The pool of undecided voters on Election Day could be as large as one in 10, but John McCain can hardly rely on them to overtake Barack Obama. According to past election results, undecided voters are unlikely to break decisively for either candidate and dramatically alter Tuesday’s race.
In the past eight presidential contests, voters who made up their minds during the last week of the campaign never went for either ticket by large margins of 3-2 or 2-1, which potentially could tip the scales.
“There is likely no hidden life raft in the undecided vote for John McCain,” said Andy Kohut, director of the Pew Research Center.
Pew recently conducted an internal analysis of its polls and concluded that undecided voters were likely to split about equally between McCain and Obama on Election Day, meaning the group is more evenly split between the two candidates than the electorate overall, Kohut said. In the coming days, Pew, like the Gallup poll, will finalize its best estimate for how undecided voters will cast their ballots.
Since 1976, when exit polls first asked voters when they made up their minds, about 10 percent to 25 percent of voters consistently told pollsters that they didn’t decide until the final week of the campaign.
Pew’s recent studies found that 8 percent of the 2008 electorate remained undecided, similar to its findings among registered voters in the last week of the 2004 election. Other recent surveys from Ipsos/McClatchy Poll and the IBD/TIPP Tracking Poll generally match Pew’s results.
Data shows that undecided voters are significantly more likely to be women, 63 percent to 37 percent. They are more likely to be working class, while about half have a high school education or less. And by double-digit margins, undecided voters are less engaged in the presidential race than those who have already made up their minds, according to Pew.
Those who decided in the final week broke only slightly for Ronald Reagan in his 1980 blowout of Jimmy Carter; Reagan won the election in a landslide, 59 to 41 percent, after he famously outperformed the incumbent in the campaign’s sole debate one week before the vote.
The Reagan-Carter race and the 2000 matchup between George W. Bush and AL Gore are the only presidential contests since 1952 in which the leader in the Gallup poll taken about a week before the election lost the popular vote.
That offers only some solace to Obama, who is campaigning hard against complacency as he races to the finish. In part, his half-hour, prime-time television advertisement tonight, with an estimated price tag between $3 million and $5 million, is aimed at securing the vote of his supporters as well as wooing fence-sitters.
But it’s McCain, who trails in the polls by a larger margin than Kerry did four years ago, who needs the undecided voters as he heads into the last sprint of the campaign. Absent a dramatic turn in the race, however, recent history suggests McCain will have to focus on soft-Obama supporters to mount any last-minute surge — the tactic successfully adopted by Bush in his campaign against Kerry.
In 2004, as Pew forecast in its final poll, Kerry won the voters who decided “sometime last week” by 52 percent to 47 percent. But the margin was too slim to boost the Democrat to victory, since only 9 percent of voters were late deciders.
In 2000, fully 17 percent of voters decided in the final week of the campaign, but they split closely between the candidates, tilting to Gore 48 percent to 45 percent. But that slight margin, when translated into votes, was about equal to the 500,000-vote margin of victory Gore won in the overall popular vote.
Despite evidence to the contrary, the ability of undecided voters to alter the outcome on Election Day often is overemphasized. In 1988 and 1996, as in 2004, the losing candidate won late deciding voters. And in 1976 and 1992, late deciders roughly split between the two major party nominees.
That could be because late-deciding voters tend to return to their partisan leanings on Election Day, as noted by James Campbell, a political scientist at the State University of New York at Buffalo who has studied undecided voters.
But today, an unusually large share of undecided voters –- as many as half -- are “pure independents,” according to Pew. Campbell said that should be “encouraging” to McCain, because they likely remain highly persuadable.
Still, Campbell said his own analysis of the undecided vote left him skeptical of an eleventh hour wave. Indeed, Campbell said, “the best odds are that undecided voters will split very evenly” on Election Day.