Race issues add air of uncertainty to polls

The year was 1984, and the state was Iowa. A white man who had just voted walked out of his precinct caucus and saw the Rev. Jesse Jackson standing outside.

"I did all I could," the man told Jackson ruefully, "but I just couldn't bring myself to pull the lever and vote for you."

L. Douglas Wilder laughs as he relates the story Jackson once told him, the sting eased by time and Wilder's vantage point as the nation's first elected black governor.

Now it's a quarter of a century later, and the man everyone's talking about is Barack Obama, the Illinois senator holding a slim lead in many polls. But can the polls be trusted? A central question about race and politics hasn't changed since 1984: Do white people lie - to pollsters or even to themselves - about their willingness to vote for black candidates?