This is nonsense all the way to drivel.
No demographic group can vote as a near monolith, election after election, for decades without buying into the quarry that spawned it.
There may be a few sensible splinters that broke free, but we have in the black community a liberal group that worships at the alter of liberalism.
Every once in a while the black community accidentally stumbles in another direction (see defense of marriage in California), but it recovers nicely by the next month so it doesn't need to justify the tenets of the Democrats.
To say anything else is a Republican delusion.
If only 5% - 10% defect this election, it will make a huge difference in the outcome. Add the same amount for Hispanics, and the same amount for those that voted for Obamagabe last time but have seen the light, and it is a landslide win for Romney.
Republican delusin is right. In 1976, some Republicans were even predicting that blacks would cast a majority of their votes for Ford. Carter knew not to get disturbed over that prospect.