Is Marriage Unconstitutional?

This began as a comment at The Conservative Sociologist in response to her reaction to the GMM (Gay Marriage Movement).  She isn't opposed, but finds the logic and media presentation to be flawed and annoying - she writes an interesting blog, you should check it out.

What I said was:

What I rarely see discussed is the unconstitutional nature of government regulated marriage in the USA.

In English Common Law (the law of the land when what would become the USA was still British colonies) the State is the Church and thus there is no conflict between the governments regulation and sanction of an expressly religious ceremony. The US Constitution explicitly forbids government sanction or recognition of religion. On its face, this would seem to make (federal of a certainty and arguably state as well) government involvement in marriage unconstitutional as a matter of constitutional prohibition.

Making this all so much about anything other than the gender of either participant is the acknowledged transfer of ownership of real property (to include at least one of the participants for the historical purists amongst us) that is part and parcel of the religious ceremony in contention. I don't know about a crisis necessarily, but it is certain that no government will waste an opportunity to claim taxes and fees so I don't expect the Supreme Court to take up this issue any time soon.

Of course, anyone seriously advancing this argument can be certain pretty much everyone will have the knives out in response ... literally; virtually all of human society bases property rights and law on this explicitly religious arrangement, whatever particular religion may be the facilitator.

To be constitutionally consistent in the USA, marriage would have to be strictly a religious commitment and property rights associated with that arrangement would have to be explicitly made a contractual and entirely separate agreement between the involved parties, whether part of a civil union type contract or otherwise.

I think we can take it as a given that the GMM will be among the most fervently opposed to this question ever arising.

Marriage as it is commonly practiced in the US is an historical relic from a time when the state and church were functionally combined; the US constitution explicitly forbids state and religious union (I know that's not a direct quote).  The US Supreme Court has a history of straining social camels through the constitutional needles eye, so that isn't a realistic objection.  If all that be true, to be constitutionally consistent shouldn't we either amend the document to grant explicit exception to the "no established religion" prohibition regarding the institution of marriage or write a law that makes formal the distinction between the religious commitment of marriage and the issue(s) of property rights and inheritance and all the rest?

Along with everybody else (to include Mrs. [and Mr. for all of that] Supreme Court Justice), I think it a given the gay folks amongst us will be just as much up in arms about such a ruling as pretty much everybody else will be; they are the stars of the marriage movement at the moment, in this circumstance they aren't any different from their parents and that can't be what equality is all about can it?

I expect this is all built on very shaky constitutional ground and has long since been resolved, but it applies an interesting filter to the questions surrounding marriage nonetheless, I think.