My data-crunching research days are long behind me. That said, I pose a hypothesis a younger somebody ought to test after the election data has all been tabulated and the elected sworn in.
Some data-driven scholar should compare the votes for each of the two major parties in 2016 and 2018 with those of 2020 for the regions where, in the intervening interval, major Antifa and BLM violence, looting, and destruction occurred. My hypothesis, the "troubles" have influenced a significant number of former D voters to vote R in 2020. Comparison groups would be cities with no significant rioting, of which there must be at least a few.
To the extent precinct level data is available, I would anticipate this trend particularly in largely white precincts. You might (or might not) see the opposite effect in minority precincts.
I would also expect the degree of shift to be proportional to the length and intensity of street violence. Portland would likely anchor the high end of that scale.
Another factor to dump into the regression equation is the elapsed weeks between the end of the violence and Election Day. Philadelphia's violence now ongoing should have more impact than, for instance, that of Minneapolis which appears to have ended a month or two ago. Recency is an issue.
