I reported yesterday on gay issues being a wedge issue again. Here's a more complete explanation.
Some polls are now reporting support for gay marriage is over 50% (by almost as much as the margin of error). Only five years ago support was only at 36%. Support is higher in all categories, including Evangelicals.
Some dispute these numbers because to counter deeply red states the percentage in states on the verge of marriage (such as Maryland) would need to be much higher than latest polls show.
Just a few years ago gay issues were important only to liberal Dems. The GOP could drive a wedge between moderates and Dem candidates. But now the wedge would split the moderates from the GOP.