I am a Christian. I support same-sex unions.
I think there is a huge need for a change of focus from the supporters of SSU*, that will appeal to Christians directly in a way that switches the angle that is currently obviously not working at all. The solution is to make the issue a “render unto Caesar” issue, rather than an issue about love.
In the passage of Matthew 22:15-22 (quoted here), a cluster of people approach Jesus with the purpose of tripping him up on his own words — but Jesus responds sensibly and dispels their trick by establishing that there is a difference between what is man-governed and God-governed, and that if Caesar demands tax, the tax is paid with coins with Caesar’s face on them.
The biggest problem with the Christian “man and woman” marriage being scripture-prescribed is that the state requires a license for marriage, making marriage become a Caesar issue, rather than a God issue. Before you were able to be married, did you sign a document that you were married under the authority of the State-Of something? Doesn’t the person who conducts the marriage ceremony say, “By the power that is vested in me by the State of—” and therefore, isn’t that marriage therefore a matter of Caesar, and not a matter of God?
An authentic Christian marriage would be an exclusively God-seeking, God-governed union between the two that is under the authority strictly of God and no other.. ESPECIALLY not under Caesar. To suggest that Caesar must reconcile with God’s plan for marriage COMPLETELY UNDERMINES Christ’s teaching that matters of God and matters of Caesar are separate.
By suggesting that marriage is defined as one man and one woman by scripture, Christians seem to suggest that the matter is a God issue — but then they simultaneously claim that Caesar should only allow marriage between one man and one woman, making it a Caesar issue. Christians cannot “serve two masters” (Matthew 6:24) either, according to their own scripture.
As an aside, my personal solution for the problem is to eliminate any government authority over marriage completely, so that the state becomes SILENT on the issue entirely. No marriage licenses and no special treatment for pairs of individuals. Not only is the tax code that benefits people of a specific type of union unfair to gays, but it is also unfair to SINGLE PEOPLE who should be treated equally under the law as married people of any kind. This would admittedly gum up matters of naturalization that rely on marriage between citizens and immigrants (among other subjects), but it would more appropriately align with a constitutionally-sound legal system.
* (using SSU to mean same-sex unions, as a catch-all not limited strictly to gay marriage)