Representative Bachmann speaking about President Obama and the price of gasoline said that Obama is “waving a tar baby around”. In itself, the dictionary meaning of tar baby is not a racist slur, which is what the right wing will say. But as John McWhorter writes:
Part of the human propensity for metaphor is that we make semantic associations, which drift and reassign over time. As such, it’s not the most graceful thing to refer to a black figure as a tar baby, and it was quite gracious for Lamborn to apologize. However, to assume Lamborn knew the word was a slur and was passing a grimy little signal to his base is unwarranted here. It is the kind of reflexive and recreational abuse we revile when it comes from the other direction (i.e. Obama as a “racist”).
Tar baby is one of those intermediate cases: The basic meaning is the folkloric one, while a derived meaning, known only to a segment of American English speakers (and to many among them, only vaguely) is a dismissive reference to black people.
There will be gaffes with expressions like these, upon which, in a sociologically enlightened society, apologies will be necessary. However, to insist upon the moral backwardness of the apologist is logically incoherent in reference to this particular term, and as such, less sociologically enlightened than it may seem.