I mean, you can't prove a negative. We cannot prove there is no voter fraud happening anywhere. We can only show that there is no evidence for it, and further,

I mean, you can't prove a negative. We cannot prove there is no voter fraud happening anywhere. We can only show that there is no evidence for it, and further, that it is reasonable to conclude that lack of evidence suggests a trend (that is, we can show that we're also actually looking for evidence).