If you've seen the movie The Legend of Bagger Vance (which is a terrible movie even if you like golf, so I don't know why you would have wasted two house on it like I have) you are familiar with the character of "the magical negro." As described in Wikepedia:
The Defiant Ones (and maybe a little in Lillies of the Field, too) or the character John Coffey in The Green Mile.
The magical negro is typically "in some way outwardly or inwardly disabled, either by discrimination, disability or social constraint," often a janitor or prisoner. He has no past; he simply appears one day to help the white protagonist. He is the black stereotype, "prone to criminality and laziness." To counterbalance this, he has some sort of magical power, "rather vaguely defined but not the sort of thing one typically encounters." He is patient and wise, often dispensing various words of wisdom, and is "closer to the earth."
The magical negro serves as a plot device to help the protagonist get out of trouble, typically through helping the white character recognize his own faults and overcome them. Although he has magical powers, his "magic is ostensibly directed toward helping and enlightening a white male character." It is this feature of the magical negro that some people find most troubling. Although the character seems to be showing African-Americans in a positive light, he is still ultimately subordinate to European-Americans. He is also regarded as an exception, allowing white America to "like individual black people but not black culture."
Why is the "magical Negro" such a common literary device? About a year ago, when this term was getting a lot of use, this piece in the LA Times summed it up nicely:
He's there to assuage white "guilt" (i.e., the minimal discomfort they feel) over the role of slavery and racial segregation in American history, while replacing stereotypes of a dangerous, highly sexualized black man with a benign figure for whom interracial sexual congress holds no interest.And here's where it gets complicated. The "danger" that is posed by the stereotypical black man is heightened if that black man is angry. Note that none of your "magical Negro" characters ever show anger, unless for comedic effect. White America is petrified of the angry black man. Perhaps because that same white guilt whispers in our ear that he has a pretty good reason to be mad?
Obama has been a real life personification of the "magical negro" story-telling technique - seemingly wise, appearing out of nowhere to help us solve our problems, and never angry. The Rev. Wright, on the other hand, has anger to spare. And whether he is entitled to that anger or not, that makes him a scary black man, and we sure don't like the scary black man. Obama's magic is tarnished by association. We wonder if he is just hiding his anger, and in reality he too is a scary black man.
Newt Gingrich has suggested in an interview with ABC that Wright may be trying to damage Obama. Whether that's his intention or not, that is what he's doing.