Predicting the Votes of the Undecided Is Unusually Hard This Year

Debra Deremiah knew exactly whom she would vote for in November: Sen. Hillary Rodham Clinton. With that option gone, the 59-year-old Democrat from Amherst, Ohio, is at a loss.

"I'm undecided, and I am not an undecided type of person," Deremiah said. She said she rarely votes a straight party ballot and is weighing who could "salvage" the economy and who has "the right experience for what we need now in our place in the world."

"I'll vote," she said, "I just don't know which way I'll go."

Nearly half of all movables in the Post poll are independents, as most partisans have sorted out as expected. Overall, independents go 49 percent for Obama, 45 percent for McCain.

Several variables this year make predictions hard. For one, pollsters of all stripes see in their surveys an unprecedented interest in the race, which could lead to record turnouts and alter the normal turnout models. The interest is evident in early-voting states. In the Post poll, nearly two in 10 voters, 17 percent, said they have already cast ballots. And 18 percent said they plan to vote before Tuesday.

The Post poll illustrates a challenge for McCain in making a strong close.

Among those voters who say they are still undecided or open to persuasion, more are currently McCain supporters than Obama backers. So McCain has to fight to hang on to those voters as well as persuade those leaning toward the Democrat. And Obama's supporters seem more enthusiastic. Among all likely voters in the Post-ABC poll, 49 percent say they will "definitely" vote for Obama heading into the final weekend, compared with 40 percent who say the same about McCain.

At this stage in his successful elections in 2000 and 2004, Bush had the solid support of only 44 percent of those polled.

One intriguing question about the undecided voters is whether there is a hidden racial component that would tip them decisively toward McCain. The speculation is that voters might be reluctant to tell pollsters they would vote against Obama because he is an African American, even if they have decided to do so.

But University of Wisconsin political science professor Charles H. Franklin has just completed an analysis of polling data that he says finds no evidence of that. His study of tracking data collected by the Hotline shows that undecided voters -- 6 percent of the total in those surveys -- have similar attitudes toward African Americans as those who have made up their minds. This and other analyses seem to show that whatever role racial prejudice plays in voters' decisions, there is no net effect on Obama's or McCain's level of support.

Staff writer Mary Pat Flaherty contributed to this report.