A gay federal judge in San Francisco presiding over the Proposition 8 trial on same-sex marriage should be evaluated on whether he is impartial and fair and should not be forced to step away from the case because of his sexual orientation.

That’s the assessment of many legal observers as well as supporters and opponents of same-sex marriage.

But while agreeing that Judge Vaughn Walker, 65, shouldn’t remove himself from the case solely on grounds of his sexual orientation, advocates on both sides of the gay marriage issue disagree sharply over whether Walker has shown a bias in favor of the plaintiffs in the case, who seek to overturn Proposition 8.

“Whatever Judge Walker’s sexual orientation is, it’s not a reason to take him off the case,” said American Civil Liberties attorney James Esseks, who works for the ACLU’s LGBT rights project.

“Judge Walker’s sexual orientation … doesn’t make him unable to decide the issues before him impartially,” Esseks said in an ACLU blog. “What does matter is how he conducts himself as a judge, and his ability to put his own views and background aside and focus on the law and the constitution.”

Walker serves as chief judge for the U.S. District Court in Northern California, where two same-sex couples filed a lawsuit last year challenging the constitutionality of the ballot proposition. California voters approved the ballot measure in November 2008, which overturned a decision by the state’s highest court legalizing same-sex marriage.

Lawyers and advocates defending Proposition 8 have accused Vaughn of being biased against the measure during a 12-day trial in January, which recessed before news surfaced in the San Francisco Chronicle that Vaughn is gay.

Although some Proposition 8 backers associated with religious groups called for Walker’s removal from the case because of his sexual orientation, most conservative activists defending the ballot measure have said the judge should instead step down because of the alleged bias he has shown.

“I have no reason to doubt that there are homosexuals who could preside impartially over this case, just as I have no reason to doubt that there are heterosexuals whose bias in favor of, or against, same-sex marriage would unduly skew their handling of the case,” said Ed Whelan, a conservative commentator, in a National Review essay.

But Whelan added, “From the outset, Walker’s entire course of conduct in the anti-Prop 8 case has reflected a manifest design to turn the lawsuit into a high-profile, culture-transforming, history-making Scopes-style show trial of Prop 8’s sponsors.”

Whelan pointed to a U.S. Supreme Court decision to overturn Walker’s initial plans to allow the Prop 8 trial to be broadcast over the Internet. He also noted that an appeals court consisting mostly of Clinton appointees overturned, in part, a procedural decision by Walker to allow the plaintiffs to obtain internal communications, including e-mail, from organizers of the Prop 8 election campaign.

LGBT activists backing the plaintiffs’ case against Prop 8 have disputed allegations that Walker is biased, saying the ballot measure’s defenders are angry at the judge because of his rulings against them on a number of legal issues. Supporters of the plaintiffs, including their attorneys, say Walker’s rulings during the trial were based on legal principals and decisions of past cases, not on bias.

Walker is currently reviewing the evidence presented by a series of witnesses during the trial and is expected to resume the case to hear closing arguments in March.

“Every judge has a sexual orientation,” said American University law professor Nancy Polikoff, in commenting on critics who say Walker should step down from the case because he’s gay.

“If a judge were straight, would a gay plaintiff have a ground to recuse the judge because he was straight? No, that’s ridiculous,” she said. “And the same thing is true with any assertion that being gay makes him unable to hear the case. It’s not evidence of having any kind of prejudice that would stop a judge from being able to decide a case on the law.”

Walker was first nominated for his judicial position by President Ronald Reagan in 1987, but Democrats in Congress initially blocked the nomination on grounds that Walker’s record as a lawyer in private practice showed insensitivity toward civil rights, including gay rights.

President George H.W. Bush renewed Walker’s nomination in 1989, and the Senate later approved it after receiving assurances that he would rule impartially and fairly.

In a Feb. 9 editorial, the San Francisco Chronicle said Walker’s record of more than 20 years on the bench has shown he has fulfilled his promise.

“Walker did not think his private life was relevant to his ability to preside with fairness in the Prop 8 trial,” says the editorial. “There is nothing in his long and laudable career to suggest otherwise.”