"Marriage is between a man and a woman. Period."

This analogy doesn’t hold up. Separate but equal didn’t work because you had to duplicate a complete system for education, etc., that was as good in every way as the existing ones for whites. In the case of equal rights for gays all you need would be a few specific laws. Just for an example. Allow gays to enter into a legal union called X. Than have all the rights of married couples extend to a gay couple. Seems very simple to me. Extremely simple.

For much longer than 200 years it has clearly meant the union of one man and one woman. That’s simply a fact.

I don’t think that correct. Other than anti-miscegenation laws, how has it changed?

Much sooner than if gays insist on changing the meaning of a word and concept that is deeply ingrained in our culture and brains.

The vast majority of changes in marriage of the decades and centuries have to do with how that marriage came about, how a spouse was chosen, and by whom. The one thing that has not changed (a few polygamist sects aside) is that it has always been between a man and a woman. Talking about the issue of marriage with that of how women have been viewed through out the ages conflates two different issues.