If protesters are killed, all of those people Trump was looking to peel off are going to come running back to Biden.
Also, Black turnout could skyrocket because of this. And youth turnout in general, this is one of the most engaging issues with the demographic.
That's exactly what I was predicting because of this, and this could very well hurt him in states like Georgia, North Carolina, Florida, and even in the rust belt.
Also I have a feeling that many of the never-Biden democrats are going to reluctantly vote for Biden anyways because of this.