Nate Silver warned Dems that, yes, they “should be nervous” about Joe Biden’s chances in Pennsylvania, and hence, the ENTIRE election:

The money quote from the article’s summary: “Yes, Biden and Democrats should be nervous that he has only about a 5-point lead in Pennsylvania, the most likely tipping point state.”

The lead is even narrower in the RCP average, FWIW:

In 2016, Silver says polls were off by 4.4 points so it wouldn’t take much more of an error for Trump to win the state:

Oh, and the latest poll from the group that predicted Pennsylvania correct in 2016 has Trump ahead (although Silver has called out Trafalgar’s methods this year):

And this map explains why President Trump was in Maine and is going to Nebraska as both those states split their electoral votes. The scenario below looks to be Biden 270, Trump 268 with Nebraska all for Trump and Maine all for Biden: