The U.S. Supreme Court today rejected an Arlington group’s contention that people who sign initiative and referendum petitions enjoy a constitutional guarantee of anonymity.

However, justices concluded, compelling disclosure of the names can be challenged under the First Amendment on a case-by-case basis, leaving the door open for Protect Marriage Washington to continue fighting to keep secret the names of 138,000 people who signed petitions for Referendum 71.

Petition signers wanted to hide their names because of worries of intimidation. But the 9th U.S. Circuit Court of Appeals in San Francisco refused to keep their names secret. The Supreme Court stepped in and temporarily blocked release of the names until the high court could make a decision.

The court now says disclosing names on a petition for a public referendum does not chill the signer’s freedom of speech enough to warrant overturning the state’s disclosure law.

Chief Justice John Roberts, writing the 8-1 judgment for the court, said it is vitally important that states be able to ensure that signatures on referendum petitions are authentic.

“Public disclosure thus helps ensure that the only signatures counted are those that should be, and that the only referenda placed on the ballot are those that garner enough valid signatures,” Roberts said. “Public disclosure also promotes transparency and accountability in the electoral process to an extent other measures cannot.”

But Roberts also said that the court’s opinion deals with whether disclosure of the names on referendum petitions as a whole violates the First Amendment, not solely the Protect Marriage Washington case.

The intimidation that anti-gay rights supporters fear is not present in other referendum issues like tax policy, revenue, budget or other state law issues, Roberts said. “Voters care about such issues, some quite deeply — but there is no reason to assume that any burdens imposed by disclosure of typical referendum petitions would be remotely like the burdens plaintiffs fear in this case,” he said.

But the chief justice added that Protect Marriage Washington could go back to the lower courts and try again on their specific concern in hopes of getting an exemption.

“Upholding the law against a broad based challenge does not foreclose a litigant’s success in a narrower one,” the chief justice said.

The case now goes back to the lower courts for further arguments.

“This is a good day for transparency and accountability in elections — not just in Washington but across our country,” said Rob McKenna, Washington state’s attorney general. “We’re pleased the Supreme Court ruled in favor of disclosure, upholding the public’s right to double-check the work of signature gatherers and government — and giving them the ability to learn which voters are directing the state to hold an election on a new law. Citizen legislating is too important to be conducted in secret.”

Justice Clarence Thomas dissented from the court’s opinion.

“In my view, compelled disclosure of signed referendum and initiative petitions under the Washington Public Records severely burdens those rights and chills citizen participation in the referendum process,” Thomas said. “Given those burdens, I would hold that Washington’s decision to subject all referendum petitions to public disclosure is unconstitutional because they will always be a less restrictive means by which Washington can vindicate its stated interest in preserving the integrity of its referendum process.”

Opponents of the law that expanded the rights of gay couples mounted a petition drive that succeeded in getting a referendum on the “everything-but-marriage” law on last year’s ballot. But voters backed the law by a 53 percent to 46 percent tally that granted registered domestic partners the same legal rights as married couples.

While the campaign was under way, gay rights supporters sought access to the petitions under Washington’s open records law. Protect Marriage Washington, the group that organized opposition to the law, objected, saying its members would be harassed if their names were made public.

The 9th U.S. Circuit Court of Appeals in San Francisco refused to keep the names secret, but the Supreme Court stepped in and blocked release of the names before the vote.

The justices later intervened in another case in which gay rights opponents complained about potential harassment. The court’s conservative majority prevented broadcast of the trial on California’s ban on same-sex marriage.

The case is Doe v. Reed, 09-559. It is posted to the right of this story.