The Senate is expected to begin his confirmation hearings as chief justice either Thursday or next Monday. The opening of Roberts' previously scheduled confirmation hearings, for the position of associate justice, initially was to be Tuesday, but that was canceled until after Rehnquist's funeral on Wednesday.
CBS News' Gloria Borger said the move could solve two problems for the president. If confirmed, Roberts would give the court a new chief justice when it starts its next term. Also, the court would have a full slate of justices to hear cases. That's because retiring justice Sandra Day O'Connor has agreed to stay on until her replacement is found.
"I am honored and humbled by the confidence the president has shown in me," Roberts said, standing alongside Bush in the Oval Office. "I am 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's a man of integrity and fairness and throughout his life he's inspired the respect and loyalty of others," Bush said. "John Roberts built a record of excellence and achievement and reputation for goodwill and decency toward others in his extraordinary career."
The selection of Roberts helps Bush avoid new political problems when he already is under fire for the government's sluggish response to Hurricane Katrina and his approval ratings in the polls are at the lowest point of his presidency.
CBSNews.com Legal Analyst Andrew Cohen said Bush's move would help the president on three fronts.
"It's a decision by the White House that makes sense practically, politically, and legally — a rare trifecta these days. With one deft change of direction, the president all but ensured we will have a new chief justice in place four weeks from now, when the new court term begins," Cohen said.
"At the same time, he placed Senate Democrats in a box from which they are unlikely to be able to escape. And, finally, he gave himself some room to nominate a successor to Justice O'Connor who is perhaps even more conservative than is Roberts," he added.
Despite the brief delay in beginning hearings, Senate Majority Leader Bill Frist, R-Tenn., said he still expects Roberts to be confirmed before the new court session begins on October 3.
"The president has made an excellent choice," Frist said. "Mr. Roberts is one of the most well qualified candidates to come before the Senate. He will be an excellent chief."
Democrats said Roberts will now be held to a higher standard, although they had found little in his record to suggest they would thwart his nomination as associate justice.
"Now that the president has said he will nominate Judge Roberts as chief justice, the stakes are higher and the Senate's advice and consent responsibility is even more important," Democratic leader Harry Reid said Monday in a statement. "The Senate must be vigilant."
Ralph Neas, president of the liberal advocacy group People for the American Way, a major lobbying force in the judicial-selection process, said his group opposes Bush's decision to nominate Roberts for chief justice.
"The death of chief justice Rehnquist and the president's nomination of John Roberts raises the stakes for the court and the American people exponentially," he said.
The president met with Roberts in the private residence of the White House for about 35 to 40 minutes on Sunday evening, then officially offered him the job at 7:15 a.m. Monday when Roberts arrived at the Oval Office.
"This had been something that had been in the president's thinking for some time — in case the chief justice retired or that there otherwise was a vacancy," White House press secretary Scott McClellan said. "The president when he met with him, knew he was a natural born leader. The president knew Judge Roberts had the qualities to lead the court."
McClellan said the White House is confident that Roberts can be confirmed by the Senate by Oct. 3. Bush still has to pick a successor for Associate Justice Sandra Day O'Connor, although she said at the time of her retirement announcement that she would remain until a replacement were seated.
McClellan said Bush called O'Connor from Air Force One en route to Louisiana Monday to talk with her about his decision and told her he would move quickly to find her replacement as well. Talking to reporters, spokeswoman Dana Perino was unable to say whether O'Connor reiterated her earlier promise, however.
Getting a new chief justice of Bush's choosing in place quickly also avoids the scenario of having liberal Justice John Paul Stevens making the decisions about whom to assign cases to and making other decisions that could influence court deliberations. As the court's senior justice, Stevens would take over Rehnquist's administrative duties until a new chief is confirmed.
"The passing of Chief Justice William Rehnquist leaves the center chair empty, just four weeks left before the Supreme Court reconvenes," Bush said. "It's 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 said Roberts has been closely scrutinized since he was nominated as an associate justice and that Americans "like what they see. He is a gentleman. He is a man of integrity and fairness." He said Roberts has unusual experience, having argued 39 cases as a lawyer before the Supreme Court. Bush also said Roberts was a natural leader.
The move was engineered to have all nine seats on the high court filled when the court opens its fall term.
The White House is not opposed to a delay in Roberts' confirmation hearings as long as senators vote on the confirmation before the court session begins on the first Monday of October. Bush already had nominated Roberts to take O'Connor's place. It requires just a little paper shuffling to change the nomination for Rehnquist's seat.
White House chief of staff Andy Card informed members of Congress, calling Frist and Reid. He also called Sen. Arlen Specter, R-Pa., who is the chairman of the Senate Judiciary Committee; Sen. Patrick Leahy, D-Vt., the ranking Democrat on the committee; and House Majority Leader Dennis Hastert, R-Ill.
The White House counsel's office notified the Supreme Court through Justice John Paul Stevens, the senior-most member of the court.
Sen. Charles Schumer, D-N.Y., a member of the judiciary panel, said the nomination "raises the stakes" in making sure that the American people and the Senate knows Roberts' views.
"Judge Roberts has a clear obligation to make his views known fully and completely at the hearings and we look forward to them," Schumer said.
Liberal groups have expressed opposition to Roberts because of his conservative writings as an attorney for the Reagan administration and his rulings as an appeals court judge. However, it does not appear that his opponents have enough votes to block Roberts' confirmation.
That alone might have been impetus for Bush to rename Roberts for chief justice. Bush, with low standing in the polls, might not have the political capital he would need to win a Senate battle over a conservative ideologue who would draw intense opposition.
Rehnquist, 80 at his death, served on the Supreme Court for 33 years and was its leader for 19 years.
Rehnquist, a World War II Army Air Corps veteran, will be buried in a private ceremony at Arlington National Cemetery alongside his wife, who died in 1991, following a funeral that morning at St. Matthew's Cathedral in Washington. He died Saturday at his home.
His body will lie in repose in the marble Great Hall of the Supreme Court building on Tuesday and on Wednesday morning with the public invited to pay its respects.
Five members of the court have lain in repose there: Chief Justices Earl Warren and Warren Burger, and Justices Thurgood Marshall, William Brennan and Harry Blackmun.