According to the new CBS/NYT poll, most Americans believe the president came out for same-sex marriage for reasons of politics, not principle. And what do you know, Romney’s edged ahead of Obama since the announcement:

A month ago, The Times/CBS News poll showed the two tied at 46 percent each; the latest survey had the Republican challenger at 46 percent to the president’s 43 percent, an edge that was within the margin of sampling error of plus or minus 4 percentage points.

Mr. Obama’s vulnerable standing in the poll came despite rising optimism about the economy. About a third of voters said it is very or fairly good, the most since January 2008, and more than a third said it is getting better, compared with a quarter who said it is getting worse. Jobs and the economy remain by far the most dominant issue, with 62 percent naming it their top priority and 19 percent their second highest. By contrast, just 7 percent chose same-sex marriage as the most important issue and 4 percent the second-most important.

While most respondents said the candidates’ position on the issue would not affect their vote, about four in 10 said it would, and that played against Mr. Obama.

Yeah, with that move, Obama annihilated conservative Christian unease with Romney’s Mormonism. A very slight majority of Americans may favor same-sex marriage, but the overwhelming majority of Americans aren’t going to let it affect their vote, the Times poll shows. The question is, are there more passionate people in favor of gay marriage on the right, or on the left? The data indicate the momentum is on the right. This poll also suggests to me that Romney was right not to make too big a deal of this issue last week, when Obama made his announcement. Conservative Christians know what the score is, and don’t have to be convinced that on the issue that matters most to many of them — religious liberty and same-sex marriage — Romney will be a thousand times better than Obama. Romney should just keep talking about the economy.