If 40% were undecided (leaving 40% / 20%), that still means that at least three quarters of all the undecideds had to vote against Ahmadinejad for him to lose.

If 40% were undecided (leaving 40% / 20%), that still means that at least three quarters of all the undecideds had to vote against Ahmadinejad for him to lose. I've not seen any polls with 60% undecideds.