SAN FRANCISCO >> The sponsors of California’s same-sex marriage ban said Monday that the recent disclosure by the federal judge who struck down Proposition 8 that he is in a long-term relationship with another man has given them new grounds to have his historic ruling overturned.  

Lawyers for the ban’s backers filed a motion in San Francisco’s U.S. District Court, arguing that Chief U.S. District Judge Vaughn Walker should have removed himself from the case or at least disclosed his relationship status because his “impartiality might reasonably be questioned.”

“Only if Chief Judge Walker had unequivocally disavowed any interest in marrying his partner could the parties and the public be confident that he did not have a direct personal interest in the outcome of the case,” attorneys for the coalition of religious and conservative groups that put Proposition 8 on the November 2008 ballot wrote.

They are now asking the judge who inherited the case when Walker retired at the end of February to vacate Walker’s August 2010 decision. The 9th U.S. Circuit Court of Appeals already is reviewing the legal merits of Walker’s ruling at the request of Proposition 8’s proponents.

Lawyers for the two same-sex couples who successfully sued for the right to marry in Walker’s court were reviewing the motion and did not have immediate comment.

Walker, a 67-year-old Republican appointee, declared Proposition 8 to be an unconstitutional violation of gay Californian’s civil rights last summer. He retired from the bench at the end of February. 

Rumors that the judge was gay circulated during the 13-day trial that preceded his decision and after he handed down his ruling. 

Lawyers for Protect Marriage, the coalition of religious and conservative groups that sponsored Proposition 8, however, have not previously raised his sexual orientation as a legal issue.  

Protect Marriage general counsel Andy Pugno said that changed when the judge this month told a group of courthouse reporters about his 10-year relationship. The issue is not that Walker is gay, but that his relationship status made him too similar to the same-sex couples who sued for the right to marry, Pugno said.

“We deeply regret the necessity of this motion.  But if the courts are to require others to follow the law, the courts themselves must do so as well,” Pugno added.

Walker said at the time that he did not consider his sexual orientation to be any more a reason for recusal than another judge’s race or gender normally would be.