Remember that in SC, polls taken the day before the election had gay marriage winning big. Once voters had their opportunity to express their true feelings in secret, it was massive the other way.
You mean North Carolina? Actually I think the last few polls released before the vote had the Marriage Amendment winning comfortably by double-digits. Even so, it is true that the Amendment’s ultimate 21 point victory was higher than any poll had it winning by.
The only poll I can remember showing majority opposition to the Amendment was some poll done by, I think, Elon. It was so wrong, and such an outlier, that its hard to believe that it wasn’t fixed.