This question might be better asked here rather than the election thread: has there ever been a notable case of election fraud in the history of the US? If so, any in the past fifty years?
Election fraud, yes. Voter fraud -- a subset of election fraud -- yes, but almost unheard of. Election fraud includes such things as deceptive voter suppression tactics, improper mass handling of ballots, improper mass registrations, and a whole lot of stuff that can be committed before the election occurs. Some have had the potential to affect results. Most do not.
Voter fraud in the past fifty years has almost never occurred. That's stuff like casting someone else's absentee ballot, trying to vote more than once, voting when you're not registered or eligible, voting in a district other than where you live. The major university study that passed quickly under my eyes in the past few days (murky, so I don't recall citations or accurate details) identified on the order of 1,500 cases of voter fraud or attempted voter fraud in 2 billion votes cast. For any given vote in the 2020 Presidential election, that's a prior probably of
p < 7.5 × 10
-7 that the vote was cast fraudulently.
In my home state of Utah we've voted almost exclusively by mail for the past 10 years. We have a very robust, effective, and efficient protocol for handling ballots accountably, including bipartisan observation and control.
However, this is the first year our primary elections were done by mail. The Republican primary is a closed election, so the clerks had to introduce provisions to send ballots to, and make eligible, only registered Republican voters. The Democrats previously had a primary caucus, which they abandoned this year because of the pandemic in favor of an open primary (any eligible voter can vote). And for the first time, 17-year-olds could register to vote if they would turn 18 on or before Election Day. But due to a programming error, primary election ballots were sent prematurely to those 17-year-olds. But because they're barcoded, it was a trivial matter to instruct the tally computer to reject those if they were somehow submitted. There is a bipartisan audit trail for everything like that.
The other thing that has happened in my state is that parents have filled out mail-in ballots for their sons and daughters serving out of town as Mormon missionaries. State law allows them to vote as absentees in that case, and the ballots were completed at the instructions of the actual voters. The parents just acted as proxies. But this is still very illegal, and they got caught. The signature-matching test failed. Ballots cannot be forwarded, but it's the voter's responsibility to make sure it's mailed to the address where they are physically located.
In short, the claims that voter fraud is a serious problem, or has been at any time in the recent past, have no basis in historical fact.
