It is starting. David Neiwert has the details
So far, we have been regaled with the oft-repeated "Hussein" note, the Fox smear of Obama's Muslim background, followed by Limbaugh's astonishing riff on "Barack the Magic Negro". That these reflect a barely concealed racial animus mixed with general white xenophobia should be obvious, and notably, these are all occurring on a national scale, within ostensibly mainstream media sources.
For right-wing audiences, cues like this signal just how far they can take things themselves. So on the public level, the result of this kind of talk is a regular outpouring of old-fashioned racist bile, permission having been granted by leading right-wing voices.
One could say this is the end product of conservative mainstreaming of these bizarre perspectives on the world.