The main problem with polls is how the media love them -- it requires no research or other work to write a story about who is ahead in a poll. Do they become a self-fulfilling prophecy? Maybe yes, to some extent -- the idea that a voter says "well, I want to vote for Kerry but everyone else seems to be voting for Bush so maybe I should too" or "why bother voting for Kerry when Bush is going to win anyway". But in Canada, during our election in June, the polls showed Martin and Harper neck and neck all the way - then Martin won 135 seats and Harper 95. Things turned in just the last few days -- only the tracking polls picked up the change.