Amazon.com founder and CEO Jeff Bezos and his wife, MacKenzie, announced Friday they are donating $2.5 million to the campaign to defend Washington's same-sex marriage law.
With the gift, Washington United for Marriage has raised more than $5 million for its referendum campaign.
"It's a game changer for us," said campaign manager Zach Silk in Seattle. "It puts us in unique position to win."
But, his group is still the underdog, he said. In 32 previous elections nationally, same-sex advocates have lost.
The Washington election may be the turning point, thanks in part to the Bezos' generous donation, Silk said.
"They understand what's at stake for Washington families and what's at stake for the country," he said. "We're at a tipping point, and they really understand this is an historic moment, and they want to be on the right side of history and want to make history."
Last month Microsoft CEOand co-founder Bill Gates each donated $100,000 to support the law.