Fortunately the world is not limited to what you recall. Lets just call documented fact "conspiracy theory" and pretend like it doesn't exist. I guess voter fraud is only important when it doesn't serve your interests.
You have extremely flexible standards of what passes for a "documented fact". The NC 9th district case was a serious one, they had to re-run the election. A republican still won BTW so there is an argument to be made that even this case of fraud didn't really change the outcome.
How many such cases can you show let's say in the last 20 years? Proven in the court of law, with the potential to change the outcome of an election.