Lawyer and historian Charles Reid, a Catholic, describes in the Huffington Post how he came to change his mind on marriage equality.
While there is no question that marriage equality dramatically departs from what has gone before, I now find support within the same western tradition for expanding the definition of marriage to include loving, committed same-sex unions.....
Where once American marriage law rested securely on Augustinian premises, the rise of artificial birth control and the right of privacy cases have shifted the foundations. As a matter of public understanding, marriage today can only be grounded on love and commitment, not on procreation. As a Catholic, I still understand marriage in my faith tradition to unite the procreative and affective ideals. But as an American citizen, I also know that I belong to a diverse and creative world where a new set of public norms is even now being created.
....Marriage equality is a new departure in history, but that does not mean that we lack all guidance from the past. History, in the form of the story of love itself and the vast treasure-house of human experience relating to it, can serve as our steady and certain teacher.