Partisan divide growing on gay marriage, survey finds

President Obama’s announcement of support for same-sex marriage has changed public opinion on the issue, a new survey shows - but only in the most partisan of ways.

Democrats, and especially liberal Democrats, have become more supportive of same-sex couples marrying since the president made his famous pronouncement in May, according to poll results released Tuesday by the Pew Forum on Religion and Public Life. Latinos have also shifted slightly toward acceptance of same-same marriage.

Across almost all groups, the percentage of people with no opinion has gone down, suggesting that Obama may have prompted some people to make up their minds.

Among Democrats, support for same-sex marriage rose from 59% in April to 65% in the latest poll, conducted from June 28 to July 9. Among liberal Democrats, the increase was a notable 10 percentage points, from 73% to 83%.

Otherwise, opinions have scarcely budged. Neither Republicans nor political independents have significantly changed their views.

“Pretty much however we split it … the change is really focused among Democrats, and especially liberal Democrats,” said Besheer Mohamed, a research associate at Pew.

In its report, Pew noted the increase in Democratic support against the backdrop of recent news that the Democratic Party plans to add support for same-sex marriage to its party platform at the upcoming Democratic National Convention.

The issue will help Obama politically by increasing enthusiasm among his base of liberal Democrats, the poll numbers suggest. Otherwise, it appears to have been a wash, politically.

Viewed with a longer lens, opinions about gay marriage have shifted dramatically in recent years, with overall support rising from 31% in 2004 to 48% today. That is part of a larger rise in the acceptance of homosexuality that has occurred over decades, largely as older Americans, who tend to oppose same-sex marriage, have passed from the scene and been replaced by younger adults who tend to support it. But again, the change has been far more dramatic among political liberals than conservatives.

Overall, support for gay marriage among the general public edged up from 47% in April to 48% in the June-July survey. That is well within the margin of sampling error, which was plus or minus 2 percentage points for the overall group. Still, Mohamed said the growth was consistent with the general, slow shift in support over time.

Republican support rose by just 1 percentage point, from 23% to 24%. And support among independents dropped from 52% to 51%, suggesting that Obama did himself no favors among that political bloc.

There was a notable uptick in support for same-sex marriage among Latinos, another group that will play an important role in the presidential election. Support rose from 47% in April to 51% in June-July.

Among African Americans, both support and opposition rose as more people made up their minds, but the shifts were small – an increase of 1 percentage point in support and 2 percentage points in opposition.

Those results were well within the margin of sampling error, so it’s impossible to attach very much significance to them, other than to say that Obama’s statement didn’t dramatically change African American opinions. (This hardly matters politically, since black support for Obama is about as close to unanimous as political backing can get.)

Also important to note: Gay marriage is not likely to be a game-changer in the election. Only 4% of those surveyed said it was the most important issue determining their vote for president.

mitchell.landsberg@latimes.com