California's supreme court has backed a ban on gay marriage, ruling six-to-one that a voter-approved proposition defining marriage as between a man and a woman could stand. But the court, which last year had opened the way for same-sex unions, said the roughly 18,000 marriages that took place in the state before the November ban remained valid.
The ban under a voter-approved measure known as Proposition 8 spurred nationwide protests. Gay advocates on the courthouse steps in San Francisco began shouting "Shame on you" as the decision was made public.
Passage of the gay marriage ban last November bucked California's reputation as a liberal trendsetter and sparked national protests by gay advocates and praise from social conservatives. A flurry of pro-gay marriage rulings and votes in Iowa and New England this year had reversed a trend toward banning them in the United States.
Most US states do not allow same-sex marriage, but both sides are gearing up for renewed battle.