The Marin County Republican Party has endorsed same-sex marriage.
The vote, one of the first of its kind, does not change the state or national Republican Party's opposition to same-sex marriage.
But experts say it's a sign that same-sex marriage is gaining new support.
The group's chairman says his party's opposition to same-sex marriage has been a significant obstacle to attracting new members.
Washington D.C.'s local GOP organization also endorsed same-sex marriage last year.