Jill Stein is a Green candidate which means she’s going to pull left leaning support away from Kamala Harris.
If she pulls away enough people in a handful of states, she could throw the election to Donald Trump.
2016 is a primary example:
Pennsylvania:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Pennsylvania
Trump - 2,970,733
Clinton - 2,926,441
Difference: 44,292
Stein? - 49,941
Michigan:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Michigan
Trump - 2,279,543
Clinton - 2,268,839
Difference: 10,704
Stein? - 51,463
Wisconsin:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Wisconsin
Trump - 1,405,284
Clinton - 1,382,536
Difference: 22,748
Stein? - 31,072
If Clinton had won those three states, Trump would not have been President.
Stein is not the only factor, Clinton had other issues. She badmouthed coal miners which guaranteed a loss in PA and utterly failed to campaign in MI and WI which was not helpful.
But the Clinton fans who can’t accept how deeply, deeply flawed Clinton was as a candidate want to blame Stein…
And Putin. There are issues with Stein getting support from both Republicans and Russia, anything to hurt Democratic candidates.
It could, I mean, we don’t know the politics of the covid dead, but look at the numbers:
Pennsylvania:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Pennsylvania
Trump - 2,970,733
Clinton - 2,926,441
Difference: 44,292
Covid deaths: 51,344
Source: https://usafacts.org/visualizations/coronavirus-covid-19-spread-map/state/pennsylvania/
Michigan:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Michigan
Trump - 2,279,543
Clinton - 2,268,839
Difference: 10,704
Covid deaths: 44,728
Source: https://www.michigan.gov/coronavirus/stats
Wisconsin:
https://en.m.wikipedia.org/wiki/2016_United_States_presidential_election_in_Wisconsin
Trump - 1,405,284
Clinton - 1,382,536
Difference: 22,748
Covid deaths: 16,723
Source: https://usafacts.org/visualizations/coronavirus-covid-19-spread-map/state/wisconsin/