(...snip...)
That's a sensible rebuttal. I would accept this if it was just states deciding whether the legal age of marriage was 15 or 16 or 18, but not if it's states deciding that some consenting adults do not ever possess the right to marry each other, even though both are full qualified to marry someone of opposite sex. If two individuals are full qualified to marry someone of opposite sex, then the state should have no right to prevent them from marrying each other absent some compelling interest that can only be satisfied through that discrimination. That might (or might not) be demonstrable for incest, but with gays openly living together (and in many states marrying) without bringing on Armageddon it obviously isn't true for homosexual marriage. Otherwise we are not truly free creatures. The only true societal impact I'm seeing is by preventing gays from marrying but allowing them to openly live together, raise children together, even adopt children to be raised together, we are forcibly denying the benefits of marriage to some portion of our population. Children don't choose to have gay parents, and they should not be prevented from having the greater security of married parents simply because some of us find it icky or un-Christian, even if that "some of us" happens to be a majority.