Whites in VA do not equal whites in NC.
I don't know how saying, "if the relative black vote in Virginia was 3/4 of Kerry's base, it's realistic that it could be 3/4 or less in North Carolina," implies that they are the same or comments on to their similarities/differences in any way.
I understand, but that wasn't the tenor of the comment. I suspect 40% is the ceiling, frankly, and I still believe it will be more in the 33%-35% range.
Still, I believe that NC should fundamentally be a 10%-15% win for Obama, in the same way that Indiana should be a 5%-10% win for Clinton.