Can only white people be successful?

recently, i was talking with a person who is an avid supporter of hillary clinton for president. i brought up the idea of condi running against her, for an unprecedented woman v. woman election. my friend quickly dismissed the idea of condi running for president because she was an "oreo." which she meant "white on the inside and black on the outside." as crass as this sounds, this is not the first time i've heard someone refer to condi rice, or colin powell for that matter, as a member of the white establishment. i've even seen tshirts that have a picture of condi and read "i work for whitey."

this leads me to ask, what about condelezza rice and colin powell make them "white" on the inside? is it because they are successful? educated? intelligent? wealthy? part of the mainstream? because their political views are conservative? or maybe because they don't spice up their sentences with phrases such as "what's up my boo?"

when thought of in this manner, my friend's "oreo" comment might be one of the racist statements i've ever heard. ... although she might outwardly claim to be open-minded and accepting (by virtue of being left-leaning), she harbors the stereotype that only white people can be part of the educated, ruling class.