By Nicole Neroulias
SEATTLE (Reuters) - Washington state Gov. Christine Gregoire plans to sign legislation on Monday legalizing gay marriage, making the state the seventh in the nation to recognize same-sex matrimony.
A statehouse signing ceremony in Olympia was slated for 11:30 a.m. But the measure, which won final legislative approval last Wednesday in a 55-43 vote in the state House of Representatives, would not take effect before early June.
The Washington state law, once signed, would amount to another key victory for proponents of gay marriage after a federal appeals court declared a voter-approved gay marriage ban in California unconstitutional last week.
Opponents of the Washington measure have vowed to seek its repeal at the polls in November, but they cannot begin collecting signatures for a petition to repeal the bill by referendum until it is signed into law.
Democrats, who control both legislative bodies in Olympia, accounted for the lion's share of support for the bill. The stage for swift passage of the measure this year was set after Gregoire, a Democrat in her last term of office, said last month she would endorse such a law.
Several prominent Washington-based companies employing tens of thousands of workers in the state have supported the bill, including Microsoft, Amazon and Starbucks. Opponents were led by Catholic bishops and other religious conservatives.
Supporters of same-sex marriage are pushing similar statutes in Maryland and New Jersey. The state Senate in Trenton was expected to vote on a gay marriage bill on Monday, though Republican Governor Chris Christie has vowed to veto it if it reaches his desk.
A referendum to legalize gay marriage in Maine has qualified for the November ballot there. Six other states already recognize gay marriage -- New York, Massachusetts, Connecticut, Vermont, New Hampshire and Iowa -- as does the District of Columbia.
Gregoire said after the bill won legislative approval that Washington state would "no longer deny our citizens the opportunity to marry the person they love."
"We tell every child of same-sex couples that their family is every bit as equal and important as all other families in our state," she said in a statement issued after last Wednesday's House vote.
Still, the measure cannot take effect before June 7, three months after the conclusion of the legislative session.
In the meantime, opponents of same-sex matrimony have said they would seek to overturn the legislation via one of two ballot measures -- a referendum for repeal or an initiative defining marriage as the exclusive domain of heterosexual couples.
If a repeal referendum qualifies for the November ballot, the gay marriage law would be suspended until the certification of election returns in December, before it is either repealed or goes into effect.
But qualification of a proposed initiative defining matrimony as restricted to one man and one woman would not, in and of itself, prevent gay marriages from proceeding under the newly passed statute starting on June 7.
It remains unclear whether gay weddings performed in the interim would be nullified if an initiative were to pass in November.
(Writing by Cynthia Johnston; Editing by Steve Gorman and Dan Burns)