has more than a little irony to it. He is the beneficiary of a euphemism. The underclass has changed from black to colored to negro, back to black, of color, and now in imitation of other immigrant groups, African-American. The problems with African-American is that the connection with Africa is vanishingly thin, modern Africa is nothing much to be proud of, and that Africa is a geographic area not a country nor a people. (Asian American is equally useless - it includes Israelis, Tamils, and Russians from Irkutsk.)
But African-American and only African-American is permissible (aside from the penumbra of the n-word, used among themselves but forbidden to others). Now they are hoist on their own petard. Obama is an outsider to the underclass. Since he is literally an African-American there is no denying him the description. So the result is that many African-Americans see him as an interloper, an opportunist, because he is not one of them. Similarly, many whites like him for the same reason - because he is not one of them. African-Americans lose their main weapon, the race card, and liberals get to feel good about themselves.
The whole situation is reminiscent of the controversy over who actually wrote the Shakespeare plays. Mark Twain opined that they were either written by William Shakespeare or by someone else of the same name.