A federal appeals court ruled in San Francisco Friday that opponents of California's ban on same-sex marriage, known as Proposition 8, can't obtain internal campaign documents for the voter initiative for use as evidence in a January trial.
A three-judge panel of the 9th U.S. Circuit Court of Appeals said that disclosure of the materials would violate the First Amendment free-speech rights of those who worked on the campaign.
Circuit Judge Raymond Fisher wrote that release of the documents would have a "chilling effect on political association and the formulation of political expression."
The disclosure was sought by two same-sex couples who filed a lawsuit claiming the ban violates their federal constitutional rights.
The lawsuit is due to go to trial before U.S. District Judge Vaughn Walker in San Francisco on Jan. 11.
The three judges on the panel unanimously overturned a pretrial ruling in which Walker said the plaintiffs could seek evidence concerning Proposition 8 supporters' campaign strategy and advertising.
Fisher, writing for the panel, said, "The freedom to associate with others for the common advancement of political beliefs and ideas lies at the heart of the First Amendment."
The ruling was expected because the panel, after hearing arguments on Dec. 1, issued an order on Dec. 3 saying that the Proposition 8 sponsors had made a "strong showing" they were likely to win their First Amendment argument. That order continued a stay on discovery, or collection of evidence, on the internal campaign documents.
Yusef Robb, a spokesman for the same-sex couples' lawyers, said the plaintiffs have plenty of other evidence and said the attorneys don't expect the ruling to delay the trial.
Robb said, "We're ready to proceed on January 11 with an overwhelming case that is based on multitudinous evidence, witness testimony and the U.S. Constitution."
Walker is scheduled to hold a pretrial conference on the case in his San Francisco courtroom on Dec. 16.