Amidst the innumerable excuses we're bound to hear for tonight's Massachusetts election results, credit Keith Olbermann with likely the most loathsome. The Countdown host would explain things away by accusing Brown supporters of . . . racism. [H/t reader Will H.] Olbermann floated his despicable theory to Howard Fineman: "the Republicans and the Tea Partiers will tell you what happens with Scott Brown tonight whether he wins or comes close is a repudiation of Obama policies. And surely one of Obama's policies from the viewpoint of his opponents is it's OK to have this sea-change in American history—to have an...