By Ronnie Cohen
SAN FRANCISCO (Reuters) - California voters favor same-sex marriage by a nearly 2-to-1 margin, a poll showed on Thursday, a month before the Supreme Court is set to hear arguments over a gay marriage ban approved by the state's residents in 2008.
The Field Poll found 61 percent of surveyed voters in California believe gay and lesbian couples should be allowed to wed, the highest level of support the organization has ever found on that question in the state.
The findings represent a shift in public opinion on the matter since November 2008, when 52 percent of voters in California approved Proposition 8 to amend the state constitution to ban same-sex marriage. Leading up to that vote, polls had shown the public narrowly divided on the question.
Defenders of Proposition 8 discounted the random survey.
"Californians voted for (traditional) marriage twice in the only polls that really matter," said Jim Campbell, an attorney for Alliance Defending Freedom, which represents opponents of gay marriage in the case that has reached the U.S. Supreme Court.
Kate Kendell, executive director of the National Center for Lesbian Rights, cited the Obama administration's filing of a brief on Thursday urging the Supreme Court to allow same-sex marriages to resume in California as further evidence of the momentum in favor of accepting gays and lesbians.
Some 18,000 same-sex couples exchanged vows before California voters approved the gay marriage ban in 2008.
Since then, polls have shown same-sex marriage steadily gaining support among Californians and Americans. Nine states and the District of Columbia allow gays and lesbians to marry. Last year Maine, Washington state and Maryland became the first states to approve it at the ballot box.
Age appeared to be the biggest factor turning the tide in favor of same-sex marriage in California. The Field Poll showed 78 percent of voters age 39 and under favored gay marriage, compared to only 48 percent support among voters 65 or older.
The Field Poll was completed between February 5 and February 17 and involved telephone interviews with 834 registered voters, with a margin of error of plus or minus 3.5 percent.
Same-sex couples sought to overturn Proposition 8 with a federal lawsuit, leading to decisions in their favor at the district and appeals court levels. Backers of the ballot measure last year appealed to the U.S. Supreme Court, which is scheduled to hear oral arguments in the case on March 26.
Kendell said she believes the expensive and emotional legal fight heading to the nation's highest court contributed to voter support for same-sex marriage.
"The Proposition 8 challenge was a huge educational vehicle," she said. "The (district court) trial magnificently exposed how ridiculous the arguments against same-sex marriage were."
(Editing by Alex Dobuzinskis, Cynthia Johnston and Martin Golan)