This is what Digby means by dog whistling.
I think we need to have a little discussion of what "racist dogwhistle" means. It is a word or phrase that conjures up certain subliminal images in those who are predisposed to see things in racial terms. It doesn't mean that everyone who hears the word as a criticism sees it in that way --- only those who get "the code." So, when Karl Rove sends out McCain's minions to spread the word "presumptuous" all over the place, the idea is to signal to the racists among us that Obama is "uppity." It doesn't mean that if you think Obama is presumptuous that you are a racist. You might just think, "yeah, he's acting like it's in the bag already." But racists hear that Obama is an uppity black man. See, it works on two levels. That's why it's called a dogwhistle --- only the racists can hear the racism in it.
Digby writes that she gets complaints from liberals about focusing too much on racism. But the thing that strikes me about the idea of racial dogwhistling is that it's overly optimistic. I can see where talking about Obama being presumptuous would be more easily translated into Obama being "uppity" by an overt racist than the average moderate or independent voter. So, dogwhistling there is.
But I think that the main racial effect of these kinds of dogwhistling manuevers would be to raise the anxiety level of moderate and independent whites concerning Obama as a black man. There may be less hard core, overt, racism in the United States than there was in the seventies, but American society is saturated with racial stereotyping of black people and one of those stereotypes is about the "arrogance" and "conceit" of black athletes like Terrell Owens of the Dallas Cowboys vs the ideal of humility to which all athletes are expected to subscribe. The same kinds of stereotypes apply to black musicians, actors, and celebrities as well.
Thus, the efforts of the McCain campaign to portray Obama as "presumptuous" seek to induce racial anxieties about Obama by associating him with "T.O," Chad Johnson of the Cincinnati Bengals, or a variety of hip hop artists that I'm too uncool to be aware of. The idea isn't to stimulate racial hostility but to make white moderates nervous and uncertain enough about Obama that they would be susceptible to other forms of negative advertising.
The other non-dogwhistling aspect of McCain's tactics is that white moderates and independent are subject to cross-currents that hard-core racists ignore. White moderates may become nervous about Obama but they also might find Obama's positions, image, and advertising appealing in ways that counter-act their racial anxieties. In this sense, pushing the "presumptuous" meme either introduces or reinforces racial anxieties as an element that is "in play" for this election. But the working of the "presumptuous" theme on moderate voters would be much more fluid than racial dogwhistling is with hardcore racists.
Pushing Obama's "presumptuousness" does have a racist effect but it's more a matter of raising anxieties in moderate whites than dogwhistling the determined attitudes of marginal racists.