Supreme Court nominee John Roberts (search) earned a "well qualified" rating from the American Bar Association (search) on Wednesday, clearing one hurdle in his path to joining the high court.

The rating by unanimous vote of an ABA committee was disclosed as the Senate Judiciary Committee announced plans for the start of confirmation hearings on Sept. 6. Roberts will face almost an hour of questioning from each of the 18 senators on the committee.

The committee also will hold one hearing that will be closed to the public.

For more than 50 years, the ABA has evaluated the credentials of nominees for the federal bench, though the nation's largest lawyers' group has no official standing in the process. Supreme Court nominees get the most scrutiny.

This is the fourth time the ABA has rated Roberts. He was designated as well qualified in 2001 when he was nominated for the U.S. Court of Appeals for the District of Columbia Circuit. He earned the same rating in 2003 when he was nominated again for the appeals courts and then confirmed. He was rated as qualified as an appeals court nominee in 1992, but the Senate never took up that nomination.

Roberts, 50, would replace retiring Justice Sandra Day O'Connor (search).

A 15-member ABA committee handled the work, including a review of opinions and legal briefs. ABA spokeswoman Nancy Slonim said the vote was unanimous.

The possible ratings are "well qualified," "qualified" and "not qualified."

"Judge Roberts is a mainstream nominee, and extremely well qualified, despite the efforts by some to mischaracterize him," said a Republican supporter on the committee, Sen. John Cornyn of Texas.

The top Democrat on the Senate committee said ABA reviewers were unable to look at all of Roberts' documents from his time as a government lawyer. Roberts worked in the solicitor general's office under the first President Bush and in the White House counsel's office under President Reagan.

"It's regrettable that they were not able to take the time to review the documents that now have been provided to the Senate," said Sen. Patrick Leahy of Vermont. "Nor have they or the Senate yet had access to work papers from Judge Robert's most substantive earlier post, in the solicitor generals office. But we thank them for their work."

In the confirmation hearings, each senator on the committee will get at least 50 minutes to question Roberts and listen to his answers: 30 minutes in a first round and 20 minutes in a second round.

The chairman, Sen. Arlen Specter, R-Pa., and Leahy also wrote committee members that more rounds could be set if necessary.

Roberts will be able to give an opening statement on the first day of the hearings, after the 18 senators give 10-minute opening statements. The questioning is to begin on Sept. 7.

One committee Democrat, Sen. Charles Schumer of New York, said Roberts should explain why he kept hearing a lawsuit against the Bush administration while he was being interviewed for the Supreme Court.

Roberts sat on a three-judge panel that in July refused to block military tribunals for terrorism suspects. Bringing suit was Salim Ahmed Hamdan, a Yemeni who once was Osama bin Laden's driver.

Roberts had begun interviewing with administration officials in April for a possible vacancy on the court, according to his questionnaire submitted to the Senate.

"Judge Roberts should explain as soon as possible why he thought it was appropriate for him to continue hearing this case," Schumer said.

As for the closed hearing, Specter had said earlier that he might keep the public out if confidential information were to be discussed.

Meanwhile, more than 1,700 documents involving Roberts are being kept from the Senate and the public by the National Archives and the Ronald Reagan Presidential Library, officials said Wednesday.

The material is part of nearly 50,000 pages of records related to Roberts' time as associate counsel to Reagan.

The National Archives in Washington and the Reagan Library in Simi Valley, Calif., planned on Thursday to release more than 38,000 documents involving Roberts. They cover subjects such as abortion, school prayer and the war powers of the president.

Those documents were reviewed by the National Archives staff to protect material deemed sensitive for national security, privacy and law enforcement reasons. The agency said 1,708 pages have been withheld under Freedom of Information Act exemptions.

Some 9,864 pages have been released, including 5,000 on Monday.