Marcus Smith was working as a waiter at a Democratic fundraiser here the other night when Sen. Barack Obama (D-Ill.) took to the podium. Smith, with dishes in both hands, stopped to listen. "I'd really like to see Obama become the first black president of the United States," he said later. Asked what made Obama black, he replied, "That little taste his father gave him was all it takes."

There it was again, a near reflexive need to categorize and assess by race.

Is Obama black enough for the black vote? Is he too black for the white vote? With a black father from Kenya and a white mother from Kansas, can he expect to take the mixed-race vote? It's as if the "color line" had been encoded into the American DNA.

Obama was doing what he could not to get boxed in.

"It's time to turn the page on division," he said. "What brings us together as Americans is that sense of hope, the audacity to believe that the way the world is today is not the way it has to be."

A "mixed" audience of 1,400 -- the largest ever for the state's annual Jefferson-Jackson Dinner (named for presidents Thomas Jefferson and Andrew Jackson) -- applauded uproariously. But the truth of the matter is, each time the country has turned the page on division, more of it showed up on the next page.

"Will his race be a factor? Absolutely," said Tonza Ruffin, a lawyer from Windsor, N.C., who came to hear Obama. "He will have to go above and beyond to prove that he is capable of doing the job, more so than some of his white counterparts."

When asked the same question, Delthema Allen, a registered nurse also from Windsor, declared: "Absolutely not. Skin color is superficial." When asked what she thought of those who have questioned whether Obama is "black enough," she said, "He's black enough for me."

What happened to just being human? Virginia certainly had a hand in crushing that notion, enacting in 1691, for instance, legislation to ban marriages between free people of African descent and those of European descent. When human nature refused to cooperate, Virginia found a way to keep the social fiction going. In 1924, state officials passed the Virginia Racial Integrity Act, which relied on quackery in the form of the "one-drop rule." Anybody with "one drop of black blood" was black, according to the law, and was prohibited from marrying a "pure white." The color line had become a Gordian knot of racism.

According to a recent survey by Zogby International, a majority of whites, 55 percent, classified Obama as "biracial," and 66 percent of blacks classified him as black. To some, it was ridiculous to question whether Obama was "authentically black" when he was embraced by so many black people. But assigning him to that category only tightens the knot.

Otis Lucas, who manages a group home in Richmond, tried this approach: "It's a very exciting dynamic. He's black and he's white and he's right." But that doesn't cut it, either.

Obama hinted at the crux of the problem when he paid homage to civil rights pioneers. "I stand on the shoulders of hundreds of giants, thousands of people who fought the good fight for so long," he said. And just what were they fighting? A category called white -- and the presumption of racial superiority that came with it. That left blacks with two choices: embrace their skin color with pride or accept it as a mark of racial inferiority. But both options were biological fraud. There is simply no such thing as race.

In 1989, Virginians elected L. Douglas Wilder the nation's "first black" governor since Reconstruction. As the grandson of slaves, the silver-haired statesman epitomized the quantum leaps that black people have made in their trek from slavery to freedom. Wilder demonstrated how far we had come.

Now Obama is showing us how far we have to go.

During a visit to the Virginia Capitol, Obama gazed at the restored White House of the Confederacy just a few blocks away and said, "This reminds us that the country has an enormous capacity for change."

But nearly 400 years after the first Africans arrived in Jamestown and were put to work as slaves, Obama is being shackled by racial categories.

And the color line stretches on.