With the election of President Barack Obama, rumors abounded of a "post-racial" era. These were overstated. Now, with the president finding his partisan agenda rejected by public opinion, Democrats have begun to shout "RACISM!" in Obama's defense. This is not helping Obama.
Presidents are parodied, insulted, mocked, hated, and often shot at. This has never been blamed on race before. By running for the presidency, Obama (and his co-competitors in 2008) were volunteering to become a receptacle for vitriol. We chose Obama; we didn't have to.
When Democrats - in Congress or the media - refer to criticism of Obama as "racist", they hurt the cause of blacks in politics.
Those who play the race card are rarely colorblind; they are typically actively interested in the promotion of racial equality, or simply in the promotion of their own race. Either way, they think about race a lot. Most white Americans (and thus most voters) don't think about race a lot. If they do think about race, it's as a distraction from real business, from people doing their jobs. They - we - want a president who does his job, who makes no excuses, and who treats us voters as worthy of his respect.
When critics of the president are dismissed as racist, they will conclude that their accusers have no rejoinder of substance, and aren't ready for the rough business of Washington. This came into play during Hillary's campaign: her defenders played the "woman" card, and voters recoiled. Who wants to be tarred as chauvinist for criticizing the president? Voters instead chose Obama, who (then and now) has done an admirable job at taking punches without whining.
Democrats outside the White House, however, continue to diminish the president by defending him on racial grounds.