The Corwin Amendment was proposed before the civil war and passed by both houses of Congress in 1861. It has been left dormant, but could still get ratified.
The amendment was written to try and avoid the Civil war by making banning slavery a state issue, forbidding it to be Federally banned, but i think the text could be applied to prevent the Hate Amendment that bushco want to push through. Since this now has to be ratified by state legislatures, we may be able to get the 3/4's of states needed since (Ohio and Maryland ratified it in 1861 and 1862 so the total number would be 36 more states needed).
Here's the text of what would be the 28th amendment from Wikipedia:
No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State.
Marriage is an institution, no?
See extended entry for more
The obvious parallel of the fact that we could link the moral issues of gay marriage to the moral issues of slavery (even though us voting for states rights on this issue is a bit ironic).
With likely 'activist' Supreme Court Justices to be appointed during these coming 4 years, we on the left have to take over the mantle of being the states' rights party so we don't all become the United States of Freeperville.
Some visibility on this issue and contacting our state legislators could make this a reality.
If someone who is reading this has more experience either in constitutional law/history or public policy making, please weigh in.