I like Herman Cain on his own terms (I hope that Sarah Palin declares, but I think that Cain’s heart is in the right place and his business experience invaluable). I think it is highly unlikely, though not impossible, to see black Americans en masse turn from the socialist Obama to the patriot Cain just because he is black.
Don’t forget that Cain is resolutely opposed to ethnic politics and would not campaign hard to give the black community its “fair share”; instead, he wants to give everyone a fair shot, and that message won’t be enough to mobilize the Obama-oriented black community, in my opinion.
This has been the GOP position going back at least 20 years: when everybody prospers, black people prosper too.
My bet is a large number of blacks are coming to realize the Won is a monumental screw-up and would welcome a chance at immediate redemption of their skin color. And of course, there is the question of their own economic prospects, along with those of the rest of the nation.