I grew up in a right wing province of Austria and saw that sort of wrong polling throughout my youth — which is why I wasn't surprised the slightest about things going as they did.

It boils down to: a fraction of the electorate will vote for $bigotcandidate but would never ever admit it to anyone outside the voting booth, because they know it is wrong. They will tell people they will vote for $notbigotcandidate, but vote for him nonetheless.

This fraction is not insignificant and you cannot easily represent it in polls without guessing the effect. In my home province it eas consistently around 10 to 15% over a decade.

I don’t see how that explains the Collins/Gideon race, but I’m not a Mainer. Anyone here from Maine can chime in why a Mainer would lie about voting for Gideon?

My same question. OK you can be claim to be a "good Republican" and vote Biden but (R) down ballot. Why were Senate and House races also wrong? Why did Lindsey Graham win by so much when the polls didn't give him that lead? In South Carolina, it's ok to say you'll vote for Graham.

Bigots turned out. And lean Collins.

The campaigns do not rely on the publicly available poll data for the reasons you pointed out - they need accurate polling in order to make serious decisions about resources. They pay polling companies to get accurate polls and they keep this data private.

The publicly available polls are done for free by polling companies or by news organizations. Unfortunately some of these companies apparently have an agenda to push. So they skew their sample away from what the likely voters are to get the result they want for propaganda purposes.

I think that the rise of Nate Silver has ironically made this situation worse. He advocates taking an average of polls to get a true view of the situation. So if you are skewing you poll to get a certain outcome and you know the poll will be averaged, you need to warp your results even further.

Ok, disclaimer time - I don't have any inside knowledge or real evidence of any of the above. It does seem to fit however. I can't explain why it seems all the distorting is to make the Dems lead seem bigger than it is - that is, why aren't there pollers on the other side of the aisle doing the same thing?

So you'll have to decide for yourself if there is any merit to the above theory.

Biden's campaign said their polling showed the race as closer than the public polling. It also doesn't do good to have too positive polling if it suppresses turnout. And it doesn't do the pollster's reputations any good to be consistently wrong.

I've heard several hypotheses, but I don't have anyway to test them. They all seem to have merit.

The issue with your assertion is that it doesn't account for all the times the polls are right. See most mid-term elections.

I think we have to seriously consider that Trump just breaks things that otherwise would be working within reason.