The “margin of fraud” seems like one of those quaint old sayings from the past, since we are now in an era where Democrats are willing to turn in vote counts that are 200% of the number of registered voters in a district.
It used to be 1% (and I mean a full percentage point, not with rounding) which can be many tens of thousands of votes, depending on the race. Now it probably 2-3% with mail in shenanigans.