Ding ding ding! I worked 30 elections in Texas. (Travis county--almost as left as San Fransisco.) Saw statistical evidence of fraud between my first & second as an election election judge. Had an attempt to vote by a non-citizen who stated, "That never stopped me in Houston."
Oh yeah, then there was that infamous precinct (101) which had 0 registered voters, but almost always managed to record a vote.
I also know when & how some of the changes in the procedure that were used over the years changed what could be done in terms of corrupting the process.
Then there's my daughter, who, in Washington state doing block walking to registered voters, came across non-citizens who were on the rolls weekly. And let's not forget the governor's race when a Seattle precinct had 101% voter turnout, and the judge refused to do anything about it.
Or, if you like something that's easy to confirm, in 2020 (yes, THAT 2020), we had a candidate for the legislature _publicly_ thank the post office workers for inserting her flyers into the mail. Yes--that's one of the few ways that election fraud violates federal law (interfering with the mail).
Not to mention, light most people with an awareness of IT security, I was screaming from the rooftops about the insanity of electronic voting as soon as I heard about the idea. I didn't change my position recently.
In truth, in most jurisdictions, there are a lot of safeguards in place to prevent election fraud. And I have found myself explaining to people that various dubious-sounding events are in fact not suggestive of fraud. But if you've worked enough elections, and you are intelligent and pay attention, you're going to come to understand that it's happening.