When it comes to money, the fight over the state’s same-sex marriage law is a surprisingly one-sided contest.

Washington United for Marriage, the coalition leading the fight to make gay marriage legal in the state, has hauled in almost 14 times more money than those opposed.

As the coalition launched its first statewide television ad last week urging voters to approve Referendum 74, its opponents had raised too few dollars to muster a response on the airwaves.

And if fundraising doesn’t pick up soon, Preserve Marriage Washington, the group opposing gay marriage, may be unable to mount much of any ad campaign in the 51 days left before the Nov. 6 election.

“Would we like to have more? Absolutely,” said Chris Plante, campaign manager for Preserve Marriage Washington. “We do need to get our message out and time is running out.”

As of Friday, seven political committees had raised a combined $8.1 million to convince voters to approve the ballot measure. Washington United for Marriage hauled in most of it, $7.4 million, and is looking to bring in a couple million more.

“We can never let our opponents have more control of the airwaves or resources to talk to people than we do,” said Zach Silk, campaign manager for Washington United for Marriage.

Preserve Marriage Washington, meanwhile, has collected $550,000 in cash and in-kind contributions.

“We’re not trying to match them dollar for dollar,” Plante said. “We never thought we could do that.”

It’s far below the $4 million goal set by Preserve Marriage’s leaders at the outset of the campaign.

Referendum 74 asks voters whether they want to approve or reject the law signed by Gov. Chris Gregoire in February allowing same-sex couples to marry. If it is approved, the law will take effect once the final vote is certified.

Since 1998, there have been nearly three dozen votes around the country on the definition of marriage. Not once have voters approved making it legal for gay and lesbian couples to wed.

The referendum in Washington made the ballot after opponents gathered more than 240,000 signatures on petitions. Preserve Marriage Washington, a coalition of social conservative and faith-based groups, led the effort but it’s been unable to cash in on the enthusiasm for signature-gathering.

Silk said it is “surprising” to see the opposition’s low fundraising total but “we know that their national allies have deep pockets. We expect them to come in with millions of dollars at the end.”

Plante isn’t so sure. The Rhode Island man is on loan from the National Organization for Marriage, which provides funds and expertise to campaigns against same-sex-marriage around the country.

NOM’s resources are stretched this fall as voters in Maryland, Maine and Minnesota also are considering marriage-related measures.

“We expected fundraising would be difficult,” Plante said. “We don’t expect seven-figure checks from national groups. If we get a couple hundred thousand in checks that would be great.”

Meanwhile, early on, well-known names gave handsomely to Washington United for Marriage, which includes social, civic, religious, business and labor groups.

Microsoft Corp. CEO Steve Ballmer and co-founder Bill Gates each donated $100,000 in June. And in late July, Amazon.com founder and CEO Jeff Bezos and his wife, MacKenzie, contributed $2.5 million, an amount Silk deemed unprecedented and a game-changer.

Plante said his group noticed an uptick in small dollar donations following the Bezos’ move.

“We were able to leverage that,” he said. “When elites start trying to tell Washingtonians how to redefine marriage, Washingtonians don’t like it.”

As of Friday, Washington United for Marriage had received 11,991 donations compared to 1,488 for Preserve Marriage Washington, according to information on the Public Disclosure Commission website.

Washington residents accounted for roughly 80 percent of the money given to supporters and 95 percent to opponents.

“This is the kind of campaign Washingtonians are going to deliver and that’s exciting,” Silk said.

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com.

What the new law does

•Defines marriage as between two persons, rather than between a man and a woman. This law lets couples of the same sex marry if both persons are at least 18 years old.

Converts registered same-sex domestic partnerships into marriages on June 30, 2014, unless the couple marries or dissolves its partnership before then.

Allows religious officials to refuse to conduct marriages of same-sex couples without fear of being sued.

Allows religious organizations to refuse to provide facilities, services, or goods for a wedding ceremony or celebration without fear of being sued.

Permits same-sex couples from other states with valid civil unions or domestic partnerships to marry here.

Makes the law gender-neutral in the saying of vows. Couples getting married would say that “they take each other to be spouses” rather than “they take each other to be husband and wife.”