Campaigning, he addresses the race issue without hesitation, once even mimicking gangbangers - he criticized their work ethic: "Why I gotta do it? Why you didn't ask Pookie to do it?" he said.
He quotes Martin Luther King and occasionally slips into the cadence of a black preacher, but recent polls show is the choice of more black Democrats, and it's clear that Obama's racial identity gives pause to some. He is not the descendant of African slaves, but is the son of a white mother and a Kenyan father, so he alone gets questions about just who he is.
"My black activist friends from here to Boston say that you are not black, you are multiracial, and I want to know how you self-identify?" he was asked at a recent event.
Obama replies: "I self-identify as African American - that's how I'm treated and that's how I'm viewed. I'm proud of it."
"The issue of whether he is black enough is not the primary issue," said Michael Fauntroy, a professor of public policy at George Mason University. "The issue is whether he has enough experience."
Besides, Obama may have other strengths. "He is seen as more palatable and more acceptable to larger numbers of white voters," Fauntroy said.
Of course, there are whites who will never vote for Obama because he is black.
"I don't want to sound prejudiced or anything, but for one, I am not going to vote for a colored man to be our president," said one South Carolina voter.
When asked if this country would vote for a black man for the highest office in the land, Sen. Obama deflects the question, suggesting merely raising it is a disservice to the American electorate.
But the American electorate has never had anyone quite like Barack Obama to consider.
Copyright 2007 CBS. All rights reserved.