The first fair election in the US in the last 70 years will happen when all voting is in person, on one or two days, with voters dipping one of their fingers in purple ink to prevent voting more than once.
dipping one finger in purple ink won’t work. the truly dedicated leftist radical will just cut off the purple finger then vote again. it would take 3 or 4 voting cycles to identify them.
In person double voting is a very minor issue. Mail in and absentee voting with bad voter registration on the otherhand is a very major issue. Voter registration needs to be in person, with ID, and be redone every 4 years because voters move, die, get incarcerated or sent to funny farms, develop severe dementia, brain damage etc. Political parties (Democrats) will exploit every hole in the registration process to cast ineligible votes.