But even before the official polls the early (year or so before primaries, or in older cases, conventions) frontrunner, especially in the Dem Party rarely ever got the nomination.
Adlai was the frontrunner for '56 but came out of relative nowhere in '52.
FDR won the nomination at a chaotic '32 convention.
This stuff makes me feel a bit better about Hilary's current status...but American voters have shown some incredible lapses over the years (64, 72, 02, 04). As much as I would like to believe that American voters wont be duped by "Hussein Osama' stuff or by staggering early poll leads, I wont be surprised when/if we are.