Maggie Gallagher has a helpful article at The Public Discourse about the aims of the gay rights movement. She warns about the conflict that will come to those stand for traditional marriage:
Advocates of gay marriage are not slow to use any lever of power, including government, to impose their new morality on America. The primary goal of the existing gay marriage movement is to use cultural, social, economic, and political power to create a new norm: marriage equality. The governing idea behind “marriage equality” is this: there is no difference between same-sex and opposite-sex unions. If you see a difference, there is something wrong with you. “You’re a hater, you’re a bigot, and you need to be fired!” Watch out.
In other words, if you support traditional marriage, the activists are not simply going to live and let live. They are not going to let up until standing for marriage is seen to be the moral equivalent of defending slavery.