Gabriel Bouys/Emmanuel Dunand/AFP/Getty Images
Comparing The Candidates
McCain: McCain supports a state constitutional amendment banning gay marriage in California, but he opposes a federal ban. On a daytime TV talk show hosted by Ellen DeGeneres, who is openly gay, McCain said: "I just believe in the unique status of marriage as between a man and woman, and I know that we have a respectful disagreement on that issue."
Obama: Obama offers congratulations to newlywed same-sex couples in California and says that they deserve full equality, but he opposes gay marriage. He told a forum on gay rights issues: "I would continue to support a civil union that provides all the benefits to a legally sanctioned marriage."
Ryan Anson/AFP/Getty Images
Rodney Maccarate (left) and James Winstead kiss after exchanging vows in San Francisco on June 17.
For all of the countless times the presidential candidates have laid out their positions on the war, the economy and health care, there is one issue that they haven't talked about much: gay marriage.
For both Democrat Barack Obama and Republican John McCain, it is risky territory, where they have as much to lose as they have to gain.
Even when the Supreme Court of California legalized gay marriage earlier this year, all that came from the campaigns were short, very carefully worded, written statements.
University of Washington professor David Domke, who writes about politics and religion, says that the candidates want nothing to do with gay marriage as a political issue. He argues that is because neither has a clear position on it.
McCain, for instance, supports a constitutional amendment banning gay marriage in California, but he opposes a federal ban. And while Obama offers congratulations to newlywed same-sex couples in California and says that they deserve full equality, he opposes gay marriage. Domke calls their positions "muddled."
"Both have this nuanced 'On the one hand and on the other hand' need-to-explain position, and I think that makes it difficult for either to take a stand," Domke says.
Why The Candidates Are Mum On Gay Marriage
Both candidates also have the difficult task of trying to appease their bases, while also reaching out to the center.
Obama, for example, is trying to make a play for some evangelical Christians who traditionally vote Republican. At the same time, he needs to avoid alienating liberals. That presents a challenge, such as when Obama participated in a forum on gay issues in 2007.
If elected president, Obama told the panel, "I would continue to support a civil union that provides all the benefits to a legally sanctioned marriage." Panelist Joe Solmonese, a gay rights advocate, challenged Obama's answer, suggesting it was a policy of separate but equal.
McCain skates a similarly fine line in that he needs to reassure the conservative "value voters" who have publicly doubted his commitment on social issues. At the same time, he cannot afford to scare away moderates and independents.
When McCain did confront the issue of gay marriage on The Ellen DeGeneres Show, the tension seemed palpable.
"I just believe in the unique status of marriage as between a man and woman, and I know that we have a respectful disagreement on that issue," he told host DeGeneres, who is openly gay.
The 'Enthusiasm Gap'
Political consultant Doug Hattaway has advised many Democratic candidates on gay issues. He says candidates ought to steer clear of same sex marriage this year simply because it's relatively unimportant to voters.
"Bottom line is, I think that both candidates feel squeezed. So the best approach is to talk about the economy," Hattaway said.
On the campaign trail that's exactly what the candidates have been doing.
And Domke says gay marriage will not have the kind of impact this year as it did in 2004. That year, the issue energized social conservatives, helping to boost President George W. Bush at the polls in key battleground states such as Ohio.
Tom McClusky of the Family Research Council says that if McCain will not bring up gay marriage, conservatives will. "The senator, so far, has not been a candidate who motivates the grassroots," he said. "But these issues motivate the grassroots and will get the people in churches and people who care about these issues not only out to vote, but hopefully, bringing their friends along."
The question is whether gay marriage as an issue could ever be enough to close what analysts are calling the "enthusiasm gap."
Polls show Democrats and progressives are far more energized and excited to vote for Obama than Republicans and conservatives are to vote for McCain.
And that passion may drive more voters to the polls this November than the issue of gay marriage ever could.