One of the most insightful commentaries I have seen on this subject, period. "Render unto Caesar that which is Caesar's, and unto God that which is God's." Marriage was first a religious act and later became a legal act. Separate the two. Marriage have two components - a religious union and a legal union. That way legal unions can be defined to be identifical for everyone, regardless of the gender of the parties being united - equal treatment under the law - while marriages can be defined by the churches. And if some churches choose to unite two people of the same sex in what they want to call a marriage, the state should have nothing to say about it.