But I assumed he could at least strike the right tone on matters of race and color. Yes, I know he was the black guy elected to not say anything about color, but I refused to believe Obama would stick to that deal, at least not all the time. But then came the humiliation of watching Obama backtrack on his (correct) opinion about the racial profiling of scholar Henry Louis Gates Jr.; more recently, there was the panicky, preemptive firing of Department of Agriculture employee Shirley Sherrod for allegedly making anti-white comments.

And late in July, Obama described black folks as a "mongrel people" on the morning talk show "The View." Responding to Barbara Walters' question about why he didn't call himself a biracial president, he explained that blacks are mixed and always have been. That's strictly true. But "mongrel" was a terrible choice of words, the kind of animalistic imagery segregationist whites once used to justify their treatment of blacks (especially men), who they feared would poison a "superior" gene pool. "Mongrelization" was in fact a word used passionately by the Democratic Party in the 1850s, by the Ku Klux Klan and by early eugenicists to describe that awful outcome.

But I can forgive Obama's use of the word. What was less forgivable was that the president missed — or consciously passed up — a racial teaching moment that he is uniquely suited for. He started off in a promising direction: He told Walters that early in his life, he decided that if he was going to be called an African American, he "wasn't going to run away from that." Not exactly a ringing endorsement of African Americans, but all right. But in a rhetorical triangulation of the sort that has become all too familiar, he went on to say colors were "labels" that were far less important than how people treated each other, a sentiment that got predictable applause.

What that moment revealed is the constant pressure on Obama to gloss over questions of color, starting with his own, and subvert the entire history of black people whose experience he shares. The celebrity interview glitter of "The View" masked a clearly white supremacist attitude that demands blackness be defined to its liking and adjusted to its comfort level.

When Walters pressed Obama on why he doesn't call himself biracial — after helpfully reminding him that he had a white mother — what she was really asking is why he doesn't put white folks like her more at ease by downplaying or modifying his blackness, which, post-racialism notwithstanding, continues to be so nettlesome. Obama essentially obliged her. He implied that his black identity was somehow a choice. But that's nonsense. In America, there has never been any choice about being black. One white parent makes you lighter, or maybe gives you different hair texture or a social advantage. But the historical reality is that you are not equal to whites; you are, like Obama, only the exceptional Negro.

Such a reality is the choice of white people, by the way. It was whites who made and brutally enforced the racial rules, including the one-drop rule that declared that any black heritage (one-sixteenth, to be exact) made you too black to be anything but. Racist? Of course, but it was meant to be.

But the fanatical separation of races codified in Jim Crow laws and customs also helped create a diverse community of blacks who understood that blackness in America was never monochromatic, and that all blacks — half, three-quarters, whatever — were in the battle for justice together because they had to be. Now, to recast "mongrel" blacks, which is to say almost all black Americans, as biracial or "black lite" is not a stab at equality; it's just stupidity.

The problem is that the real experts — ordinary black Americans — are rarely in on these debates. They aren't asked to be. Or they're invited to participate only to co-sign the "raceless" point of view that's already been sanctioned. That is the corner Obama was in on "The View." He may be president, but what the show made clear is that he's black first.

Compounding the surreal quality of the moment was black co-hosts Whoopi Goldberg and Sherri Shepherd sitting silently, nodding at Obama's conclusion that color is less important than people respecting each other. Again, true. But color and mutual respect are closely connected in this country; there is only a shade of difference between them. Obama not only knows this, he has seen it up close. Next time, he needs to tell us that in no uncertain terms.

Erin Aubry Kaplan is a contributing editor to Opinion.