Sorry - in politics, the worst possible thing one American can do to another is to imply that they're not really American. I'm a liberal from Indiana - that may or may not mean anything to you - but somebody identifying me as a not-quite-American based on something I say that maybe sounds too posh really raises my hackles, even as I realize, full well, that it's a really stupid reaction.
Even then, I didn't really notice it until I'd read three things I say that an American wouldn't. Dammit. It's like the time that chick in Germany tried to tell me I don't speak English, just American. I may not know everything, but by God and St. George I am the utter master of my dialect and precisely how and when it differs from whatever we Anglophones deem "standard".