...at what point does the right wing grumbling about election countermeasures become perceived as insurrection by the left and "allow" them to "attack"? -Uninformed, from the comments
There are a lot of ways to interpret that question.
At one very real level the left started attacking rank-and-file conservatives when the first conservative platform was demonetized. They attack every time they vaporize a blog because it does not meet "their" community standards.
At another level, attack could mean going kinetic or using force-of-law to throw conservatives in prison while giving Leftists a free pass. I expect that to vary by where you live and has already started in the Loony-tunes bastions of Portland and Seattle.
Leftist are probing middle-America, sticking their toe in the water to check the temperature. Louisville, Ky and Kenosha, Wi for example.
They will cherry-pick Patient-Zero in each region, solidify their base and then extend from there.
This could all be stopped dead in its tracks with very little bloodshed if the key enablers (say the District Attorneys who refuse to exercise the laws they swore to uphold) were to start getting Covid.