WASHINGTON

Since the nation’s birth, Americans have discussed race and avoided it, organized neighborhoods and political movements around it, and used it to divide and hurt people even as relations have improved dramatically since the days of slavery, Reconstruction and legal segregation.

Now, in what could be a historic year for a Black presidential candidate, a new Associated Press-Yahoo News poll, conducted with Stanford University, shows just how wide a gap remains between Whites and Blacks.

It shows that a substantial portion of White Americans still harbor negative feelings toward Blacks. It shows that Blacks and Whites disagree tremendously on how much racial prejudice exists, whose fault it is and how much influence Blacks have in politics.

One result is that Barack Obama’s path to the presidency is steeper than it would be if he were White.

Until now, social scientists have not closely examined racial sentiments on a nationwide scale at a moment when race is central to choosing the next president. The poll, which featured a large sample of Americans (more than 2,200) and sophisticated survey techniques rarely used in media surveys, reflected the complexity, change and occasional contradictions of race relations.

More Whites apply positive attributes to Blacks than negative ones, and Blacks are even more generous in their descriptions of Whites. Racial prejudice is lower among college-educated Whites living outside the South. And many Whites who think most Blacks are somewhat lazy, violent or boastful are willing or even eager to vote for Obama over Republican John McCain, who is White.

The poll, however, shows that Blacks and Whites see racial discrimination in starkly different terms. When asked “how much discrimination against Blacks” exists, 10 percent of Whites said “a lot” and 45 percent said “some.”

Among Blacks, 57 percent said “a lot” and all but a fraction of the rest said “some.”