The move, two days after the death of Chief Justice William H. Rehnquist, opened a new chapter in Bush's drive to reshape the judiciary with conservatives whose decisions could have sweeping consequences on such issues as abortion rights and the limits of government power.
In an Oval Office announcement, with Roberts at his side, Bush said he wanted the Senate to confirm the 50-year-old U.S. appeals court judge in time for him to lead the Supreme Court when its new term begins next month.
The decision meant that Bush had, in effect, promoted Roberts to the most important seat on the bench barely 24 hours before the Senate Judiciary Committee was to begin hearings on his nomination to replace retiring Justice Sandra Day O'Connor.
The hearings have been delayed until at least Thursday.
Roberts would now replace Rehnquist, who died Saturday of thyroid cancer and will lie in repose at the court today and tomorrow. Bush must name another replacement for O'Connor, who reaffirmed in a conversation with the president yesterday that she would remain on the court until her successor's confirmation, the White House said.
The Senate postponed Roberts' hearings to "give time for appropriate respect after the death of the chief justice," said Senate Majority Leader Bill Frist of Tennessee.
Relatively safe selection
The selection of Roberts to succeed Rehnquist, who was credited with steering a distinctly conservative course on the court, was a relatively safe one for Bush as he struggles to recover from the political fallout of the government's response to Hurricane Katrina.
Roberts is widely respected for his legal mind and well-liked for his low-key, personable manner. Democrats and liberal groups bracing for an intense battle with Bush over the future of the court have been hard-pressed to portray Roberts as a reactionary who poses a threat to important constitutional protections.
Roberts "has earned the nation's confidence," Bush said in nationally televised remarks, less than an hour after formally offering Roberts the position in a White House meeting.
Rehnquist's death "leaves the center chair empty [with] just four weeks left before the Supreme Court reconvenes," Bush said. "It is in the interest of the court and the country to have a chief justice on the bench on the first full day of the fall term."
Bush's decision launched a new round of speculation over whom he would pick to replace O'Connor, the court's first female justice and an important swing vote on decisions involving key constitutional questions about abortion and civil rights, among others.
'In a timely manner'Bush said during his morning remarks that he would name someone to follow O'Connor "in a timely manner." Later, he called O'Connor from Air Force One, en route to his second tour of Gulf Coast areas ravaged by Katrina, to inform her of his decision.
Democrats and liberal activists who oppose Roberts said Bush's choice had raised the stakes in the confirmation process, and some demanded the release of more documents from Roberts' past in order to further scrutinize his record.
Sen. Patrick J. Leahy of Vermont, the ranking Democrat on the Judiciary Committee, said "the Senate's advice and consent responsibility takes on an added dimension."
Roberts' nomination - and Bush's eventual choice to succeed O'Connor - "are lifetime appointments that we can expect to extend into the lives of our grandchildren and great-grandchildren," Leahy said in a statement. "The Supreme Court belongs to every American, and these decisions will affect all of us, and the generations who follow us."
Bush sought to paint Roberts as a familiar figure who should have an easy time winning Senate confirmation because senators have already spent weeks studying his writings and opinions.
Senators "like what they see," Bush said. "He's a gentleman. He's a man of integrity and fairness. And throughout his life, he has inspired the respect and loyalty of others."
Roberts, who worked as a clerk for Rehnquist as a young law school graduate, thanked Bush for the "special opportunity" to lead the court.
'Honored and humbled'
"I am honored and humbled by the confidence that the president has shown in me," Roberts said. "And 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."
Bush had been considering choosing Roberts for chief justice even before Rehnquist's death, White House press secretary Scott McClellan said.
The idea "had been something in the back of the president's mind in case" Rehnquist retired, McClellan told reporters.
Bush "knew [Roberts] was a natural-born leader" after interviewing him as a prospective candidate to replace O'Connor, McClellan said. The president "viewed him as someone who had the leadership qualities needed to be able to lead the court."
Bush met with Roberts for the better part of an hour late Sunday afternoon to discuss his elevation to the court's top post.
Administration allies cheered the choice, praising Roberts' undergraduate and law degrees from Harvard and stints as a government and private-sector lawyer. They noted his reputation - gained during an extraordinary 39 oral arguments - as a gifted advocate before the Supreme Court.
Still, some conservative analysts and veterans of the confirmation process criticized Bush for choosing Roberts, saying the choice would ultimately hinder the president's ability to shift the court more strongly to the right.
Bush was "ill-advised" to choose Roberts for chief, said Bruce Fein, a Justice Department official during the Reagan administration. By doing so, Bush may have missed the chance to replace the moderate O'Connor with a solid conservative.
'Squandered advantage'"Now he's got a more difficult time finding someone who can fill O'Connor's seat because the pressure will be to nominate some who's not in the conservative base," Fein said. Bush "squandered the advantage he had with Roberts."
Bush might now be more likely to name a woman or minority as O'Connor's successor. Among the potential choices are Attorney General Alberto R. Gonzales, a close associate whom some conservatives strongly oppose; Samuel A. Alito Jr., a strictly conservative judge on the Philadelphia-based 3rd U.S. Circuit Court of Appeals; and Edith Hollan Jones, a judge on the New Orleans-based 5th Circuit.
Roberts "lacks that enormous stature and long experience on the bench to be able to push and persuade others on the court, especially some of the middle-roaders, and to shape the tone and future of the court," Fein said.
Roberts, nominated by Bush for his current appellate court position, has been a judge for two years.
Following patternIn choosing him for chief justice, Bush followed the pattern of most presidents, who usually turn to jurists from outside the Supreme Court for the job. Rehnquist, who served 14 years as an associate justice before President Ronald Reagan named him chief justice, was one of only five chiefs - out of 16 - who moved up from within.
The chief justice has a largely administrative role on the court but can play a significant part in shaping the slant and tone of consequential decisions. He decides which justice is to write the majority and minority opinions, which explain the court's thinking - and, depending on whether they are written narrowly or broadly, affect how lower courts and states interpret the decision.
The chief justice also plays an important symbolic role, said Carl W. Tobias, a law professor at the University of Richmond.
"It's not chief justice of the Supreme Court, it's chief justice of the United States, and that person turns out to be the face of the federal judiciary," Tobias said.
The most important of the chief justice's responsibilities at the moment, Tobias said, is "being a staunch defender of independence of the federal judiciary."
Rehnquist was known for his passionate defense of the judicial branch, occasionally scolding Congress when he believed it was treading on the judges' turf.
Sun staff writer Gwyneth K. Shaw contributed to this article.