"... we've been sliding down it for 126 years and counting." I find nothing in that observation with which to disagree, but I'd apply it in a much broader context than marriage.
Please, do not misunderstand, I appreciate and value your comments, but am somewhat unconvinced that social or religious constructs really deserve to be considered "fundamental". Particularly ones with so apparently malleable a definition as marriage.
Clearly, in the context of United States case law, you make an unassailable point.
... considering marriage a "fundamental right" would seem a slippery slope. Does an atheist have a fundamental right to be ordained a priest?
To be clear, I think Eich was scapegoated, but am of the opinion it is unfair to deny marriage to gays. I am only concerned here with what seems to me to be excessively broad definitions and the fallout that may result.