Karl Rove
Advisor to President George W. Bush
Bush's campaign strategists, including Karl Rove, devised a push poll against John McCain. South Carolina voters were asked "Would you be more likely or less likely to vote for John McCain for president if you knew he had fathered an illegitimate black child?". They had no interest in the actual percentages in the poll, the goal was to suggest that he had. This was particularly vicious since McCain was campaining with his adopted Bangladeshi daughter. The sight of the little dark skinned girl made the seed planted earlier grow and John McCain lost South Carolina, effectively ending his run for the presidency.
I have to say, this is extremely disgusting and repugnant. The fact that Rove was still given a job in the Bush White House speaks volumes about the morals of both Rove and the president.