Undecided votes go to the challenger (KERRY)
 

Charles Cook when asked if it's true that undecided votes usually go to the challenger...

"I cannot remember ever seeing a race where a well-known, well-defined incumbent won a half or more of the undecided vote. Generally it is at least two-thirds to three-quarters going to the challenger, somebody was throwing a figure around of 85 percent, don't know if that is right. But as a general rule, undecided voters overwhelmingly break toward challengers, unless the incumbent is relatively unknown, undefined, appointed or something. That's why it is a mistake for people to focus on the spread between the two candidates, the far more relevant figure is the actual vote percentage of the incumbent in a poll (or better, average of polls). If you assume that Nader/others get about two percent of the vote (down from combined 3.1 percent last time), if President Bush is at 46, 47 or maybe 48 percent of the vote going into election day, he probably loses, 49 percent, on the cusp, 50 percent wins. "

http://www.washingtonpost.com/wp-dyn...7.html?sub=new