Gov. Christine Gregoire signs the marriage equality bill that voters approved on Election Day.

Washington United for Marriage today announced victory in its fight to uphold marriage equality in Washington state, with 52% of Washington voters approving Referendum 74, and just 48% opposed.

With this vote, Washington becomes the ninth state -- along with the District of Columbia -- to legalize same-sex marriage, and among the first to do so at the ballot box. In a landslide victory for equality on November 6, voters in Maine and Maryland also voted to legalize marriage equality, and Minnesota voters rejected a proposed amendment to the state constitution that would have banned same-sex marriage.

"This is a clear win," said WUM campaign manager Zach Silk in a statement. "We have run the numbers every which way, and we can now confidently say that we have won. This is an historic day for Washington, an historic day for our country and, most of all, for families across the state who have dreamed of this day and the wedding celebrations to come."

With 60% of the votes counted, WUM declared victory upon comfirming that it was stastically impossible for equality opponents to overcome the percentage of ballots already cast in favor of Washington's same-sex marriage bill, which was signed by Democratic Gov. Christine Gregoire in February.

"Washington voters sent a resounding message that nothing less than marriage is full equality for gay and lesbian couples," said Human Rights Campaign President Chad Griffin in a statement. "This victory rounds out a landslide sweep of all four marriage ballot measures this November."

According to HRC and WUM, the broad coalition to protect marriage equality raised $12.3 million to uphold the law. Because Washington votes entirely by mail-in ballot, the final results are still being tabulated.

Just in time for Valentine's Day earlier this year, Gregoire signed into law a marriage equality bill that was introduced in the legislature just weeks before. Gregoire told supporters that February 13 would be "a day that historians will mark as a milestone for equal rights," when Washington "finally said yes to marriage equality. The sky-will-fall rhetoric is simply not true."

But equality opponents begged to differ, and within days of the bill's passage began to gather signatures to put the issue to the voters by way of a November referendum. Ultimately, the anti-equality group secured more than enough signatures to refer the issue to voters, who will see the question on their ballots as Referendum 74. In 2009, Washington legalized an expansive domestic-partnership law heralded by many as "everything but marriage."

The language of the this year's measure reads as follows: "The legislature passed Engrossed Substitute Senate Bill 6239 concerning marriage for same-sex couples, modified domestic-partnership law, and religious freedom, and voters have filed a sufficient referendum petition on this bill.

"This bill would allow same-sex couples to marry, preserve domestic partnerships only for seniors, and preserve the right of clergy or religious organizations to refuse to perform, recognize, or accommodate any marriage ceremony. Should this bill be: Approved or Rejected."

POLLS
Initial polling showed a strong majority in support of marriage equality, but as the election neared -- and attack ads hit the airwaves -- those results tightened. In May, an independent poll found that 54% of voters approved of marriage equality, with just 33% opposed. While most polls leading up to the election saw support for the freedom to marry above the 50% margin, the most recent Elway poll, conducted from October 18 to 21, found support for Referendum 74 at just 49%, with opposition to marriage equality among likely voters at 45%.

MONEY
Washington United for Marriage, the coalition working to protect marriage equality in Washington, vastly outspent its opponents, Protect Marriage Washington. According its own press release, WUM raised $12.3 million to protect marriage equality, gathered from more than 27,000 donors -- 80% of whom hailed from Washington. The most frequent contribution made by supporters was $25, WUM announced. WUM also secured several major financial donations, including a half-million-dollar contribution from Bill and Melinda Gates.

A Seattle Post-Intelligencer article noted that the antigay PMW has taken in $2.1 million and spent just under $1.5 million, according to PMW's filings with the state Public Disclosure Commission. Of that money, the Human Rights Campaign reports that more than 55% came from the Catholic Church and the Catholic-affiliated National Organization for Marriage. The Catholic Church and its affiliate the Knights of Columbus donated a combined $260,000 to PMW, whereas NOM donated $675,939 to anti-equality efforts in Washington, according to HRC.

ENDORSEMENTS
President Obama endorsed Referendum 74 along with other marriage-equality-adjacent bills, and WUM secured several major corporate endorsements. Online travel giant Expedia came out in support of Referendum 74 in September, and by October had released a touching ad in which a real-life father flies across the country to support his daughter in her same-sex wedding, with the tagline "Find Your Understanding." WUM also secured endorsements from Starbucks, Microsoft, T-Mobile, REI, Nordstrom's, Google, Nike, and more than 500 other business, political, non-profit, labor, and faith communities.

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WUM came out of the gates swinging, with an early $5 million ad buy reserving time on TV screens across the state to stump for marriage equality. The coalition's numerous ads highlighted support for marriage equality in faith communities, by parents of gay and lesbian Washingtonians, and elected officials, including Tacoma mayor Marilyn Strickland and GOP state senator Steve Litzow.

But when PMW released a version of a misleading ad -- airing in all four states considering marriage legislation -- claiming that schools will be forced to teach children about same-sex marriage if the state passes marriage equality, the pro-equality camp hit back with an ad featuring parents of a gay son lamenting the fact that their son wouldn't be able to marry the person he loves.

PMW's oppositional ads generally recycled old, discredited tropes about the dangers of "redefining marriage" and violations of "religious freedom," often featuring out-of-state actors who alleged their rights had been violated when committed gay couples were allowed equality under the law. In perhaps one of the opposition's most insidious efforts, PMW actually purchased "likes" on Facebook from Thailand and Indonesia, artificially boosting the group's apparent support on the social networking site.

Correction: An earlier version of this article incorrectly attributed the $500,000 donation for marriage equality to the Bill and Melinda Gates Foundation. That contribution was a personal donation from the Gates themselves, not from their non-profit.