The U.S. Supreme Court on Tuesday barred the state from giving out the names of those who signed petitions for Referendum 71, a move that could keep identities of thousands of people secret for months as a heated legal fight runs its course.

On an 8-1 vote, the court backed Justice Anthony Kennedy’s decision on Monday to stay a lower court order that allowed the secretary of state to disclose the names of the 138,000 petition signers. Justice John Paul Stevens indicated he would have turned down the stay request.

The high court said its order will remain in effect until the justices decide whether to involve themselves in this case.

“I think it’s a big win. The names and addresses and other personal information certainly won’t be getting out before Election Day,” said Larry Stickney of Arlington, a leader of Protect Marriage Washington, which qualified the measure for the ballot.

Referendum 71 asks voters to approve or reject the so-called “everything but marriage” law signed by Gov. Chris Gregoire earlier this year. It would give registered domestic partners the same rights, benefits and responsibilities under state law as married couples.

While most domestic partners are gay and lesbian couples, under state law, opposite-gender seniors also can register as domestic partners.

Protect Marriage Washington has been fighting the state to keep the names private. Its lawyers contend signers have a constitutional right to participate in politics in secret if they face a threat of harassment from political opponents.

State attorneys contend the petitions are public records. They say signing a petition for a referendum or initiative that qualifies for a ballot is a legislative act and voters are entitled to know who is behind such measures.

When the 9th Circuit Court of Appeals sided with the state last week, the group’s lawyers rushed to Kennedy with a request for him to keep the ruling from taking effect.

Protect Marriage Washington wanted time to petition the Supreme Court to hear the case. Its lawyers also pointed out they cannot prepare such a petition until the court of appeals issues its written opinion, which it had not done as of Tuesday.

The Supreme Court action didn’t surprise state lawyers, though they had hoped the majority of justices would not back Kennedy.

“Our attorneys were disappointed,” said Janelle Guthrie, spokeswoman for Attorney General Rob McKenna.

Secretary of State Sam Reed said Tuesday he agrees with the reasoning of the 9th Circuit and wants to see the issue clarified as to what his office can and cannot release.

“The Supreme Court is simply preserving the status quo while opponents of disclosure get their full day in court, and we respect that,” Reed said in a statement.

“We continue to support the view of the 9th Circuit and will do our very best to uphold the voters’ desire for transparent and accountable government,” he said.

Meanwhile Tuesday, in a separate but related case, Thurston County Superior Court Judge Richard Hicks maintained a temporary restraining order he issued last week barring the state from handing out names of people who signed petitions for the referendum and several initiatives sponsored by Tim Eyman of Mukilteo.

Hicks said the competing principles of privacy and open government will “have to be reconciled not by a trial court judge in Thurston County, but by a higher court.

“I think it’s a very important issue and I’m glad it’s drawn the attention that it has,” he said.

The Associated Press contributed to this story.