If the Whitey tape exists and is released - IMO, it will do nothing but embolden the black community to vote in larger numbers. I suppose it will embolden white people as well, but the white supporters of Obama already mostly turn a blind eye to the reverse racism of the Obama campaign - so, I think it will not matter to them and/or they will be pacified by whatever demurrer he and she proffer.
In the end, I think the D's are fools for chosing, albeit mostly through caucases and in states that are electorally irrelevant, Obama. But, the D party historically is not the swiftest
In the end, he may win though because people buy into what he says even though the facts rarely support what he says.