Just a thought, an idea, that is cogitating in my mind, and admittedly, not completely fleshed out yet.
What if we made marriage a religious choice, and the government strictly granted everyone a civil union certificate when two people wanted to spend their lives together? The government would have no role or function in the act of marriage, and strictly grant a certificate of civil union when two people wanted to have the rights of what we now define/call "marriage."
The union of two people by the government would have no religious affiliation. If one wanted a "marriage" ceremony, then one could choose to have whatever ceremony they wanted to, in accordance with their own beliefs.
I wonder if our government strictly granted civil unions, and not the right to marry, or the issuance of marriage certificates -- if the rights of what we now call "marriage" might have a better chance of being granted to all.
Again, just some ramblings/thoughts....