Gay marriage proponents in the Pacific Northwest cheered a U.S. court ruling on Tuesday that overturned a California ban on same-sex nuptials, in what they saw as boost to their cause a day before a key vote to legalize such unions in Washington state.

The 9th U.S. Circuit Court of Appeals found California voters in 2008 had unfairly relegated gay and lesbian couples to a lower status than heterosexual couples when the ban was passed.

That ruling came a day before Washington's state House of Representatives was widely expected to vote to legalize gay marriage, even as opponents vowed to place a proposed repeal of the law or an outright gay marriage ban before voters in November.

I'm sure those who are actively campaigning for same-sex marriage legislation in Washington are very happy to have this decision in their back pocket, said Peter Nicolas, a law professor at the University of Washington.

The narrowly tailored appeals court decision was specific to California's experience with gay marriage and did not address whether such unions are a fundamental right for same-sex couples, potentially limiting its application beyond that state.

Some observers say the case will ultimately be decided by the U.S. Supreme Court.

But in the meantime, legal experts said the appeals court ruling could still set the stage for a successful court challenge in Washington state if voters impose a same-sex marriage ban in a possible November ballot measure.

The Washington state Senate has already approved the gay marriage bill, which has the support of Democratic Governor Chris Gregoire, who is pleased with the federal court ruling, her spokeswoman Karina Shagren said.

It shows that time and time again, the public's understanding of marriage equality and the country's acceptance of it seems to be shifting in a positive direction, Shagren said.

Opponents of gay marriage point out that in all 31 states where the question has been put on the ballot, voters have rejected same-sex marriage. They predict Washington state voters would reach the same conclusion.

At the same time, Washington is one of nine states covered by the San Francisco-based 9th Circuit Court of Appeals.

That means if a voter-approved ban on same-sex marriage is challenged in federal court, a district judge would have to look to any relevant precedent set on Tuesday, legal experts said.

ANALOGIES TO CALIFORNIA

If Washington lawmakers approve gay marriage only to have voters later ban same-sex weddings, a judge could find similarities with the situation in California that led to the 9th Circuit decision, Stanford University law professor Jane Schacter said.

For one thing, Washington like California recognizes domestic partnership for same-sex couples, Schacter said.

Washington could be one of the closer analogies, compared say to a state that either doesn't have domestic partnership or never extended marriage (to same-sex couples) in any form or fashion, she said.

Zach Silk, campaign manager for Washington United for Marriage, a group fighting for same-sex marriage in the state, called the appeals court decision an important victory.

The court of appeals there really affirmed what we've been saying all along, which is how powerful marriage is, he said. That marriage is something we should be able to have between two adults who love each other and are committed to each other.

Meanwhile, opponents of same-sex marriage sought to downplay the decision, and said it would help them persuade voters to restrict marriage to unions between a man and a woman.

This decision fires up the base and the resentment that elites, political and judicial, are imposing gay marriage without the consent of the governed, said Maggie Gallagher, co-founder of the National Organization for Marriage.

I think it's going to make it easier, not harder, to get the signatures and to put it to the people, she said.

The New Jersey-based National Organization for Marriage is backing efforts to hold a referendum in November aimed at repealing any Washington law before it would go into effect.

Gay marriage foes in Washington state said they have not yet agreed on how to put the question to voters in November. They could pursue an initiative affirming marriage as between a man and a woman, or they could push a referendum to repeal the law.

In the case of a referendum, the law would be suspended before the public voted, meaning same-sex couples in Washington would not be able to immediately wed, state officials said.

That would set Washington apart from recent history in California, where 18,000 same-sex couples were married during the summer of legalization in 2008.

If you're going to try to distinguish yourself from this case, one way to do so would be to not be in a situation where you're actually repealing marriage licenses that have already been granted, said gay marriage opponent Joseph Backholm, director of the Family Policy Institute of Washington.

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