Should Obama win the White House, he will initially be hailed by the Left as the "first black" to hold the oval office.
But, if that's true, then Obama's ascension severely undermines many of the most sacred tenants of leftist orthodoxy--e.g., that the United States is a racist nation, that the system is rigged to advance the interests of wealthy WASPs over others, and that programs like affirmative action are necessary to remedy the inherent unfairness of the system. In other words, Obama's election will be subversive to traditional Democrat constituencies in a manner that few on the Left have yet contemplated. And, I don't expect these constituencies to easily forfeit their long-held notions about America, notions which now form a part of their very identity and by which they have gained power and influence, just because we have a "black" president.
So, not long after Obama is inaugurated (if he is inaugurated), I expect to be told by those who determine such things that Obama is not the first black president after all. Among other things, we'll be reminded that his mother was white, and that he went to a whitey school. In short, his black bona fides will be questioned by those on the Left who stand to lose far more from Obama's ascension than any of us libertarians or conservatives will.