61% of young Republican leaning Americans (18-29) support marriage equality. The issue is settled, the trajectory is clear, it is just a few years until it will all be shaken out and boring and stats about people being against gay marriage will be treated with awe and shock.
In 1986, only around 30% of Americans "approved" of interracial relationships -- now about that number have a family member IN an interracial relationship. Things move faster now, and in just a few years, the idea of being against same-sex marriage will seem just as insane about being against interracial marriage.