Lawyers for Gov. Jerry Brown are accusing the backers of the state's same-sex marriage ban of engaging in a thinly veiled "witch hunt" against the gay federal judge who struck down Proposition 8 as unconstitutional.

The charge came in legal papers state lawyers filed Thursday in U.S. District Court in San Francisco arguing that the voter-approved ban's sponsors have no basis for trying to get former Chief Judge Vaughn Walker's ruling overturned.

The group that qualified Proposition 8 for the ballot has asked Walker's successor to vacate the judge's decision because Walker revealed after he retired this year that he is in a long-term relationship with another man.

The governor's lawyers say that even though Walker's ruling would enable he and his partner to marry, that would be insufficient evidence of bias to justify throwing out his ruling.