The Heritage's Foundry blog overviews recent developments in the fight to protect marriage:

The institution of marriage has seen better days in America. The question now is how Americans will think about, shape, and participate in marriage going forward. Will Americans seek to strengthen marriage, including through laws and policies that promote the public goods of responsible childbearing and the faithfulness of husbands and wives to each other and their dependent children? Or, will Americans reject the traditional understanding of marriage and replace it with mere government recognition of whatever private arrangements two or more people wish to make?

... As the debate about marriage continues, increasing numbers of Americans will be forced to confront and decide fundamental issues of law, morality, and culture. On the one side of this debate is the view that marriage as one man and one woman is a form of institutionalized bigotry no better than racism. In this view, it is unjust for the state not to bless same-sex unions with both the benefits and label of “marriage.” Private institutions and individuals who object to facilitating or expressing moral support for same-sex marriage could face potential civil liability and discrimination in access to government benefits. Too often, those who disagree with redefining marriage are also subject to public derision and even threats, intimidation, and other harms.