If confirmed by the Senate, the 50-year-old Roberts would succeed retiring Justice Sandra Day O'Connor, long a swing vote on a divided court on abortion, affirmative action, states' rights and other volatile issues.
In 2003, when John G. Roberts was nominated as a federal appeals court judge, three Senate Judiciary Committee Democrats voted against him: Dick Durbin, Edward Kennedy and Chuck Schumer.
Senator Arlen Specter, the Republican who chairs the Senate Judiciary Committee, says he's met Roberts five or six times and the judge has "very fine qualifications." Specter adds that the committee will be reviewing the several dozen court opinions Roberts has written.
"At the minimum people ought to let him be heard and review his record," said Specter, reacting to an abortion rights group that opposed the nomination even before it was announced.
"The president has chosen someone with suitable legal credentials, but that is not the end of our inquiry," said Harry Reid of Nevada, Senate Democratic Whip. "I will not prejudge this nomination. I look forward to learning more about Judge Roberts."
Roberts, a Harvard Law School grad who clerked for Supreme Court Justice William Rehnquist, held several key positions in the Reagan administration. He stayed on through the Bush presidency as the government's second highest lawyer, worked for Kenneth Starr, and had a lucrative private practice before being sworn in by Rehnquist a federal judge.
Roberts' path to the bench was a bit rocky. He was nominated for the court in 1992 by the first President Bush and again by the president in 2001. Those nominations died in the Senate, which signed off on his third nomination, in 2003.
Four years ago, Roberts enjoyed some bipartisan support when 126 members of the District of Columbia Bar, including officials of the Clinton administration, signed a letter urging his confirmation as a federal judge. The letter called Roberts one of the "very best and most highly respected appellate lawyers in the nation" and said his reputation as a "brilliant writer and oral advocate" was well deserved.
A senior administration official told CBS News that Mr. Bush interviewed five candidates and consulted with over 70 senators before making his decision.
Announcing his choice Tuesday night, Mr. Bush said Roberts will "strictly apply the Constitution in laws, not legislate from the bench."
Roberts says he is honored and humbled by the nomination.
"I always got a lump in my throat whenever I walked up those marble steps to argue a case before the court, and I don't think it was just from the nerves," said Roberts of the 39 times he argued cases before the Supreme Court. "I look forward to the next step in the process before the United States Senate."
Senate confirmation hearings are expected in late August or early September.