Let's face it - the thing that gives Barack Obama's presidential candidacy its incredible buzz is the fact that he's black. (OK, actually half-black, half-white, but such Americans identify themselves as one or the other, and Obama has identified himself as black and that's the way he's taken, so for all intents and purposes he's black.)I'm not saying he's gotten to where it is only because he's black. There have been other black candidates for US president - Shirley Chisholm, Jesse Jackson and Alan Keyes, at least. But what set Obama apart from them, from the start of his campaign, was that he truly had a chance to get to the White House - because of his unusual charisma, intelligence and knack for the "vision thing"; his essentially mainstream politics; and his self-definition as an all-American, not black American, leader.So I think it's fair to say Obama would have been a presidential contender even if he were white - just on the strength of his personal qualities. But what gives his candidacy such electricity, what makes him so "hot," what makes his campaign into an honest-to-God movement and what makes people, especially the young and the liberal, want to be a part of it, is the fact that he's a black contender. The possibility that America, whose history has been so blighted by white racism, will elect a black president - the sensation of it, the nearly messianic prospect of such a thing actually happening, brings tremendous added value to Obama's candidacy.And he obviously knows it. His message is mainly himself: a black man (OK, half black African, half white American) who really could become president of the United States. That, not his politics, is at the heart of Obama-mania. As great a speaker as he is, I don't think his speeches would have the galvanic power they have if he were white.He can depict a vision of a multi-racial, multi-cultural, equal-opportunity America like no other political leader partly because of his superior rhetoric and oratory, but also because he alone not only depicts the vision, he embodies it.In the political movement he leads, he is irreplaceable. Without Obama, there's no movement. Without Obama to give it flesh, his message seems banal.By being the first black American with a shot at the White House, Obama offers a truly messianic vision - of an America that, by virtue of having elected a black president, will have finally washed its long, terrible racial history clean. A fresh, new America, one where race doesn't matter any more. A black president, Obama's hardcore supporters seem to believe, would revolutionize race relations in America, or at least improve them greatly.I DISAGREE. The vision of a racially healed America after Obama becomes president is just pie-in-the-sky.To an extent, though, I'm also excited by the idea of a black president. (I support McCain because of the Iraq issue, but on most other criteria, race being a very minor one, I prefer Obama.) Having someone other than a white man in the White House can't hurt. It would probably even help a little. It would make some people feel better about America. I'm sure I'd be one of them.But America remains a rather segregated country, especially when it comes to where people live and who their friends are. I don't think that's going to change if Obama wins on November 4.More importantly, I do not see blacks living in what's called the "culture of poverty" - with unstable families, violence, ignorance, teenage pregnancy, drugs and alcohol, crime and various other social pathologies - breaking out of it because they've got a new, better-than-ever role model.Blacks in America's ghettos don't lack for role models. Maybe the most respected, beloved public figure in the country is a black woman, Oprah Winfrey. Her title probably used to be held by Bill Cosby when he was in the limelight; now he's a revered American elder. For the last eight years, the US Secretary of State has been black - first Colin Powell, who might well have gotten elected president if he'd have run, and now Condoleezza Rice, a leading future contender for the presidency if she seeks it.Has the example of Cosby, or Oprah, or Powell, or Rice gotten one black American out of the ghetto? I doubt it, and I doubt that a President Obama could pull it off, either.AND AS for America's white racists, those who would never vote for any black presidential candidate, they haven't been swayed by Cosby, Oprah, Powell, Rice or anybody else, so why should they be swayed by a President Obama? A black president might even make them hate blacks more, make them even more convinced the blacks are "taking over."I am old enough to remember an America where there were no blacks in any positions of leadership, when a black man in a business suit drew stares because it was such an unusual sight, when a walk-on black character in a TV sitcom was a shock. This was American life before about 1967 or 1968. I remember when the only black elected official of note was Congressman Adam Clayton Powell of Harlem, when no American city or town had a black mayor, and I remember the hope for an end to ghettos and racism with the election of the first black mayors, congressmen, senators and governors.It never came.The civil rights movement and the black power movement brought legal equality to blacks, forced the government to start spending money in black communities on schools, hospitals and the like, and enabled the emergence of a large, solid black middle class that is now in its third generation and growing steadily.But after 40 years of black "mainstreaming" and the rise of countless blacks to positions of power, America's urban ghettos are as big and as bad as they ever were, if not bigger and worse. The same goes for America's prisons, which are about 50% black.Meanwhile, at the unofficial level, in people's neighborhoods, in people's social circles, America, though much less so than it was 40 years ago, is still basically a segregated country.The election of a black president would not be a breakthrough for America - it would be a logical continuation of America's openness to letting blacks rise as high as their ambitions and abilities can take them. I don't think a President Obama would make America's black middle class any larger, because they'll do fine without any more role models. He wouldn't make the black ghettos any smaller or less deadly because role models don't seem to have done any good there, and he wouldn't shrink the preserves of white racism because they're allergic to people like him.The glow over the election of a black president would last a few days, then it would be over, and afterward Obama would succeed or fail in office for the same reasons every other president has. If he gets to the White House, he might change America like he promises - but if he does, it won't be because he's black.