Reanalyzing McCain's Threat to "Whip" Obama: Republican Southern Strategy

McCain's threat to "Whip Obama's you-know-what," as I and others have diaried about a few days ago (see below), has been largely dismissed an inconsequential on a number of threads on dkos.
I'm glad that so many have commented, though I'm surprised by the willingness of so many to dismiss McCain's comment so easily.
In particular, it's useful to analyze the comment in the context of recent Republican attempts to portray Obama as alien and the decades-long Republican Southern Strategy to mobilize the white racist vote.