OLYMPIA, Wash. (AP) – Just 11 years ago, Washington state lawmakers barred same-sex marriage with the passage of the Defense of Marriage Act. This week, that law is on the edge of becoming irrelevant.

On Monday, Gov. Chris Gregoire signed an “everything but marriage” bill that gives gay and lesbian couples all the state-provided benefits that married heterosexual couples have. A referendum effort to overturn the law has already begun.

As a handful of other states, most recently Maine, have legalized same-sex marriage, it seems inevitable that Washington state lawmakers will soon be asked to once again define who can get married.

Sen. Ed Murray, who has spearheaded the domestic partnership expansion effort for the past three years, said that while the marriage debate may still be a few years off, the incremental approach was a strategic plan.

“We needed to have a multiyear discussion with the state on gay and lesbian families,” said Murray, one of six gay lawmakers in the Legislature. “I believe DOMA won’t long be the law of the state because those conversations are changing hearts and minds around the state.”

But Murray, D-Seattle, is quick to caution that just because an almost-marriage law for same-sex couples will soon be on the books, that doesn’t mean the state will embrace same-sex marriage.

“California’s experience should be a lesson to us, not to move before we’re ready,” he said.

Same-sex marriage was legal in California for five months until a state referendum to ban it passed last fall.

And opponents of same-sex marriage in Washington have already filed Referendum 71, which seeks to overturn the latest domestic partnership expansion because they think the bill is too close to marriage.

“This isn’t about benefits, it really isn’t,” said Gary Randall, president of the Faith and Freedom Network. “It’s about redefining marriage.”

The bill with Gregoire’s signature expands on previous Washington state domestic partnership laws by adding such partnerships to all remaining areas of state law where currently only married couples are mentioned. The statutes range from adoption and child support rights and obligations, to pensions and other public employee benefits.

Any benefits that cost the state money, such as pension benefits, are delayed until 2014 because of the budget deficit.

The underlying domestic partnership law, which Murray sponsored two years ago, provided hospital visitation rights, the ability to authorize autopsies and organ donations, and inheritance rights when there is no will.

Last year, lawmakers expanded that law to give domestic partners standing under laws covering probate and trusts, community property and guardianship.

The quick progression of domestic partnership laws in the state came on the heels of a 2006 state Supreme Court ruling that upheld the 1998 law banning same-sex marriage. But earlier that year, a gay civil rights measure passed after nearly 30 years of failure, signaling a change of mindset in the Legislature.

“The culture has changed,” Murray said. “And as the culture changes, the politics changes.”

It’s a culture shift that even opponents recognize.

Shortly after filing the referendum challenge, the Faith and Freedom Network sent out a survey to supporters asking them if they supported the referendum, and if so, how they were willing to support it: financially, by circulating petitions, or by praying.

The survey noted a recent poll they took that found nearly 60 percent of those surveyed between the ages of 18 and 35 supported same-sex marriage.

“I know what we’re up against, I’m not naive,” Randall said.

Randall and his supporters need to get more than 120,500 valid voter signatures by July 25 in order to qualify for the November ballot. And they can’t start circulating petitions until after Gregoire signs the bill and any challenge to the referendum wording is worked out.

If opponents qualify for the ballot, the law is delayed until the results of the November election.

But the referendum effort has already hit a few snags.

The day after it was filed, a prominent opponent of same-sex marriage said he thought it was unwinnable.

“Why fight a battle you can’t win? It will cause you to lose a war you can win,” said Joseph Fuiten, a Bothell pastor who is leader of Positive Christian Agenda. “It will undermine our position when it comes to fighting the marriage battle.”

Fuiten said he and others he’s surveyed believe religious groups should be getting ready to fight any upcoming same-sex marriage effort in the state.

Five states have legalized same-sex marriage: Connecticut, Massachusetts and Iowa through court order; Vermont and Maine through legislative action.

Bills to allow same-sex marriage are currently before lawmakers in New Hampshire, New York and New Jersey.

New Jersey, California, New Hampshire, Oregon, Washington and the District of Columbia have laws that either recognize civil unions or domestic partnerships that afford same-sex couples similar rights to marriage. Thirty states have same-sex marriage bans in their constitutions.

As of this week, more than 5,300 domestic partnership registrations had been filed in Washington since July 2007.

The domestic partnership bill is Senate Bill 5688.