Today was Josh Marshall's turn among the race-baiting high-minded liberals who pretend not to remember that a man fired 29 shots at the White House in an assassination attempt against Bill Clinton for which he now serves 40 years. He praises a column by Maureen Dowd, who said that she "imagined" Joe Wilson saying "You lie boy," rather than "you lie." There is no story Dowd cannot twist and turn in order to fit her desired narrative.
Some people "cannot or will not accept that a black man is the President of the United States," Josh says, ignoring that those same people would not accept Hillary Clinton either.
Why didn't conservatives go around attacking black Supreme Court nominee Clarence Thomas during the confirmation hearings? Because he was an ultraconsevative, just like them. 
What is the magnitude of Republican hatred against Michael Steele? nonexistent. Republicans only attack Steele when he says something not conservative enough.Michael Steele is black.
If Barack Obama were a Republican, conservatives would love him. He would still be black.
Glenn Greenwald has a list of  very nasty attacks on Bubba (false accusastions of rape, calls for a special prosecutor to investigate the possibility that Bill Cl;inton killed Vince Foster, the booing of the President because he was perceived to be illegitimate for failing to gather 50% of the vote against Ross Perot).
Etcetera.
Playing the race card works in a primary, against a white Democrat such as Hillary Clinton who everyone hates, because of the way the media is structured. In a primary, left, center and right-wing outlets agree to pretend that the statement "Obama's Iraq policy is a fairy tale" is racist. Drudge fakes outrage. David Brooks feigns praise for Hillary's rival, and Rush Limbaugh waits until Obama's victory is imminent before he "supports" Hillary in order to undermine the future Presidential candidate.
But post-election times are different. Playing the race card during the Gates incident backfired. Polls showed sympathy for Crowley.
Because Republicans control the media.
Today, what could have been a post-speech bump became nothing due to what I believe is the incessant harassment of southern whites, who must be pissed off that everything from "you lie" to a joker poster created by a Dennis Kucinich supporter is racist. We have heard more about Joe Wilson than about Obama's effective speech.
Keep playing the race card at your own risk.