Almost all of the published polls show Obama getting less than 50% of the vote and less than 50% job approval. A majority of the voters either support Romney or are undecided in almost every poll.
But the fact is that the undecided vote always goes against the incumbent. In 1980 (the last time an incumbent Democrat was beaten), for example, the Gallup Poll of October 27th had Carter ahead by 45-39. Their survey on November 2nd showed Reagan catching up and leading by three points. In the actual voting, the Republican won by nine. The undecided vote broke sharply — and unanimously — for the challenger.
An undecided voter has really decided not to back the incumbent. He just won’t focus on the race until later in the game.
So, when the published poll shows Obama ahead by, say, 48-45, he’s really probably losing by 52-48!