It seems to me that in assessing the possible political mileage a politician might get out of assuming this or that stance on this or that issue, one has to also look at the way he comes to his position.
You'll recall that Obama said, from the time we first heard of him, that his views on gay marriage were 'evolving.' It seems to me that that word, 'evolving' is a good one. I bet it makes 'Independents' comfortable, because Independents, allegedly, do not like right or left extremism. To say that one's views on this or that are 'evolving' shows reasonableness and a willingness and ability to grapple with complexity.
Also, this is different that what even Mitt Romney's fellow Republicans have accused him of, which is 'flip-flopping,' which is seen as nakedly political, I mean POLITICAL!
The trend in America, I would say is toward more and more tolerance and a greater and greater appreciation of diversity. Though, we must note that the North Carolina legislature passed this... resolution, or whatever you call it, specifically defining marriage as a union between a man and a woman.
I guess my point is that everything a politician does is going to both hurt him here and help him there. Which effect will be greater remains to be seen.
Take it easy.