Lots of things, such as intentionally placing polling places in inconvenient places (sometimes inside private property where they can't go), having incredibly long lines whilst banning shades and drinking water for those people waiting. Posting cops there who have a proven track record of being extremely racist, since minorities lean Dem, in position to implicitly threaten to beat/arrest/kill any minority who tries. GERRYMANDERING making the votes in Dem areas powerless...
And all of the above leads to a lot of those Dem voters seeing voting as pointless so they don't try. Learned helplessness from abuse.
Intentionally leaving out the fact that the files were sealed during those times so it would've been impossible for dems to do that without breaking the law.
