States do NOT maintain voter rolls up to date.
Approximately 19 million households move each year. If just over half have 1 registered voter, say 10 million registered voters. If 5% do not update their registration, that is 500k fraudulent entries on the rolls.
Annual deaths are 2.8 million/year. say half or registered voters, that ia 1.4 million. CDC notes by 8 weeks only 75% of states are updated. So how deaths are not updated with county election offices thru the year. Let's say 5%, that is 70k
That is 570k for one year on 2 cases with conservative numbers.
How many of those vote by mail might get filled out fraudulently?
Safe guards and up dated rolls need implemented prior to considering a mail in standard.