The fact that the Democratic nominee, Joe Biden, is uninspiring compared to his primary rival Bernie Sanders, and was a key sponsor of Republican policies such as the crime bill, NAFTA, Welfare reform, and the Iraq War, which will cause low turnout from Non-whites, Youth, and Union Workers.
I just don't see the low turnout playing out as has been evidenced from 100 million voting prior to election day. I would have maybe agreed with this back in Jan/Feb, but I think that "I am going to stay home as opposed to voting for a candidate I don't like" attitude is much less strong this time around. I will say that young, male, people of color may fall into the non-voter category (and will be somewhat surprisingly supporting Trump).
While I agree that Biden isn't an
inspiring candidate, he's not a disliked candidate (like Hillary was).
Also... the "shy Trump voter" thing plays both ways in strong Trump areas (e.g., The Villages in Florida).
Polling would need to have a larger, different error (or multiple errors) than in 2016 (maybe under weighting GOP turnout and over counting GOP defections).
