We've been seeing anecdotal evidence about the increasing difficulty of polling, with call waiting, caller ID and cell phones steadily reducing the pool of voters willing to be surveyed. And this reduction is, in all likelihood, not neutral - it would tend IMO to remove more pubbies from the pool than dems. However, it is interesting that Allard's internal polls were spot-on, so I think the most likely source is deliberate bias on the part of pollsters to try and influence a shift in public opinion. However, IMO in this election the combination of a massive grass-roots effort and Bush's efforts more than countered any such manipulation. Toss in the palpable disgust around the country at the Dem tactics in both NJ and Minnesota, and you have both a powerful push and pull.