The northwestern US state of Washington may soon permit gay marriage after a favourable vote was cast by a renowned lawmaker.
Mary Margaret Haugen, a Democrat, said she had thought long and hard before deciding which way to cast her vote, which should ensure passage of a bill granting equal marriage rights to gay couples.
"I have very strong Christian beliefs... For me personally, I have always believed in traditional marriage between a man and a woman. That is what I believe, to this day," she said, explaining the decision on her website.
"But this issue isn't about just what I believe. It's about respecting others, including people who may believe differently than I. It's about whether everyone has the same opportunities for love and companionship and family and security that I have enjoyed."
Speaking after hundreds of people attended a debate on Senate Bill 6239, which would allow same-sex marriage, she said she would prefer the issue to be put to a referendum, but did not know if that would be possible.
"So, forced to make a choice, my choice is to allow all men and women in our state to enjoy the same privileges that are so important in my life. I will vote in favor of marriage equality.
"I know this announcement makes me the so-called 25th vote, the vote that ensures passage. That's neither here nor there. If I were the first or the seventh or the 28th vote, my position would not be any different.
She added: "I happen to be the 25th because I insisted on taking this much time to hear from my constituents and to sort it out for myself, to reconcile my religious beliefs with my beliefs as an American, as a legislator, and as a wife and mother who cannot deny to others the joys and benefits I enjoy.
"This is the right vote and it is the vote I will cast when this measure comes to the floor."
Six US states -- Connecticut, Iowa, Massachusetts, New Hampshire, New York and Vermont -- plus the District of Columbia already allow same-sex marriage, but the issue remains highly controversial.
A group of 80 US mayors -- including New York's Michael Bloomberg, Chicago's Rahm Emanuel, Antonio Villaraigosa from Los Angeles and Annise Parker from Houston -- last week unveiled a campaign to win support for same sex marriage.