Xan mentioned the new Quinnipiac poll that has Warren narrowly ahead of Biden nationally. This is interesting from the internals on enthusiasm numbers for black and non-college educated voters, core Biden constituencies:
Quinnipiac poll on whether you would be “excited” if one of the 2020 Dems became the nominee:
Black voters: Biden 70%, Warren 68%, Sanders 63%
White Democrats w/o college degree: Warren 69%, Biden 54%, Sanders 52%
— Dave Weigel (@daveweigel) September 25, 2019