That's "Intermittent Gunderson Syndrome." John Cole describes it thusly:
You might want to check your children to see if they are suffering from an outbreak of Intermittent Gunderson Syndrome (IGS). Symptoms include a fake accent that appears to come and go, use of folksy mannerisms when in front of a national audience, inadvertent winking, and the loss of the ability to pronounce the letter “g” at the end of words.
He is talking, of course, about Marge Gunderson in Fargo and Sarah Palin.