Private vs. gay marriage

Various conservatives (of the pomo variety) have been discussing how best to view the inevitable legalization of gay marriage. David Schaengold summarizes:

The argument about gay marriage really is about whether we think homosexual sexual unions as a class should be recognized as [a political] good. This is a question we are not competent to decide as a polity. For one thing, gay couples would be offended that we are talking about the worth of their relationships. For another, as MacIntyre would say, we don’t have the right set of concepts even to start talking about worthy or unworthy sexual relationships. So, given the thrust of public opinion, either we’ll get private marriage, or gay marriage. The latter seems much preferable, even to a reactionary like me. Gay marriage might lead to the destruction of the institution of marriage, but privatizing marriage would be the destruction of the institution.

A related question: how much of my Protestant heritage would I have to give up in order to call marriage sacramental? The whole matter is more complicated historically than I realized. (See Puritan Richard Baxter get messy with the definition of “sacrament.”)