what is the right tactic for the democrats to defeat this kind of cheating?

well, clinton did the same thing in the 2016 primaries, and we saw sanders pull it off in specific states by sheer volume.

biden will need to get turnout up so far amongst white voters that standard republican cheating tactics fail.

and, it has to be white voters, because those are the votes that get counted, in the end.

he won't. he's fucked.