On election night, as gay marriage supporters gathered at the Westin in downtown Seattle to await news of a victory, Washington Governor Christine Gregoire took the stage.
Fighting to hold back tears, she called marriage equality the "defining civil rights issue" of a generation.
Just moments before she spoke, voters in Maine and Maryland passed ballot measures legalizing same-sex unions. A constitutional ban on the ballot in Minnesota had failed.
Days later, as ballots continued to be counted, Washington state's Referendum 74 would pass, making voters here among the first in the country to give gay and lesbian couples the right to wed.
"I think it is hard to say 'Why does culture switch in the period of a couple years?' said Jennifer Self, director of the Q Center at the University of Washington. "One day 50 percent of the people are saying 'No, no, no,' and then you go over that edge..."
She believes support for gay marriage has reached a critical turning point.
"I really think that there has been, over the last 20 years, a shift in people's understandings of gay and lesbian people," Self said. "And, honestly, there's been a whole lot of money poured into this campaign, at the national level and at local levels."
Supporters of gay marriage raised roughly $13.6 million for the R-74 campaign, compared to the $2.7 million brought in by their opponents, Preserve Marriage Washington.
"If you have enough money to put into a campaign you can sway public opinion and actually shift culture," Self said. "It's a combination of very successful campaigns, that needed to happen or these wouldn't have passed, along with decades of cultural shifting."
Joseph Backholm, who chaired the campaign against R-74, said the outcome would have been different had the financial numbers been different. He rejects the idea that there has been a cultural shift in how Americans view same-sex marriage.
"We were outspent by $10 million in a really blue state and it was a really close election," he said. "For my four children, I am specifically necessary in their lives and their mother, who is my wife, is specifically necessary in their lives. That was true 1,000 years ago, it is true today and it will be true 1,000 years from now."
Nine states - New York, Connecticut, Iowa, Massachusetts, New Hampshire, Vermont, Maine, Maryland, Washington - and the District of Columbia now allow same-sex couples to wed.
Self predicts many more will follow as a result of this year's election, and it won't be long, she argues, until the federal government's Defense of Marriage Act, or DOMA, will fall.