But supporters said that it is simply an issue of discrimination to reject the referendum.
"I think this issue has kind of been blown out of proportion," said opponent Isaac Becker. "I do believe that marriage is just a term that should be used men and women, not for same-sex couples."
"Some people can disagree with it, some people can agree with it," said supporter Tobias Slaton. "But you're basically telling someone that they cannot enjoy the same liberties and happiness that a heterosexual couple would enjoy and that's discrimination so I don't believe in it."
Washington's current law prohibits marriage of same-sex couples. However, it allows them to enter into a state-registered domestic partnership if the two people are over 18, live together, are not closely related, and aren't already married to other people.