DALLAS This week's start of gay marriages in California has pushed a hot-button social issue into the U.S. presidential campaign, but will it be a sideshow or a main event?
When voters in California and Florida choose between presumptive Democratic nominee Barack Obama and Republican John McCain in November, they will also be asked to weigh amendments to the state constitutions seeking to ban same-sex marriage.
Such ballot initiatives played a key role in President George W. Bush's 2004 re-election as they galvanized the Republican Party's conservative Christian base.
But several key things are very different this year.
The first is McCain. In sharp contrast to Bush, the Arizona senator is regarded with suspicion by many conservative evangelicals because of his past lack of support for a federal ban on same-sex marriage and other "liberal" offenses.
"McCain is a Republican nominee who has to appeal to the base but he is much queasier on social issues with the exception of abortion. He is much less confrontational on things like gay marriage," said Cal Jillson, a political scientist at Southern Methodist University in Dallas.
The evangelical movement, which counts one in four U.S. adults among its ranks, has also undergone change since 2004 as it broadens its biblical agenda beyond abortion and gay marriage to embrace issues like global warming that were previously seen as causes of the left.
BACK ON THE RADAR
Neither Obama nor McCain have made gay marriage a centerpiece of their campaigns. Obama, an Illinois senator, has said states should make their own decisions on marriage but believes "same-sex couples should enjoy equal rights under the law."
The California Supreme Court has put the issue on the 2008 electoral agenda just when it seemed to have faded far behind concerns about a recession, the housing crisis, soaring fuel prices and the war in Iraq.
Same-sex weddings kicked off in California on Monday after a ruling by the court paved the way for their recognition. And unlike Massachusetts, the only other state where gay marriage is legal, California will wed couples from other states.
With or without a staunch religious conservative in the White House race, this has the "Religious Right" seeing red.
The Southern Baptist Convention, America's largest evangelical denomination, last week called on its 400,000 members in California to support the amendment against gay marriage in November.
But California is viewed as safely Democratic and not seen tilting Republican because of the issue, although voters could reject gay marriage in the ballot initiative.
The same cannot be said of Florida, which has a large evangelical community and where the presidential contest is shaping up to be tight.
According to the latest Quinnipiac University Swing State poll released on Wednesday, Obama's lead over McCain in Florida is 47 percent to 43 percent -- hardly a wide margin.
"Florida is close enough ... that energized social conservatives could affect the outcome there," said Jillson.
Social conservatives are gearing up in Florida, where the amendment needs 60 percent support by voters to pass.
The issue could also heat up elsewhere if a couple from Kansas or some other heartland state gets married in California and then demands that local authorities recognize their union.
"This will have a strong galvanizing effect for the Republican base and that is the kind of thing that the McCain campaign needs," said Michael Lindsay, a political sociologist at Rice University in Houston.
Evangelical opposition to gay marriage is rooted in a reading of scripture that sees same-sex relations as sinful. Social conservatives also see it as a threat to the traditional family and, by extension, their vision of a functioning society.
A nationwide survey by the Pew Research Center from May 21-25 found the issue gaining prominence among Republicans.
It showed that 41 percent of Republicans surveyed said gay marriage would be very important in their voting decisions, up 14 percentage points from last fall.
Analysts said there is a sense of urgency on both sides of the debate because gay marriage has momentum.
The Pew survey found 49 percent of Americans oppose gay marriage and 38 percent are in favor. Pew noted this was the first time since the question was posed more than a decade ago that a majority of Americans did not oppose same-sex marriage.
In July 2004, for example, Pew found 56 percent opposed to such unions and 32 percent in support.
Combined with what social conservatives see as "activist courts," there is a sense among the right wing that its position needs to be legally entrenched -- which can motivate its supporters to get out and vote.
"I think among conservative Republicans there is a sense that constitutional amendments are the only way to secure their position," Lindsay said.
(Editing by Mary Milliken and John O'Callaghan)