Republicans said that dwelling on the issue could become a distraction in the effort to win back the House or Senate from Democrats this fall. At a meeting of the Republican National Committee in Kansas City, Mo., several party leaders and strategists said it would be a mistake for the midterm election campaign to suddenly become focused on gay marriage, immigration or other hot-button issues. The only path to winning control of Congress, they said, rested on making an economic argument.

“This election needs to revolve around five issues: taxes, spending, the economy, jobs and debt,” said Ron Nehring, chairman of the California Republican Party. “That doesn’t mean that other issues aren’t important — they are important — but the first issue on the minds of people is the economy.”

Yet, the dread over the same-sex marriage issue was almost palpable as Mr. Obama’s senior adviser David Axelrod tried to explain on MSNBC on Thursday that Mr. Obama opposed same-sex marriage, “But he supports equality for gay and lesbian couples, and benefits and other issues, and that has been effectuated in federal agencies under his control.”