As I said, the argument marriage is a state's rights issue was phony from the get-go. The Left doesn't recognize it and there is prior precedent (polygamy in 1890 Utah) for a federal rule on the issue of marriage. Conservatives delude themselves into thinking the liberals and their gay allies simply want a live and let live arrangement on the subject. The federalism approach would be fine if the other side respected the right of this country to say NO to gay marriage. They don't, which is precisely why a constitutional amendment to protect the institution of marriage has become necessary.
The liberaltarians take the same approach. They secretly WANT sodomite "marriage" (Mostly out of hatred for morality) but they can't say it outright because they will lose whatever conservative claim they still hold onto.
So instead they also retreat to the States right's argument.
The libertarians and democrats want marriage to be perverted, they just can't say it out loud.
You said it brilliantly....too bad the cowards in congress decided to duck and run