“The question is whether or not the federal government under a federalism system has the authority to regulate marriage...”
Isn't the question whether the federal government under a federalist system has the authority to regulate entitlements?
The whole discussion is confused by the fact there are two issues in play.
The first concerns love and commitment to a partner. That is not in issue for me. Of course society should not prevent homosexual people from tying the knot. Even so, I don't assign a "right" to it. It's just something that is none of anyone else's business. Same as with heteromarriage. The law should not be written to discriminate.
The second concerns special entitlements for married couples. To me, the existing benefit is discriminatory against unmarried people as a class (using the current definition) rather than against homosexuals. In my view, a more egalitarian solution admits that the privileges are justifiable in favour of and should be assigned to parents rather than married couples.
But I see no reason why the lesbian partner of a deceased spouse in a nulliparous marriage should not pay a tax on the estate, whereas the heterosexual partner of a deceased person in an informal relationship which produced children must do so. For entitlement purposes, the existence of children is more significant to me than the existence of a piece of paper.
As usual, it seems that I derive a different position than the set-piece positions in the press. This gets frustrating.