We aren’t going to see a federal constitutional amendment. Not only does it not even poll with a majority (which is at least a bear MINIMUM for the probable success of a constitutional amendment), but many of the big names in even the conservative side of things oppose it.
What we will see are states doing what they can to ban.
But I do think having gay marriages on some books, even illegally, does get us something. Suddenly we have the family values crowd trying to break up people’s marriages. That’s a pretty powerful irony that the gay rights crowd can and should play to the hilt.