A few of you might know that I'm actually a political scientist. That's what I studied.
I follow politics as a hobby.
I - like many of you - am fascinated by the US election. Just a couple quick (non-partisan) thoughts in this thread.

Polls are only as good as the "popular opinion". If someone is ashamed of who they vote for, they lie. Even to pollsters they don't know. It happened in 2016. And, for other examples it happened even in Alberta when the Social Democrat party (The NDP) won in 2015.

Generally when this happens, the polling data leans away from the "socially unaccepted" figure by almost exactly the margin of error of the polls.
Trump's win in 2016 didn't prove the polls were wrong. They just proved that societal opinion plays a HUGE part in polling.

The more controversial the candidate, the more the polls fall to the edges of the poll's margin of error.
And it doesn't need to be a "bad/evil candidate". Just a controversial one. Pre-2015 The Cons led Alberta since 1971. 44 YEARS!
Voting NDP was a vote against the norm.

So what does that mean for 2020 in the US?
I think that depends on how much you think people are ashamed of who they're voting for (on either side). Are people going to hide that they're voting for Trump more? Or Biden?

Personally, I think people have become extremely confident in their praise for both candidates. I think the polls are still going to lean in the favour of Biden. But, for the most part, I'm expecting them to be fairly true.

A look at how the NDP vs. Cons polled in Alberta in 2019 after the surprise of 2015 showed that:
1) Pollsters corrected their mistakes from 2015.
2) Since they were in power, it was seen as "acceptable" to admit you voted NDP.
2019 polls in Alberta were basically spot on.

I'd say, look at the polling average on a site like FiveThirtyEight of each state, and give Trump an extra point.

As a result, my prediction is that Biden will win with with 279 electoral colleges. https://www.270towin.com/maps/zeAbb 

BUT, I should add that this theory could also lead to a Biden landslide. If Trump is socially accepted as "popular" in southern states like AZ, Texas, Georgia, NC, and FL polls could be wrong the other way leading to a landslide loss for trump: https://www.270towin.com/maps/J0P3y 

Personally, I don't think there's a way Trump carries enough states to win. But, a friendly reminder that it IS within the margin of error of polls for Trump to win. So, don't give me the "the polls lied!" line.
They are just data.