New Marist/PBS & NBC/WSJ polls bring us to a critical mass of October live-interview national polls, and to me Biden's gains appear to be pretty even across the board (except for Black voters, where there wasn't much room to grow).

To be clear, "final 2016 polls" are via @Nate_Cohn/ @UpshotNYT's estimates and this chart is my running average of 2020 national live-interview poll crosstabs, including NYT/Siena, CNN, ABC/WaPo, NBC/WSJ, Fox, Marist/PBS, Quinnipiac, Monmouth, Suffolk and Grinnell/Selzer.

One fascinating takeaway is that Biden's 12% lead over Trump is the same size as in June/July, but:

1) far fewer undecideds today (54%-42% vs. 52%-40%)
2) Biden's average lead has expanded by 4% since June/July among seniors & Hispanics

Also: to the extent there are still undecided voters - and there aren't very many of them compared to 2016! - they skew young and Hispanic/Latino.