising energy prices, continued bloodshed in Iraq, and declining poll ratings.
Norman Ornstein, a scholar at the American Enterprise Institute, said that Roberts has the temperament to be an effective chief justice, unlike some other rumored candidates such as Justice Antonin Scalia, who is known for his scathing opinions.
"He is not a combative person," Ornstein said of Roberts.
At age 50, Roberts is younger than justices on the Supreme Court, where the average age is 70. But Roberts is extremely familiar with the personalities and dynamics of the high court after arguing 39 cases before it.
In an article in this week's issue of The New Yorker, Supreme Court Justice Anthony Kennedy was quoted as calling Roberts "a marvelous oral advocate. So we feel like we know him in that regard."
Standing by Bush at the White House on Monday, Roberts said he was "honored and humbled" by the nomination.
"I'm very much aware that if I am confirmed, I would succeed a man I deeply respect and admire, a man who has been very kind to me for 25 years," he said of Rehnquist.
Senate Majority Leader Bill Frist, R-Tenn., said he will press for a final confirmation vote by the end of September. The court session opens Oct. 3.
Without a chief, Justice John Paul Stevens, part of the court's liberal wing, would fill in because he has seniority on the court.