Updated

John Roberts (search) is coming under scrutiny by both liberal and conservative groups after news got out that he did some pro bono work on behalf of gay-rights activists for a Supreme Court case.

While most lawmakers will be eying writings Roberts did during his tenure as deputy solicitor general under the first President Bush, the Supreme Court nominee worked for a decade at the Washington law firm Hogan & Hartson, where he was a partner making more than $1 million a year.

The case in question was Romer vs. Evans. The Supreme Court in 1996 voted, 6 to 3, to strike down a voter-approved Colorado initiative that would have allowed employers and landlords to exclude gays from jobs and housing.

Roberts' involvement in the case was first reported Wednesday by the Los Angeles Times. The Times reported Friday that the news caught both Roberts supporters and opponents off guard.

Roberts did some pro-bono work on the case on behalf of the plaintiffs, helping their lawyers prepare arguments and participate on mock trials. Roberts did not mention his work on the case in responding to a Senate Judiciary Committee questionnaire that asked for examples of his pro bono work.

Jean Dubofsky, the lead lawyer for the activists challenging the Colorado initiative, told The LA Times that Roberts gave her "absolutely crucial" advice on how to argue the case.

The White House sought to play down Roberts' participation in Romer vs. Evans.

White House spokeswoman Dana Perino told the Times that Roberts spent less than 10 hours on the case, compared with more than 200 hours he spent on two pro bono cases on which he was the lead counsel.

"There is clearly a difference" between his assistance in the Colorado case and his other pro bono work, Perino said, according to the Times.

Another White House spokeswoman Erin Healy told The New York Times that Roberts's involvement was minimal. "As in any other case," Healy said, "it is wrong to equate legal work product with personal opinions."

Roberts didn't disclose the work to Senators considering his nomination and the revelation set off debate about his conservative credentials among groups like Focus on the Family.

During his time as solicitor general for a Republican administration, Roberts handled issues such as abortion, affirmative action, school prayer and capital punishment.

The White House has refused Democrats' request for Roberts' writings on the cases he handled for the government, saying they are protected by attorney-client privilege.

Democrats, including members of the Senate committee that will hold hearings on the nomination beginning Sept. 6, are not so sure. Because Roberts is not speaking publicly ahead of his confirmation hearings, they believe the documents can provide insight into the legal philosophy of the 50-year-old appellate judge and whether his appointment might shift the high court significantly to the right.

"The president cites Judge Roberts' work in this post as one of the reasons he made this nomination, and the committee will want to square these varying accounts to get as close to the truth as we can," said Vermont Sen. Patrick Leahy (search), top Democrat on the Senate Judiciary Committee.

In Rust v. Sullivan, Roberts helped write a brief urging the court to overturn Roe v. Wade, the 1973 Supreme Court decision legalizing abortion. In a second case, Roberts was the lead lawyer in Metro Broadcasting Inc. v. FCC, maintaining the government should not favor minorities in the awarding of broadcast licenses.

The Rust appeal did not involve a challenge to abortion. But Roberts and other lawyers used the case to renew the contention that Roe v. Wade (search) was wrongly decided.

In the affirmative action case, Roberts took the unusual stand of refusing to defend the FCC and its minority preference rules. He wrote that it was "far from clear that the interest in promoting `programming diversity' is sufficiently compelling to justify the use of racial classifications that would otherwise infringe upon equal protection rights."

Abortion rights and affirmative action supporters are wary because Roberts would replace Justice Sandra Day O'Connor (search). She has voted to uphold Roe v. Wade and is the key swing voter on affirmative action issues. O'Connor wrote the dissenting opinion in the Metro Broadcasting case in 1990, when a split court voted 5-4 to uphold the FCC minority preference policies.

Roberts' criticism of racial "quotas" in some documents from his tenure as a White House lawyer during the Reagan administration has alarmed civil rights groups.

Roberts' supporters have cautioned against reading too much into his work in the solicitor general's office. They noted that he was following the lead of his boss, Kenneth Starr (search), who later headed the investigation that led to President Clinton's impeachment.

But in a 1991 resume, Roberts played up his influence. "I had final responsibility for determining whether the United States would seek further review of adverse decisions in some 380 cases," he said.

At least some solicitor general communications have been released to senators in the past, during the failed nomination of Robert Bork (search) by President Reagan. Democrats seized on the extensive paper trail and used it to help scuttle Bork's appointment.

The Associated Press contributed to this report.