The winner is determined when the votes are counted. Polls give Obama a large (9%) lead at this time, but they are often wrong.
What does "demille" have to do with the subject of your question?
You should look at the opinions of people who are going to lose large sums of money if they get it wrong, see here:
(Broken Link Removed)
Demille - A ? is a list of candidates on which citizens vote