If your primary political news source is TV, radio or print media you're aware that the "Rev. Wright Controversy" is a huge issue. One that weighs heavily on voters minds around the country. You might also know that the issue is completely overblown, that in reality people are far more concerned with bigger issues then whether or not Obama agrees with everything his pastor said.
The media manufactured nature of the controversy has been well documented here so I will not cover it again.
There is doubtlessly a real resonance amongst some voters about the issue. For them the issue is not about Wright directly, rather, he is a proxy for the racism that cannot directly be spoken of nowadays.
Rev. Wright is being symbolically manipulated to being Obama's shadow persona. Wright, like Obama, is an intelligent, articulate, charismatic black man. The difference between them is that Wright is publicly emotional and angry. Wright is the living nightmare of the white racist; he is a trouble-maker, a black man who doesn't know his place. Obama, in contrast,
is not a threatening figure to most whites. He is quite similar to Tiger
Woods, a sucessful, mixed race prodigy: a culturally approved black male.
Obama walks a tight rope in his race presentation. He must appear strong and presidential, but not in a way that threatens the institution of white privilege. Even more so than Hillary or McCain, his actions must be closely self-scrutinized so as to not inflame racist tendencies.
Voters concerned with the Rev. Wright issue are those vulnerable to the fear that beneath Obama's cool exterior lurks an angry black man, like Wright. This is at the essence of the Manchurian candidate meme that Fox is pushing.
Let's call a spade a spade; the Rev. Wright controversy is about tagging Obama with an "angry black man" shadow that can be manipulated against him during the election and even after he has won. The Rev. Wright based attacks on Obama are all about race: they are racist.
Rev. Wright is the Dean scream of 2008.
Update: In regards to the title. First of all the phrase is not racist in origin. Its meaning has always been "to speak plainly," well before spade became a derogatory term. The "spades" I'm referring to in the title are the racists themselves, i.e. the Wright based attacks are about tagging Obama with a racist meme.