Justin Levitt has been tracking allegations of voter fraud for years. "To be clear," he says, "I’m not just talking about prosecutions. I track any specific, credible allegation that someone may have pretended to be someone else at the polls, in any way that an ID law could fix." So far, he's found 31 cases representing around 200 individuals. If every one of them turns out be a genuine case of fraud, that's a fraud rate of:
Of course, Levitt might be off by an order of magnitude. Or maybe even two or three orders of magnitude. That would put the fraud rate at 0.02 percent. On the other hand, these are just allegations. If past performance holds true, nearly all of them will turn out to be clerical mistakes, which means we're back to 0.00002 percent. This compares to many thousands of voters who have been turned away from the polls for lack of ID in just the past few years.
Also worth noting: every single one of these cases involves just one or a few people. There's not a single credible case in the past 15 years of any kind of organized voter impersonation scam of the kind that might actually affect the outcome of an election. There's just no there there.