Same-sex couples in California may not need the U.S. Supreme Court to give them the legal right to marry — the state’s voters now overwhelmingly approve of gay nuptials, marking a dramatic shift in attitudes on the issue over the past few decades, according to a new Field Poll.

The latest poll, released on Wednesday, shows that 61 percent of California voters approve of same-sex marriage, more than double the support when the question was first posed in 1977. Only 32 percent of those polled disapprove of same-sex marriage now.

The support is up markedly from 2008, when voters approved Proposition 8 by 52 percent to 48 percent, restoring California’s ban on same-sex marriage. At that time, the Field Poll showed 51 percent of voters approved of same-sex marriage, well below the findings from the survey conducted earlier this month.

The most recent poll also shows a dramatic increase in support since 2004, when gay marriage burst onto the California political landscape as a result of former San Francisco Mayor Gavin Newsom’s short-lived attempt to issue marriage licenses to same-sex couples. Nine years ago, 44 percent of the state’s voters approved of same-sex marriage.

While California gay marriage advocates are hoping the Supreme Court soon strikes down Proposition 8 and forbids states from banning same-sex marriages, the Field Poll indicates they may fare better at the ballot box if they lose the legal battle. The Supreme Court will hear arguments in the legal challenge to Proposition 8 on March 26 and rule by June. The poll found 60 percent of voters consider the court case either “very important” or “somewhat important.”

Eight states have legalized same-sex marriage, and advocates say polls suggest more will follow.

“Time is on our side on the issue,” said John O’Connor, executive director of Equality California. “Every time a poll comes out we see an increase in public support.”

Gay marriage opponents were not swayed by the recent poll. Andrew Pugno, legal counsel for ProtectMarriage.com, the main backer of Proposition 8, said “polls on this issue have been historically misleading.”

And Randy Thomasson, president of SaveCalifornia.com, said the definition of marriage shouldn’t be based on opinion polls.

“The truth has always been, and will always remain, no matter what any law says, that if you don’t have one man and one woman, you don’t have real marriage,” he said.

The Field Poll, however, found support for gay marriage is increasing across all demographic groups, with younger voters leading the way. Seventy-eight percent of voters between the ages of 18 and 39 approve of same-sex marriage, compared to 48 percent of those 65 and older.

Manuel Martinez, a 47-year-old Campbell resident who participated in the poll, not only approves of same-sex marriage, but he’s also hoping the Supreme Court strikes down Proposition 8 so he can wed his partner, Russell.

The declining resistance to gay marriage shows that people are “saying give it to them, be done with it,” Martinez said.

Republicans and political conservatives continue to disapprove of gay marriage, the poll shows, although Republican support has grown from 26 percent in 2010 to 39 percent now.

Robert DeSoto, a Republican from Danville, strongly opposes same-sex marriage, although he supports equal benefits for gay and lesbian couples. He hopes the Supreme Court upholds Proposition 8.

“I believe same-sex couples can have all the rights of married couples, but I believe marriage is a biblical institution that is between a man and a woman,” he said.

Howard Mintz covers legal affairs. Contact him at 408-286-0236 or follow him at Twitter.com/hmintz.