I think any real movement in the polls is variability in enthusiasm among voters who have largely made up their minds. The question is whether or not they'll be able to vote. Slate.com has released a guide on the best way to vote in each state: https://slate.com/news-and-politics/202 … guide.html
In 2016, the main problem with Democrats was that voters who disliked Trump and Clinton equally and went with the lesser known politician. In 2020, those voters who dislike Trump and Biden equally are going with the one who is inclined to save them from COVID-19 rather than pretending that it'll magically disappear with no federal response.
As for those who support a president who's collapsed their economy, destroyed their jobs, attacked their health care and intends to let them die without lifting a finger to help them -- they're in a cult of personality where their fealty and independent thinking have been subsumed to following their chosen leader rather than see that they voted and will vote again for someone who has betrayed them. It insulates them from seeing the horror of their situation and so they march in streets unmasked, call Dr. Fauci a fraud for telling them hard truths and claim a gunman who shot unarmed man was acting in self defense when he fired on those trying to disarm him. (By this logic, a murderer can only be charged for his first kill and the rest of his body count doesn't count at all.)
Then there who see Trump clearly and will vote for him because they are fortunate to benefit economically from Trump. Such supporters have seized upon the COVID crisis to extract more wealth from the poor.
The rest see Trump for what he is: someone who will inflict his views on people with coersion, rhetoric, attacks drawing on improvised fantasy -- and they admire that because they too go through the world shouting down anyone who disagrees with them, seeking to defeat them with volume and grievance rather than facts and respect for subjectivity.
Informant called you and me liars for viewing the Marvel Cinematic Universe as a success for releasing 13 hit movies in eight years and viewing the DC Extended Universe as a failure. (The DCEU is airing its finale on a streaming network.) He admired that Trump didn't need facts, information, teamwork, curiosity or any need to update his views based on information, even unwelcome information. Informant likes a bully. A lot of Trump supporters do and might feel diminished by a pandemic only to be fired up by a convention that pretends the pandemic doesn't exist and encourages them to do the same.
I don't want to believe that's all Americans. I confess that I think poorly of Americans because I see most of them as Trump and Informant. But in recent weeks, I listen to Grandpop and I don't see you that way at all. I see this:
Joe Biden wrote:
This is the United States of America. Any time we've ever set our minds to something, we've never failed as long as we've done it together.
Everybody thinks that we've led the world because we're the most powerful nation in the world. And that's true. We are. But we've not led by the example of our power. It's been the power of our example.
I really believe that the vast majority of the American people are truly decent. I think they're angry right now. I think they're fed up. I think they're looking for some authenticity and honesty. I think it's going to be hard, but I think they're going to be with us.
Biden has not done anything to piss me off in three whole weeks and he keeps doing everything I ask him to do in my fan mail including requesting the release of Tara Reade's documents, reminding the world that he has a stutter, adopting the Green New Deal in all but name and handling crazy people with calm.
(Biden emerged from a limo in Pittsburgh carrying three boxes of pizza for some firefighters at their station. A heckler standing atop a truck started screaming at Biden about how Biden was going to eliminate fracking and decimate the oil and gas industry. I feared another crazed eruption of incoherence from Grandpa Joe, but Biden merely looked at the man sternly and called out, "Don't jump!" Thank God. Let's see if Gramps can make it one more week without blowing his stack and then it'll have been a month.)