Some gay-rights advocates said Obama's move wasn't particularly courageous or pioneering. Former Vice President Dick Cheney and former first lady Laura Bush are among prominent Republicans who have endorsed same-sex marriage.
A new AP-GfK poll of adult Americans showed Obama with a 21 percentage point lead over Romney on the question of who is most trusted to handle "social issues such as abortion and same-sex marriage."
Starting last year, small majorities of Americans told the Gallup poll that gay marriage should be legal.
Republican consultant Matt Mackowiak said Obama needs to fire up liberal potential donors and seems willing to worry about blue-collar workers in swing states later.
"Obama's decision will hurt him in Indiana, Virginia, North Carolina, rural Pennsylvania, northern Florida, rural Missouri, lots of places that he needs," Mackowiak said. "The map just improved for Mitt Romney."
Perhaps. But few Democrats expect Obama to try hard in Indiana and Missouri. And he can easily win re-election without North Carolina and Virginia, provided he carries Ohio or Florida and doesn't lose states such as Michigan, Wisconsin and Pennsylvania.
Jen Psaki, a former Obama aide, said Democrats might be able to turn the issue against Romney.
"In his pursuit of acceptance by conservatives," she said, "Mitt Romney's support for a federal marriage amendment would be the first time we amended the Constitution to deny Americans equal rights, which is alarming to most people."
It seems highly unlikely that the U.S. Constitution will be amended to ban or safeguard same-sex marriage. Obama's comments Wednesday were more symbolic than substantive. But symbols matter when they come from the White House.
Democrats believe the president has his finger on the pulse of a fast-changing society. From a presidential election standpoint, opposition to same-sex marriage will matter only in the handful of states truly up for grabs on Nov. 6. If that opposition is sufficiently intense and organized, it could deal a surprising blow to the president.
For now, Romney, Boehner and mainstream GOP strategists seem more willing to focus on the struggling economy.
EDITOR'S NOTE — Charles Babington covers national politics for The Associated Press.
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