Supporters of Proposition 8, which would outlaw the practice, nose ahead in polls.
In a key vote being watched around the US and beyond, California will revisit on Nov. 4 the question of same-sex marriage. Proposition 8 would outlaw gay marriage by amending the state Constitution to say: "Only marriage between a man and a woman is valid or recognized in California."
The battle over Proposition 8 has been building in recent weeks, with millions of dollars being poured into ads on both sides, and some polls showing rising support for the measure.
Because of the state's size, population, and history of being on the cutting edge in social and cultural movements, the vote may help speed up or slow down similar moves in other states and countries.
"The world is watching this," says Dr. Leo Godzich, president of the National Association for Marriage Enhancement, a marriage education organization based in Arizona. "We have gained a worldwide reputation for exporting social issues to other nations. So, many are watching to see whether we will stand up for what has been a traditional foundation for society."
Gay-rights advocates say the notion of "traditional foundation" is expanding. And they expect that any defeat in California will discourage similar moves to outlaw same-sex unions elsewhere.