Anyone interested in US racial and ethnic politics needs to go read this article in today's New York Times Magazine, now.
As everyone who has studied race relations knows, white in the United States is defined negatively, and some whites, eager to play the "cool" card, embrace hip-hop, Orientalism, "ethnic" food and fashion, or, in the extreme, distant racialized ancestors in their family trees.
And you know what? IT SUCKS. It really does. And the imbeciles who do it and go all-out just don't deserve to live. So what if your great great great grandmother was an Indian? YOU'VE got your middle class white privilege, while the REAL Indians, the ones for whom ethnicity isn't a matter of coolness but just a fact of life, live in terrible, grinding poverty and crime. See, because *real* ethnic groups don't have a choice; they're labeled, and that label isn't cool--it just hurts.
You wear your "ethnic" clothing, and everyone thinks you look chic. I wear the same clothing, and people will think I'm an outsider and treat me as such. You wouldn't be doing this if it meant honestly and truly becoming a second-class citizen. Get over yourself, already, white man.