CNN Politics:

Same-sex marriage could become a nettlesome issue for Democrats this election year. On Wednesday the Chair of the Democratic Convention, Los Angeles Mayor Antonio Villaraigosa, said he believes same-sex marriage should be included in the Democratic Party platform but the Obama campaign is trying to put the issue off to another day.

Democrats are divided over how to handle same-sex marriage at the Democratic convention. Six states plus the District of Columbia now allow same-sex marriage, and some Democratic activists are pushing for its inclusion in the party platform. But the president has not come out in support of same-sex marriage and has said his position on the issue is "evolving."

...The president's campaign is counting on wealthy gay donors to help fuel their fundraising drive. Gay and lesbian donors contributed nearly $1.5 million at just one recent fundraiser.

... It would be hard not to imagine a measure of the campaign's caution on this issue comes from their concern about appealing to socially-conservative swing voters in an election year.

But many gay and lesbian activists aren't in the mood to be political or patient on the issue. One group pressing for the president's self-described evolution to speed up is called Freedom to Marry. They've gathered support from nearly two dozen Democratic U.S. senators for inclusion of same-sex marriage language in the Democratic Party's platform at the convention.