If a Republican pollster can't have Trump any closer, he's doomed. However, I think this might actually be the margin Joe Biden wins Pennsylvania in November. He'd be winning by more if the election was held today, but (I assume) the numbers will somewhat tighten towards the end of the campaign.
Why do people assume this? If anything Biden’s lead could get bigger.
Some assumptions-
1) Polarization has effectively made double-digit PV victories impossible
2) When things get bad, they tend not to get any worse
3) Trump and his base will commit any number of crimes to win
4) Between the conventions and the debates, the media tends to get a lot more Republican friendly. They usually just start with a bunch of things like Hillary and Huma's friendship or Obama's old co-workers or something and then ends with dog whistle allegations corruption. You could call it "swiftboating".
5) We're not that lucky.
