SEATTLE (RNS) In the headquarters of Washington United for Marriage, a large collage displays a list of the high-powered sponsors backing the ballot-measure campaign to legalize same-sex marriage in the state.

They include such iconic businesses as Amazon, Google and Nike, as well as most of the state's unions and a long list of religious, ethnic and civil rights groups.

Staffers shuttle in and out of a conference room as they figure out how to deploy 4,000 volunteers and an $8.9 million campaign fund. Polling this fall has shown a healthy lead for Referendum 74, which would uphold the gay marriage law passed earlier this year by the Washington Legislature.

"There is kind of a historical moment at play here," says campaign manager Zach Silk. President Barack Obama delivered a major boost for the movement when he declared his support for gay marriage in May and each week seems to bring word of a major entertainment or sports star joining the cause.

Yet for all of all of the growing clout of the gay marriage movement, he says, this campaign remains a leap of faith.

After all, Silk adds, "32 out of 32 losses is pretty daunting."

He's referring to the fact that voters have rejected same-sex marriage each time the issue has been on the ballot. The question now is whether 2012 is the year when that changes.

In addition to Washington, voters will consider measures to legalize same-sex marriage in Maine and Maryland. In Minnesota, voters are being asked to amend their state constitution to ban gay marriage.

With its relatively low churchgoing population and social libertarianism, Washington may be the state where voters are most likely to approve gay marriage. But opponents say the early polls are deceptive.

Chip White, the communications director for Preserve Marriage Washington, says things will change once its TV ads start.

"We do not need to match the other side dollar-for-dollar to get our message out," said White, whose group has raised nearly $1.8 million so far. And he argues that polls in past elections have routinely overstated voter support for gay marriage.

His group has had strong backing from Catholic leaders as well as many Protestant churches. Its largest donor is the Washington, D.C.-based National Organization for Marriage, which has given $725,000.

Preserve Marriage Washington is hammering away at the idea that same-sex couples don't need additional protections because they currently have all the rights and benefits of marriage under the state's 2009 domestic partnership law.

Instead, letting gays marry, White and other critics argue, would change how society views marriage.

Joseph Backholm, the chairman of Preserve Marriage, repeatedly argues in appearances around the state that children do best if raised by their biological parents and that the state should promote that standard.

If Referendum 74 passes, he said in a recent debate on Seattle's KING TV, "marriage now is entirely about the emotional connection that adults have and not at all about the how this affects children and the environment they are raised in."

That drew a strong rejoinder from state Rep. Jamie Pedersen, D-Seattle, who is raising four sons with his same-sex partner.

"The definition of marriage is staying exactly the same," Pedersen said. "I don't think when the prohibitions on interracial marriage were lifted, for example, that that was a change to the definition of marriage." Instead, he said, it's about who can participate in marriage, which is "the gold standard for protecting families."

Thanks to their big campaign fund -- fattened by an eye-popping $2.5 million donation from Amazon founder Jeff Bezos and his wife MacKenzie -- gay marriage supporters have had the TV airwaves to themselves so far.

But things could look very different once opponents hit the airwaves. In California, activists thought they had turned voters against Proposition 8, the 2008 ballot measure banning same-sex marriage.

Then a late TV advertising campaign appeared to turn the tide by charging that the schools would promote gay marriage to children. One ad showed a young girl coming home to tell her mother, "I learned how a prince married a prince and I can marry a princess!"

White, the spokesman for Preserve Marriage Washington, says opponents fear the same would happen in schools in Washington if Referendum 74 passes. They also believe that businesspeople who refuse to provide services for gay marriages -- such as innkeepers or wedding photographers -- could face legal sanctions.

Gay marriage supporters say the ad is based on a school in Lexington, Mass., one of six states that allows same-sex marriages, which provided a book that promotes gay marriage. And they say that anti-discrimination laws already prohibit businesses from not serving customers based on their sexual orientation.

(Jeff Mapes writes for The Oregonian in Portland, Ore.)