CNN polling guru Harry Enten finds Joe Biden's lead not only holds up through national polling, but it holds up through various state polls as well.
In the competitive states (where most of the state polling has been conducted), there has been an average swing of 6 points toward Biden compared to Clinton's 2016 result. The same is true in the non-competitive states.
At least from this state level data, it does not seem that either candidate is running up the score disproportionately in areas that were already friendly to him.
Biden has posted leads of greater than 5 points in places like Michigan and Pennsylvania. He is ahead in more than enough states to capture 270 electoral votes, if the election were held today.
We can test our data, too, to see what would happen if the polls are underestimating Trump like they did in 2016.
What I found was Biden would still be ahead, even with a 2016 sized mishap.
The polls underestimated Trump by 1 point (RealClearPolitics) or 2 points (FiveThirtyEight) in the aggregate of the states we currently have polling from. Applying that 2016 bias to our current data, Biden would have a 6- to 7-point lead nationally.
Concentrating on just the competitive states, the polls undersold Trump by 2 points (RealClearPolitics) or 3 points (FiveThirtyEight). If the polls in the competitive states were off by as much as they were at the end in 2016, Biden would still be ahead in states like Florida, Michigan and Pennsylvania.
Of course, it may not be wise to expect a 2016-sized polling era in 2020. The polls in these states that had major statewide contests in 2018 were pretty much unbiased. No matter what set of states (all or just competitive) and which aggregate, the polls were not more favorable to Republicans than the final result.
In a state like Wisconsin, the final 2018 Marquette poll nailed the final Senate margin and underestimated the Democratic candidate for governor's margin by 1 point.
The bottom line is Biden's ahead right now nationally and in the competitive states. The good news for Trump is he has about six months to change the course of the campaign, which is more than enough time to do so.
In a regular America, Biden would be well on his way towards a decisive win. In Trump's America in 2020, with COVID-19 and the most blatantly criminal autocrat in modern US history rigging the outcome, absolutely nothing can be taken for granted, including even having an election in the first place.