Shortly before the Iowa caucuses, a senior political scientist said to me: “When you met me, you first saw a Black man. What do you see when you see Obama?” This colleague was trying to understand how my white-person’s race-meter was responding to the Illinois Senator.

I believe that all Americans respond reflexively to the race of the people they encounter. And I believe that mostly negative stereotypes are triggered when we see someone as African American. The strength of these stereotypes varies, as does our ability to override them; but they almost always lurk beneath (even when the beholder is Black).

Thus we can presume that Senator Obama triggers racist stereotypes. But things are a little more complicated. First of all, I don’t think that it’s only the color of skin that moves Americans’ inner race-meters. We also respond to signifiers of culture and class, such as accent. That’s no less bad than responding to color, but it is a fact about the way we think. While Black Americans speak in every imaginable way, African American culture is marked by a set of accents that have a family resemblance to each other. Most African American accents are rooted in the American South. Senator Obama does not have such an accent, so he is less likely to trigger racist stereotypes.

Further, all kinds of subtle signs mark the Senator as upper-middle-class. Although African Americans belong to all social classes, stereotypes associate Blacks with the working class. Senator Obama thus evades some of the standard triggers of racial identity.

Finally, we don’t meet the Senator the way I met my political science colleague: face-to-face and with a handshake. We meet the Senator on TV. It’s a mediated relationship, the kind we also have with Oprah, Will Smith, Colin Powell, and many other African Americans. I don’t know the relevant psychological literature, but I suspect that mediation reduces the impact of stereotypes that are deeply connected to motives like fear.

So what will it mean if Senator Obama wins the Democratic primary and the general election?

Not that everyone is willing to vote for a Black man, because most people won’t vote at all, and many will vote for other candidates (reasonably enough, given their views on a range of issues). Adam Nossiter found plenty of examples of white voters for whom “mention of Mr. Obama merely provoked discomfort.” Even if he wins the election, most people may fall into that category.

Not that we have achieved racial justice, because race will still be a major determinant of the quality of schools, public safety, health care, and employment opportunities that one receives. And …

Not that the Obama voters have left racism behind, because they might not vote for a Black candidate who has a stereotypically Black accent or a working-class culture.

But it may mean that a governing coalition of Americans have shed racism sufficiently that they can overcome their reflex negative responses to dark skin–and that would be something.