But that was the South. And that was before President Obama spoke out for same-sex marriage. Since then the chorus of support has grown louder, with the N.A.A.C.P., for example, formally joining in. Funding for marriage-equality campaigns has grown stronger. And polls show a trend in the direction of greater approval for same-sex marriage, which a very slight majority of Americans, in some surveys, seem to endorse.

"There's tremendous momentum," said Brian Ellner, a leading marriage-equality advocate and co-founder of a new social media campaign, The Four 2012, to raise resources for, and awareness of, the state referendums. "Everything is aligned for us to win this year."
