Ross Douthat aruges that even if they are code words, they haven't been effective:
Think about it this way: Maybe the "Joe the Plumber" line is a super-coded attempt to play the race-and-welfare card. Hell, maybe all of the race cards McCain has supposedly played - linking Obama to Paris Hilton; cutting an ad with too many white women in it; cutting an ad with too many black men in it; disrespecting community organizing; calling Obama "disrespectful"; bringing up Obama's ties to a (white) domestic terrorist; describing Obama as "that one"; and so on - have been completely cynical attempts to tap into the white electorate's latent or not-so-latent racist sentiments. If this is your take on the election, though, you should acknowledge that if these were all attempts to play the race card, they've been pathetic attempts - weak, bank-shotting, detached from the major issues of the campaign, and so sub-sub-subliminal (Obama is a celebrity ... Paris Hilton is a celebrity ... Paris Hilton is a slut ... Paris Hilton is a slutty white woman ... sex ... Obama is a black man ... black men are randy ... Obama wants to have sex with Paris Hilton ... Obama wants to rape white womanhood!) as to be more or less pointless.