There's a lot more wishful pontificating there than there is actual data. I couldn't read the whole story as it's subscriber-only, but in the section you've cited Marshall hangs his hat on the answer to one question. Then he extrapolates from there - quite liberally - to guess what pitches will and will not work in Wisconsin.
Here's a counter, offered with more data:
https://www.marketwatch.com/story/tr...st-11598901254
I can tell you because I interact with Rust Belt Democrats and Republicans all the time, moderates on both sides do not like the riots, or the "defund the police" stuff. Marshall can present a cherry picked poll answer and then fictionalize about how the riots are impacting voters in a manner that fits what he wants that impact to be, but he's talking out of his ass.
Biden's leading, but the riots are hurting him. Marshall is correct that Trump has not capitalized on the riots yet as he might, but I have three observations in response to that which are so obvious it makes me wonder how Marshall gets paid to write what he wrote there:
1. It's all about timing. If Trump crushes the riots right now, he's too close to the election. The value of his doing so is potentially forgotten or diminished by November 3.
2. Trump's bet on young progressives is that in the states that count, They Don't Vote. BUT, if he has a Kent State on his hands because he fucks up the response to the riots, young progressives might actually vote. Why take that risk now, when they could register in time to vote? Take that risk closer to election day, when they won't be able to do so as easily.
3. The riots are helping Trump. He's out there, telecasting to fence-sitting voters that if re-elected, These Riots Will End. You don't squash the riots when the riots are helping you until the moment that squashing them can provide a bigger boost than not squashing them. You ride that wave of fear. And you say this on TV all the time: "When re-elected, when I have nothing to fear from a lying media which will portray law and order in a bad light, we are going to end these riots. For good."
Is Trump that smart? Maybe. Maybe not.