Civil Matremony

I basically agree with Mark Kleiman here on the question of gay marriage and Obama's stance on the same. Mark's short summary of Obama's position is

since gay marriage is bitterly controversial among various religious groups, and the state doesn’t need to take a position with respect to that controversy, it shouldn’t.

Which works well enough as a summary, although I would say that there are a few more wrinkles to the issue. And, as the commenters noted (go check the link) there are important issues of language, which are not easy to resolve.
Basically, there are, potentially, two aspects to "marriage". One is the legal status, defined by the state, the other is the religious sacrament of Holy Matrimony. The state should have virtually nothing to say about the later. If a group of poeple choose to form a social network in which they will perform ceremonies for one another only under certain conditions, that should be their business, the state should not intervene. The legal status, however, the status defined by the state, should be inclusive, people should be able to enjoy that status without discrimination. I believe Obama's position does no more than recognize that this is the case.
Now that does still leave one problem, which is somewhat thorny. Having read the comments to Mark's piece I see reasons for both sides. Namely, which of these two conditions gets the term "marriage". I'm inclined to leave "marriage" with the religious ceremony and have civil union work for the legal status. But, as I said, read the comments to see the opposite view.
I think ultimately this conflict is resolvable and either choice will work.