Membership in The Federalist Society, a self-described group of conservative and libertarian lawyers interested in "reforming the current legal order," apparently has raised red flags among some groups questioning Supreme Court nominee John Roberts' (search) history with the organization.

Roberts declined to answer questions Monday from reporters asking why his name was listed in the group's 1997-1998 leadership directory. At that time, Roberts was a partner in a private law firm and was named a member of the steering committee in the group's Washington chapter.

When Roberts was first nominated last week by President Bush to replace retiring Supreme Court Justice Sandra Day O'Connor, several press reports listed him as a member of the group. The White House originally corrected reporters, saying Roberts did not recall ever belonging to the group, founded in 1982 and home to such figures as former Supreme Court nominee Robert Bork, former George H.W. Bush adviser C. Boyden Gray, former Oklahoma Sen. Frank Keating and Utah Republican Sen. Orrin Hatch.

After meeting Monday with Sen. Dianne Feinstein, D-Calif., Roberts demurred when posed the question of how he couldn't remember belonging to the group.

After smiling, but offering no reply, Feinstein interjected for him, saying, "I don't think he wants to take any questions."

"No, no, no thanks," Roberts added.

Roberts is spending a fourth day on Capitol Hill Monday meeting with members of the Senate Judiciary Committee. Besides Feinstein, with whom Roberts had a photo opportunity after their meeting, the nominee also met with Sens. Joe Lieberman, D-Conn., John Cornyn, R-Texas, and Sam Brownback, R-Kan.

Feinstein told reporters that she found Roberts to be a very interesting nominee.

"This clearly is, I think, a very unusual person because you do get the direct feeling of humility and modesty. Yet he apparently is very precise in his writing and his ability to put cases together. I don't think there was anybody on the court quite like he will be because my sense is he really grapples with the law rather than any extraneous bias," Feinstein said.

She added that while she did not ask Roberts about his relationship with The Federalist Society, "it's not a dispositive question in my view. It would be interesting to know the answer."

Cornyn said after his meeting with Roberts that he thought forgetting about paying membership dues in an organization is not uncommon.

"It's not like being a member of the Communist party ... The Federalist Society hosts debates from a lot of people with different viewpoints that serves a useful purpose for some lawyers ... I don't think it should be a limiting factor," he said.

While Roberts holds meet-and-greet sessions with members deciding his fate, some Democrats have begun asking for documents Roberts wrote while working for both former Presidents Reagan and Bush.

Roberts worked in the Reagan White House counsel's office from 1982-1986. He also was principal deputy solicitor general, a political appointment in the administration of the first President Bush.

Some documents during his time in the administrations are already available to the public at the presidential libraries of Ronald Reagan, in Simi Valley, Calif., and George H.W. Bush, in College Station, Texas.

Others have yet to be cleared for security and personal privacy by archivists and, under law, by representatives of the former administrations and the current president. Administration officials for the current President Bush have said they don't plan to release that work product, protected by attorney-client privilege.

"Generally, that's not something that the administration or any White House would be inclined to share because it is so sensitive and ... does chill communications between line attorneys and their superiors within the Department of Justice," Attorney General Alberto Gonzales, a former counsel to the president, said on "FOX News Sunday."

"That would be something that we'd have to look at very, very carefully," Gonzales said, adding, "Rather than prejudge the issue, let's wait for the Judiciary Committee to make its requests, and then we can evaluate the requests and hopefully reach an appropriate accommodation."

The Senate Judiciary Committee (search) has yet to ask for such material for its hearings, but some Democrats, including Sen. John Kerry (search) of Massachusetts, have urged the White House to release "in their entirety" any documents written by Roberts. Other Democrats sounded skeptical of administration claims to privacy.

"This is not a game of 'gotcha,'" said Sen. Charles Schumer, D-N.Y., arguing that the document dump would serve the purpose of educating senators about Roberts' judicial philosophy and legal reasoning. "Document requests ... are a means to simply determining Justice Roberts' judicial views."

"It's a total red herring to say, 'Oh, we can't show this,'" Sen. Patrick Leahy (search) of Vermont told a network news show that aired Sunday morning.

Leahy, senior Democrat on the Judiciary Committee, said material written in confidence at the Justice Department by other nominees has been provided in the past — for instance by President Ronald Reagan when he nominated William H. Rehnquist for chief justice.

"And of course there is no lawyer-client privilege," he said. "Those working in the solicitor general's office are not working for the president. They're working for you and me and all the American people."

But Feinstein said "unless it relates to confirming something that becomes a major issue," she didn't think a request for documents from Roberts' time as solicitor general would be very important to Democrats.

Added Lieberman, one of the "Gang of 14" who resolved the last nominee stand-off among Republican and Democratic senators: "I'd hate to see us get into a battle over whether the administration was going to share documents instead of the basic question of is Judge Roberts deserving of confirmation to be a justice of the United States Supreme Court."

Court watchers and party backers disagree about the value of such papers as well as the precedent of turning them over.

Preserving the classified status of the documents is necessary "especially when you're dealing with what essentially are privileged communications, a lawyer's deliberative process when it comes to issues of how [Roberts] dealt with cases," Tammy Bruce told FOX News. "There's a recognition that with Supreme Court justices, you don't ask them how they are going to decide their cases because it is deliberative. It's the same with this as with the paper. Americans will reject it. It will be petty ... the leadership at least realizes it shouldn't go down this road."

However, Democratic strategist Bob Beckel pointed out that the administration is trying to get the Senate to confirm John Bolton, Bush's nominee to the United Nations, while withholding Bolton's work product at the State Department. Bolton's nomination has been held up in the Senate Foreign Relations Committee for months.

"Let me make a point about John Bolton. He still isn't ambassador of the U.N., is he?" Beckel asked.

FOX News' Julie Asher and The Associated Press contributed to this report.