How do you make the case for same sex marriage?

[TaraJo]

If marriage, at heart, is a religious ceremony, why does the government perform marriages? There should be a separation between church and state and that separation can't exist if people are performing religious ceremonies to gain state rights.

We are in different countries. There's no separation of State and Church in my country. My church is called the Established Church because it's the state church.

I'll give you that; My argument is based on United States law. If I were in the UK, I would have to tweak that part of the argument. However, I'm making the argument as it applies to American law and we do have separation of church and state.