You cannot steal an election with negative ads or SUPER-PACS. Stealing an election means f**k with the votes themselves.
The poll demonstrates that half of the GOP is so sure Obama couldn't win without voter fraud that they'd blame anything. The fact that the number is largely unchanged from 2008 makes this more obvious.
You could probably go as far as "a black man must do voter fraud to win the election" in their eyes since it's true for both elections.