OK, let's have it...

As Bill O'Reilly says in this clip, if the same-sex marriage opponents want to win in November (assuming the proposed amendment to the Constitution makes it to the ballot), they are going to have to come up with a logical reason why same-sex marriage is bad for California. All his guest can come up with is, "because that's the way it's always been."

I don't think they can do it. The fundies have three basic arguments:

1) "It's immoral."
This is easily dispensed with. Whose idea of "moral" do we choose? Many religions think gambling is immoral, but the state runs a lottery and there are dozens of casinos, card rooms and race tracks in the state. Standing on morality means relying on religious belief as the basis of your argument, and given this is a secular issue, that won't stand with a majority of voters.

2) "Marriage has traditionally been one man, one woman."
This isn't any more valid than the first, but this may be the hardest nut to crack. The definition of marriage, contrary to what the right keeps repeating, has changed a great deal over the past two millennia. It was originally a matter of property, designed to link powerful families. In some cultures, during some point in their history (including modern-day Islam), "marriage" could mean one man, many women. It used to be that marriage truly meant "until death do you part." Modern divorce laws have changed that. More than once. For many years "marriage" did not include couples composed of people of different races.

The challenge is, no matter how much logical reasoning you deliver to some people, they will simply be unable to change their mind in terms of what they will tolerate. There will be a large segment of the population, primarily older, who will dig in their heels and say, "I like it the way things are."

3) "Children do better with a mother and father in the home and traditional marriage supports a stable environment for raising children."
First off, there is no fertility means test for marriage. Infertile couples, or those beyond childbearing age are not denied marriage licenses. Even fertile couples who choose not to have children are allowed to marry.

Second, whether you like it or not, non-traditional family arrangements can create children. Single women go to sperm banks, lesbian couples do the same or find male friends to donate the needed cells, and women get pregnant out of wedlock and choose not to marry the father, for whatever reasons. Denying committed same-sex couples the right to marry will not change that one whit.

There is no evidence that children in families headed by a same-sex couple do any worse, but even if it happens to be true, giving the children of same-sex couples a more stable environment (which marriage will certainly do) is obviously a good thing. You can't keep gay people from having children, but we can at least provide the option of a more stable relationship setting for them to grow up in.

The battle continues.